Obstetrics and Gynecology – final examination M = the Merck veterinary manual R & O = veterinary reproduction & obstetrics (Noakes…) CAR = compendium of animal reproduction (published by Intervet) P = Physiology of small and large animals (Ruckebusch, Phaneuf and Dunlop) T = current therapy in Theriogenology (David A. Morrow) 1. Female genital anatomy of the cow and investigation of the sexual apparatus of the cow 2. Female genital anatomy of the mare and investigation of the sexual apparatus of the mare 3. Female genital anatomy of the ewe and investigation of the sexual apparatus of the ewe 4. Female genital anatomy of the sow and investigation of the sexual apparatus of the sow ♀ genital organs include: Ovaries (gonads) * 2 Uterine tube (fallopian tubes) * 2 Uterus =Horns (connect by bifurcation) * 2 Body * 1 Neck (cervix) * 1 Vagina Vulva Mammary gland Mare Ovaries = bean-shaped (7-8 cm long and 3-4 cm thick) Located in the sub-lumbar region 4/5 lumbar vertebra (position is in-constant) The ovary free border leads a narrow deposition = ovulatory fossa Connections = attached to the sub-lumbar region by the anterior part of the broad lig. of the uterus (mesovarium) = attached to the uterine horns by the ligament of the ovary (lig. ovarii proprium) – a band of muscle enclosed between the layers of the broad lig
Transcript
Obstetrics and Gynecology – final examinationM = the Merck veterinary manualR & O = veterinary reproduction & obstetrics (Noakes…)CAR = compendium of animal reproduction (published by Intervet)P = Physiology of small and large animals (Ruckebusch, Phaneuf and Dunlop)T = current therapy in Theriogenology (David A. Morrow)
1. Female genital anatomy of the cow and investigation of the sexual apparatus of the cow2. Female genital anatomy of the mare and investigation of the sexual apparatus of the mare3. Female genital anatomy of the ewe and investigation of the sexual apparatus of the ewe4. Female genital anatomy of the sow and investigation of the sexual apparatus of the sow♀ genital organs include: Ovaries (gonads) * 2
MareOvaries = bean-shaped (7-8 cm long and 3-4 cm thick)
Located in the sub-lumbar region 4/5 lumbar vertebra (position is in-constant)The ovary free border leads a narrow deposition = ovulatory fossaConnections = attached to the sub-lumbar region by the anterior part of the broad lig. of
the uterus (mesovarium)= attached to the uterine horns by the ligament of the ovary (lig. ovarii
proprium) – a band of muscle enclosed between the layers of the broad ligUterine tube = each connected to the broad lig. (mesosalpinx) reaches the ovary and forms a
pouch together with the broad lig. (bursa)Uterus = situated mainly in the abdominal cavity, but extends also into the pelvic cavity
= the body and horns are attached to the abdominal and pelvic walls by the broad lig.= the broad lig. extend on either side – from the sub-lumbar region and the lateral pelvic walls
to the dorsal border horn and lateral margin of the body of the uterus the lateral layer of each gives off the round lig. of the uterus (lig. teres uteri)
Vagina = passes in the pelvic cavity and related dorsally to the rectum and ventrally to the bladderVulva = related dorsally to the rectum, ventrally to the pelvic floor, laterally to the sacro-sciatic lig.,
semimembranous muscle and internal pubic arteryMammary gland = 2 in number in pre-pubic region
EweGenerally resemble the genital organs of the cowOvaries = almond shape (1.5 cm long)Mammary gland = 2 in number
CowOvaries = oval and pointed at the uterine end (3.5-4 cm long 2.5 cm wide and 1.5 cm thick)
= have-no ovulatory fossa = situated near the middle of the lateral walls of the pelvic inlet
Uterine tube = enveloped by the broad lig.Uterus = almost entirely in the abdominal cavity
= the horns are 35-40 cm long= the cervix is 10 cm long and cm thick (very dense)= the body contains 100 cotyledons – irregularly scattered or arranged in rows (in non-
gravid uterus they measure 1.5 cm , but during pregnancy they greatly enlarge)= the broad lig. are-not attached to the sub-lumbar region like in mare, but to the upper part of
the flank – about a hand-breadth below the level of the tuber coxae= the round lig. are well developed and can be traced distinctly (near inguinal ring)
Mammary gland = 4 in number
SowOvaries = rounded
= concealed in the bursa ovarii (due to the large extent of the mesosalpinx)= position is variable
Uterus = horns are extremely long (up to 1.2-1.5 m long) and freely movable (large broad lig.) in non-pregnant animals they are arranged in numerous coils
= the cervix is very long (10 cm)Mammary gland = 10-12 in number
BitchOvaries = elongated-oval and flattened (2 cm long)
= situated a short distance behind (or in contact with) the posterior of the corresponding kidney (3/4 lumbar vertebra or half way between the last rib and the ileum)
= the right ovary lie between the duodenum and abdominal wall and the left one is laterally to the spleen each is concealed in the bursa ovarii
Uterus = body is very short (2-3 cm), but the horns are very long (12-15 cm)= the horns are nearly straight and form a V-shape towards each kidney
Mammary gland = 10 in number from the posterior part of the pectoral region to the inguinal region (pectoral, abdominal and inguinal glands)
5. Diameters of the female bony pelvis and differences between the pelvis of various species of animals (from anatomy)
6. Sexual maturation – puberty, age at first breading
Sexual maturation – puberty (R&O - 2-5, CAR - 259)
Mare 12 – 24 monthsCow 7 – 18 -“-Ewe 6 – 15 -“-Goat 4 – 8 -“-Sow 6 – 8 -“-Bitch 6 – 20 -“- early in small breed and later in bigQueen 7 – 12 -“-
Influenced by age, maturity (body weight), individual genotype (breed) and environmental influence.Environmental influence on puberty:
Nutrition = good feeding good growth rate early puberty (but unless the animal is severely malnourished, the onset of cyclic activity will eventually occur).
Season of the year = in seasonal beading species (as ewe, mare…) puberty depends on the time of year at which the animal was born.
Proximity of ♂ = exposure to mature ♂ of the species (mainly in Su and sheep) may advance the onset of puberty (“boar or ram effect”) => probably mediated by pheromones and other sensory elements (sight, sound, touch and smell) that influence hypothalamic GnRH secretion.
Climate = animal in tropic areas reach puberty at an earlier age than those in temperate climate (not true in cattle)
Disease = any disease that influences the growth rate (directly or by reducing feeding and utilization of nutrients) delay onset of puberty
No domestic animal has physiological changes comparable with the menopause of women.When the ♀ reaches puberty genital organs increase in size, ovaries become active (produce ♀
gametes and synthesis of hormones), graafian follicles become mature (up to puberty they develop only to the stage where they have theca interna and then they undergo atresia).
The main hormone responsible for onset of ovarian activity (and hence puberty) is Luteinizing Hormone (LH).
The reason for the first “silent” estrous of the pubertal animal is believed to be because the CNS requires to be primed with progesterone before it will respond (behavioral signs of heat)
Age at first breadingMare Fillies are often seen in estrus during their 2nd spring and summer
(when they are yearlings), but under natural conditions it is un-usual for them to foal until they are over 3 years old
Cow 14 month Should attained at least 65-75% of their mature weightBeef Bo breeding starts 3 weeks before the main herd (dairy Bo
breed all year so it doesn’t apply to them) so they start to calve before the heard extra time needed for re-breed and they get closer attention
Ewe 7-8 m. (41-45 kg BW) Vary greatly and influenced by breed, nutrition and season of birth (photoperiod)
Goat 7 month or 30 kg BW 7 (5-10) month if born early in the year (Jan/Feb) late born may not cycle in the first season (puberty at 15-18 month)
Influenced by body weight (nutrition), age, type of birth, presence of buck, climate and season of birth
Must reach at least 60-75% of adult weight before breeding (allow mother development and increase kids viability)
Sow 5-8 month 5-8 month depend on genotype (including degree of in-breeding), body weight, nutritional status, season and management (boar effect is the most important, cross breeding, changes in housing and forming new groups)
If estrus does not occur until 8 month of age or if the gilt was serviced for 3 consecutive heats and do-not conceive must be culled (if gonadotropins were used to bring these gilts into estrus the progeny should not be kept for breeding)
At the first estrus the number of ovulations is low, but it increases so if mating is delayed until the 3rd heat a larger litter will result
Bitch 6-7 month 6-7 (4-22) month small breads have first heat in 6-10 month large breads have first heat in 18-20 month
Queen 5-12 month Non-pedigree cat = 7 month or 2.3-2.5 kg= influenced by body weight (most important),
season of birthPedigree cat = oriental cat (as Siamese, Burmese) 5 month
= long hair cat over 1 year
7. The estrus cycle in the mare (R&O – 10; CAR - 61)Seasonal normally (spring to autumn normally un-estrus in winter) some may cycle regularly
throughout the year (enhanced if the mare are housed, given supplementary food and additional light is provided)
Winter estrus is followed by a period of transition (estrus may be irregular or very long) to regular cyclic activity (early heats may not be accompanied by palpable follicles, an-ovulatory and manifestation of heat is a-typical)
Foals are normally born in spring and summer (food supply and environmental conditions are optimal)
Pregnancy lasts 11 month (310-365 days) so the estrus season overlaps the parturition season first estrus after parturition (foal heat) occurs 5-10 days post-partum (may be very short) and the normal cycle starts again (first 2 cycles may be longer than subsequent ones) it is traditional to cover a mare on the 9th day after foaling
There is strong relationship between the day length and the (an)ovulatory period ovulation is minimal or absent in the winter and maximum in the summer
The cyclic corpus luteum begins to regress at 12th day of the cycle, when there is parallel fall in blood progesterone concentration collapsed follicle is recognized as a raised bump on the ovarian surface (usually there is some hemorrhage into the follicle and the coagulum hardens within 24 hours)
Manual rupture of the mature follicle (3-7 cm ) results in termination of estrus within 24 hours a few hours before ovulation the tension in the follicle usually , and the palpable presence of a large fluctuating follicle is a sure sign of close coming ovulation
Cycle length during reproductive season is 21 days (range 20-23 days) length in summer (Jun- Sept) and in spring
Estrus lasts 6 days (3-9 days) longest (7-8 days) in the non-breeding seasonDi-estrus (corpus luteum is fully functional) lasts 15 daysOvulation takes place 24-48 hours before the end of estrus (constant relationship that does not
dependent on duration of cycle or length of estrus) in the ovulation fossaFertilization of the ovum takes place in the oviduct and is possible up to 30 hours after ovulation
only fertilized egg pass into the uterus (non-fertilized ones remain for month in the uterine tubes where they slowly disintegrate)
Transport of the ovum from the ovary to the uterus takes 6 daysImplantation of the blastocyst takes place 2 month after fertilizationFillies are often seen in estrus during their 2nd spring and summer (when they are yearlings), but
under natural conditions it is un-usual for them to foal until they are over 3 years oldDuring estrus, usually a single egg is released and there are slightly more (52.2%) ovulation’s from
the left ovaryTwin ovulation commonly occurs in mare and there is a strong breed influence (common in
thoroughbreds and rare in pony)Ovulation with subsequent formation of corpus luteum does not always occur, and the follicle may
regress or undergo luteinization
8. The estrus cycle in the cow (R&O - 17; CAR - 13)Generally not dependent on the season of the year (poly-estrus)Once puberty (7-18 month) had reached, cyclic activity should persist in cow every 21 days
(range 18-24 days) and in heifer every 20 days (range 18-22 days) except during pregnancy, 3-6 weeks after calving, high milk yield (mainly if there is dietary insufficiency) and with some pathological conditions
Some cows and heifers fail to show signs of estrus (mainly at the first ovulation after pregnancy) but have normal cyclic activity (silent heat or sub-estrus)
Estrus day is called day zeroEstrus duration is relatively short 15 hours (range 2-30 hours) depending on breed, season of
year, presence of bull, nutrition, milk yield, lactation number and the number of cows that are in estrus at the same time)
Ovulation (spontaneous) takes place 30 hours after the onset of estrus (occurs 12 hours after the end of estrus)
Fertilization of the ovum takes place in the oviductThe blastocyst arrives to the uterus at around day 5Pregnancy lasts 279-290 days and the interval from calving to first ovulation varies greatly (depends
on breed, nutrition, milk yield, season, presence of sucking calf)
9. The estrus cycle in the ewe and goatEwe (R&O – 27; CAR – 97)Seasonal poly-estrus 8-10 recurrent cycles of 17 days (14-19 days) in the transition period
(end of summer) shorter cycles (<12 days) are commonThe stimulus for onset of sexual activity is mainly shortening of daylight (while long days induce an-
estrus), but also breed (some are more resistant to light variations), management (male effect) and social cues the first estrus of the season is commonly “silent”
Breeding season is influenced by latitude (shortens with increase of latitude lines at the equator ewe may bread at any time of the year, while as we proceed to the northern or southern hemisphere the breeding season is restricted and distinct with a prolonged an-estrus after parturition)
Breeding season is also influenced by the breed and age (shorter in lamb and yearling).Estrus cycle can be divided (as in other species) into 2 phases:
Follicular phase (3-4 days)Luteal phase (13 days) = maturation of the corpus luteum and high levels of
progesterone (max. peak 6 days after ovulation)Estrus in mature ewe lasts 30 hours (18-72 hours), at least 10 hours less in immature ewe) and in
Merino sp. it lasts 48 hours (influenced by age, breed and season) comparing to other Ru female, estrus in ewe is less apparent (may remain un-detected unless a ram is present)
Ovulation (spontaneous) occurs towards the end of estrusOvulation rate (number of eggs realized at ovulation) is influenced by breed, age, reproductive status
(dry or lactating), season of year, nutritional state and body conditionAn-estrus (cycles stop) starts with pregnancy and lasts for some time after the pregnancy (post
partum or lactation an-estrus) and its length varies with breed, management and date of parturition (seasonal and post partum an-estrus can have additive effect) post-partum an-estrus is mainly influenced by anti-gonadotrophic effect exerted by the suckling lamb, so it normally disappears shortly after weaning (but even in the absence of lambs, as lambs reared with milk replacers, there is a period of post-partum an-estrus period
Pregnancy lasts 5 month (145-152 days) depending on breed, gestation number (parity) and liter size the first 1/3 is luteo-dependent, but after 50 days of pregnancy progesterone is mainly produced by the placenta (so ovariectomy or administration of luteo-lytic doses of F2 do-not terminate pregnancy during the last 2/3 of gestation)
Goat (R&O – 29; CAR - 115)Seasonal poly-estrus (slightly longer then in ewe) 19-21 (<12-26) days (irregular in the beginning
of breeding season) short cycles are related to season of year, onset of estrus season or transitional period, buck effect and early post-partum periods
Breeding season is influenced by genetics (mainly), environment (temp., photoperiod) and latitude (at the equator may bread at any time of the year, while as we proceed to the northern or southern hemisphere the breeding season is restricted)
Estrus lasts 30-40 (22-60) hours and can be divided (as in other species) into 2 phases:Follicular phase = 3-4 daysLuteal phase = 17 days
Ovulation occurs 12-36 hours after onset of estrus and their number varies from 1-4 per cycle (with reduced kidding rates due to fertilization failure and embryonic mortality)
Pregnancy lasts 5 month (144-151 days) the female depends on the luteal production of progesterone throughout gestation, and any interference of the corpus luteum function at any stage of gestation will terminate pregnancy (abortion)
Post-partum an-estrus or the interval between parturition and 1st post-partum estrus varies among breeds, lactation length, management and nutritional condition varies from 5-6 weeks (or even less) up to 27 weeks
10. The estrus cycle in the sow (R&O - 29; CAR - 83)Poly-estrus (domestic sow) or seasonal mainly in autumn (wild sow)Photoperiod influences also domestic sow an-estrus is more common in summer
lower ovulation rates are more common in summer it is possible to decrease the interval from weaning to
estrus by artificially reducing the day length (from 23.6 to 5.7 days)
The recurrent cycles are interrupted by pregnancy and lactation (during lactation, the physical stimuli of suckling causes heat to be delayed, but many sow show an an-ovulatory estrus 2 days after parturition)
The cycle lasts 21 days (18-24 days)Estrus lasts 53 hours (2-3 days)Ovulation (spontaneous) occur between 38-42 hours after the onset of estrus (last 1/3 of estrus)If satisfactory food is available for young piglets, the optimum weaning age is 5-6 weeks, follicular
growth is accelerated and estrus can be expected within 4-6 days (although weaning at 3 weeks is possible, the disadvantages are that the following heat will be delayed or not show so well and cysts are likely to develop in the ovaries)
Fecundity (fertility) is best from 4th-7th gestationCross breeding of in-bred lines and high energy diets for 11-14 days before the expected estrus
increases the ovulation rate continuation of such diets after mating increases embryonic lossMain differences between wild and domestic sow:
Domestic pig European wild pigNumber of corpora lutea 10 – 20 4 – 6Intra-uterine loses (%) 30 13Gestation length (days) 114 119Average litter size 12 5Number of parturition/year Up to 2.5 1-2
The main factor for maintenance of pregnancy is the level of progesterone (min. 6 ng/ml is required), which mainly originates from the corpora lutea
In sow, prostaglandins do-not have an effect on developing corpora lutea until 12 day of the estrus cycle from this day until parturition prostaglandins can be used for induction of abortion or parturition
11. The estrus cycle in the bitch and queenBitch (R&O- 30; CAR - 129)Mono-cyclic only one estrus during each breeding season
differ from polycyclic species in that there are no frequent, recurring periods of heat all bitches have prolonged period of an-estrus or sexual quiescence between
successive heats irrespective if they have been pregnant or not the average interval between successive estrus periods is 7 (5-10) month (but it is
variable in collie it is 37 weeks, in German shepherd it is 26 weeks and in other species it is between these 2 figures)
mating does not appear to influence the interval, although pregnancy (63 days = 54-72) causes some increase (increases in 28 days on average)
No seasonal effect on reproduction (there is a fairly even distribution cycles throughout the year)The cycle is traditionally divided into 4 phases:
Pro-estrus = have true pro-estrus (vulval edema, swelling and bloody discharge)= female is attractive to male, but will not accept him= lasts 9 days (2-27 days)
Estrus = vulva becomes less edematous and the discharge becomes clearer, less bloody and smaller in amount
= accept male and adopts breeding position= lasts 9 days (3-21)
Met-estrus = this stage starts when the bitch ceases to accept the male= duration is not clear (some say it ends when the corpora lutea have regressed at
70-80 days, while others say it ends when the endothelium is repaired at 130-140)
An-estrus = no external signs (the same is true after parturition following a normal pregnancy)= lasts 3 month before the bitch returns to pro-estrus
Ovulation occur 1-2 days after onset of estrus (although some follicles continue to ovulate up to 14 days later)
Fertility declines from 7 years of age onwardsSplit heat = seen in puberal but not in mature ♀ = swelling of vagina + discharge → regression (an-
ovulatory) → “true” heat (ovulatory)
Queen (R&O- 35; CAR - 163)Seasonally poly-estrus but under modern housing conditions they frequently cycle regularly all year
(constant 14 hours of daylight) sexual activity of free living cats is photo-period-dependent (increasing daylight length 1st estrus usually soon after the shortest day of the year)
Cycle lasts 13-15 days (10-22 days) ovarian activity (onset and duration) depend on daylight length
Cycle show more variation in pedigree cats = longhair cat may have only 1 or 2 cycles per year= oriental cat longer estrus period (reduced inter-
estrus interval)Pro-estrus estrus met-estrus di-estrus (short period of sexual in-activity) repeated until the
end of the breeding season and the last di-estrus of the season is followed by an-estrus (a long period of sexual in-activity) which lasts until the first pro-estrus of the next season
Pro-estrus lasts 1.5-2 days ♂ are attracted to non-receptive ♀ characterized by behavioral changes as rubbing the head and neck against objects, constant vocalization, mating posturing, rolling, Lourdes’s (lowers her front quarters and extends her hind legs), tail is erected and slightly to one side and occasionally slight serous vaginal discharge
Estrus lasts 4-10 days ♀ will accept ♂ in the presence of ♂ it will last 4 (3-6) days, and it extends if ♀ is not-mated
Ovulation is not spontaneous induced naturally by mating and artificially by stimulation of the cervix or hormone administration occurs 27 (24-30) hours after mating the same signs as in pro-estrus, but much more exaggerated (rapid rise in estrogen concentrations), ♀ may urinate more frequently, be more restless (more active)…
Di-estrus lasts 8-10 days sexual inactivityAn-estrus lasts 3-4 month prolonged sexual inactivityEstrus stages can-not be reliably identified by vaginal cytologyParturition (63 days = 61-69 days) may be followed by pro-estrus or a period of an-estrus on
average, queens will call 8 weeks after parturition (range from 1-21 weeks) the interval depends on the weaning age of the litter and in cats with a non-breeding season – on the time of year when kittens are born
Pseudo-pregnancy (lasts 36 days) can occur following any non-fertile mating (it is difficult to be sure that conception and resorption of fetuses have not-occurred) or if ovulation is stimulated artificially
12. Duration of estrus and optimal breeding time
Species Cycle type Cycle length Duration of estrus
Optimal breeding time
Horse Seasonally polyestrus (early spring to summer)
19-26 days 6 days Last few days, should be bred at 2 days interval
Cattle Polyestrus all year 21 days 18 hours Insemination from midestrus until 6 hr after end of estrus
Sheep Seasonally polyestrus (early fall to winter)
16.5 days 24-48 hours 18-20 hr after onset of estrus
Goat Seasonally polyestrus (early fall to winter)
19 days 2-3 days Daily during estrus
Pig Polyestrus all year 21 days 2-3 days 24 hours after onset of estrusDog Un-seasonally
Monestrus 3.5-13 month 2-21 days From day 2 of estrus and on
alternate days thereafter until end of estrus
Cat Induced ovulation seasonally polyestrus (spring and early fall)
14-21 days 6-7 days Daily from day 2 of estrus
13. Uterine and vaginal changes during an estrus cycle Mare (R&O - 10)
Uterus Cervix Vagina SecretionPro-estrus Vascularity , tone
( development of corpus luteum diminish when the c.l.regresses)
Vascularity , relaxation and dilation
Vascularity
Estrus No increase in tone Very relaxed (its protrusion can be seen lying on the vaginal floor with its folds edematous and it is soft and broad on per rectum palpation)
Walls are glistening with clear lubricant mucus
Clear lubricant mucus
Met-estrus Gradual reversion to di-estrus appearanceDi-estrus Pale pink and
flaccidPale pink, small, constricted and firm (narrow, firm tubular structure on rectal palpation)
Pale pink Scant and sticky
An-estrus/ Pregnancy
Flaccid Constrict and gradually turns away from the midline (narrow, firm tubular structure on rectal palpation)
Scant and sticky
** Fertilization of the ovum takes place in the oviduct and is possible up to 30 hours after ovulation only fertilized egg pass into the uterus (non-fertilized ones remain for month in the uterine tubes where they slowly disintegrate)
Pro-estrus Large number of RBC High, squamous, stratified epithelium the stratum corneum and the layers immediately beneath it are lost by desquamation, leaving a low, squamous epithelium 1-3 weeks after the heat ends, the epithelium is converted to columnar epithelium
Epithelium and lamina propria are infiltrated by a large number of neutrophil
Endometrial glands are loosely coiled with very obvious lumina and deep epithelial lining
Estrus RBC number , superficial cells from the stratified squamous epithelium (as anuclear cells, pyknotic nuclei, large intermediate cells) in estrus end appear polymorphonuclear neutrophils
Met-estrus Polymorphonuclear neutrophils become dominant
(+Pregnancy) Higher columnar epithelium
than during an-estrusNeutrophils escape to the
vaginal lumen
Endometrial glands become larger, the coiled parts (in the basal layer of endometrium) are more tortuous and the lumina is smaller
An-estrus Nucleated basal and intermediate cells of the stratified squamous epithelium and a few Ne
2-3 layers of low columnar, cuboidal epithelium
*Stained with simple (as Leishman) or tri-chrome stains (as Shorr)**Can be used to determine the stage of the estrus cycle***Endometrium = 98 days after onset of estrus (met-estrus) desquamation of endometrial
epithelium at 120-130 days restoration by proliferation of cells from the cryptus of the endometrial glands
14. Ovarian changes during an estrus cycle (R&O – 10, 19, 28-30)
Mare (R&O – 10)During an-estrus, ovaries are small, bean-shaped and measure 6 cm from pole to pole, 4 cm from the
hilus to the free border and 3 cm from side to side During pro-estrus, ovaries may be of medium size and knobby due to numerous follicles of 1-1.5 cmJust before onset of heat, several follicles enlarge (1-3 cm)By the first day of estrus one follicle is considerably larger than the remainder (2.5-3.5 cm)During estrus, there are large variations in size depending on number and size of follicles (ovaries of
thoroughbred may contain 2-3 follicles each of 4-7 cm which gives it a huge size) → follicles mature, enlarge (3-7 cm) and rupture (follicle tension a few hours before ovulation) →
During diestrus, there is an active corpus luteum and the other follicle regress, ovary may be only a little larger than in an-estrus (no follicles larger than 1 cm are present)
The collapsed follicle is recognized as a raised bump on the ovarian surface (usually there is some hemorrhage into the follicle and the coagulum hardens within 24 hours)
Fertilization of the ovum takes place in the oviduct and is possible up to 30 hours after ovulation → only fertilized egg pass into the uterus (non-fertilized ones remain for month in the uterine tubes where they slowly disintegrate)
During estrus, usually a single egg is released and there are slightly more (52.2%) ovulation’s from the left ovary
Ovulation with subsequent formation of corpus luteum does not always occur, and the follicle may regress or undergo luteinization
Cow (R&O – 19)In dairy Bo 60% of ovulations are from the right ovary (in beef Bo the difference is not so great)Follicles grow in 2 (or 3) waves (influenced by genetic or environment) → on 3rd-4th day and on 12th-
14th day of the cycle → a normal follicle (9–13 mm) from the first wave was present from 5th to 11th day and than undergo atresia and a second normal follicle (9-13 mm) from the second wave was present from 15th to 20th day and than undergo atresia
The ovulatory follicle is selected 3 days before ovulation = follicles grow under the influence of FSH → one follicle obtain dominance and subsequently ovulate (un-known intra-ovarian mechanism which does-not involve FSH suppression)
During di-estrus several large follicles (7–15 mm) will be found → these follicle do-not alter the ovaries external texture, but do cause some overall variations in ovarian size (the ease of palpating them rectally will depend upon size, degree of protrusion and relationship to the corpus luteum)
During pro-estrus and estrus the selected follicle enlarges and ovulates (ruptures) when it has attained a size of at least 19 mm (on rectal palpation of the ovaries, it is usually possible to detect the ripen follicle as a slightly bulging, smooth, soft area on the surface of one ovary)
Ovulation may occur from any aspect of the ovarian surface, and it influences the shape of the ovary → usually it is in an a-vascular area of the follicular wall so hemorrhage is not a feature of Bo
ovulation (although there is marked post-ovulatory congestion around the rupture point and some- times a small blood clot is present in the center of the new corpus luteum)
Ovarian size = depend mainly on the period in the estrus cycle and whether or not it contains active corpus luteum
= the presence of follicles almost does-not alter the size = in most cows examined between the 6th and 18th day of di-estrus, one ovary is
distinctly larger (CL projects from one of its surfaces) than the other (flat from side to side)
= during first 4-5 days of the inter-estrus phase, there will be relatively little variations in
= during estrus, there will also be little difference in size (the ovulating ovary is only slightly larger than the other) = ovaries of normal multi-parous cow do-not differ greatly from those of heifer but tend to be larger due to progressive deposition of scar tissue and in some cases also to the presence of large numbers of small viable follicles → in mid-diestrus the ovary containing the corpus luteum is plumb like and the other is flattened from side to side = in multi-parous, except corpus luteum (active and regressed) and follicles, there is also old scared corpus luteum of previous pregnancies (white or brownish-white, pin-head-size projection on the surface of the ovary, max. 5 mm = corpus albicans) → it takes this structure several weeks after parturition to regress (brown color and 10 mm ) and it is slowly invaded by scar tissue
Ewe (R&O – 28)Ovaries are smaller than those of a cow and they are near spherical shapeDuring an-estrus their size is 13 mm from pole to pole, 11 mm from attached to free border and
8 mm from side to side → the largest follicle present vary from 2-6 mmAt the beginning of estrus one or more follicle have attained the size of 10 mm, it walls are thin and
transparent and the follicle appears purple in colorThe rupture of the follicle is followed by the elevation of a small papilla above the general surface →
ovulation occurs through rupture of this papilla (about 24 hours after estrus onset) → the development of the corpus luteum is similar to that of cow
By the 5th day of di-estrus the follicle is 6 mm , and it attains its max. size (9 mm ) by the middle of the diestrus – when it has central cavity
As diestrus advances, the follicle color changes from blood-red to pale-pink and its size remains constant until the onset of next estrus, where atrophy is rapid and the color changes first to yellow and than to brownish-yellow
During pregnancy the corpus luteum remains 7-9 mm , its color is pale pink and the central cavity disappears (filled by white tissue)
During the an-estrus may occur ovulation with corpus luteum formation but without signs of heat (spurious ovulation)
In twin ovulations the corpus luteum may be on the same or opposite ovaries → the number of ovulations during heat depends on genetics, nutrition and age for example: = hill sheep usually have 1 lamb but is they are transported before the breeding season to low-
land pasture twins become more common= low-land breeds have on average 1.5 lambs per ewe= max. twins when ewes are 5-6 years old, after which it remains constant= primiparous ewe are much less likely to have twins comparing to pluriparous ones= the Border Leicester Lleyn breeds in Britain commonly bear triples, and the Finnish
Landrace and Cambridge breeds produce 2-4 lambs per pregnancy
Goat (R&O – 29)Ovaries are variable in shape (max. 22 mm length) depending on the present structuresThe largest follicle reaches max. 12 mm and often have bluish tinge when they protrude from
the surface → the corpus luteum are pink
Sow (R&O – 29)Ovaries are relatively large and mulberry-like, and their surface is lobulated due to elevations of
large follicles (8-10 mm ) and corpus luteum (10-13 mm )
Except for the follicular stage of the cycle, there is continuous proliferation and atresia of a follicle pool 50 (each 2-5 mm )
Between day 14-16 of the cycle, gonadotropin stimulates selected follicles which are destined for ovulation. It is also associated with rapid atresia of small follicles and blocking their replacement from the proliferating pool (intra-ovarian control mechanism)
The ripe follicle is sea-shell pink with a fine network of surface blood vessels and a vary transparent focus which indicates the site of coming ovulation
Haemorrhagic follicles are common After ovulation there remain a considerable number of follicles of 4 mm , some of which
gradually enlarge to 9 mm (by day 18)After ovulation the ruptured follicle is represented by a congested depression, that soon is covered by
a blood clot (may persist up to day 12) that gives it a conical shape (by day 3) → the clot is replaced by day 6 by a connective tissue plug or by a slightly yellow fluid (may persist up to day 18) → max. size at days 12-15, after which the corpus luteum gradually regresses to the next estrus
Corpus luteum is dark-red up to day 3 → changes to wine-red up to day 15 → as the corpus luteum regresses (days 15-18) the color changes to yellow, creamy-yellow or brown-yellow → remains through di-estrus up to the next estrus and than changes gray, pin-head foci
Bitch (R&M - 33)In young ♀ the ovaries surface is smooth and regular, but in aged ♀ it is irregular and scaredAn-estrus = ovaries are oval and slightly flattened
= 14 mm from pole to pole and 8 mm from the attached to the free border in a medium size bitch
= no appreciable follicles can be seen (only on section the remnants of the corpus luteum are seen as yellow or brown spots)
Pro-estrus = at onset the developing follicles are already 5 mm → progressively enlargeEstrus = 6-10 mm → ovary is considerably enlarged (size and shape depend on the number of ripe
follicles)= owing to the thickness of the follicles wall (hypertrophy and folding of the granulosa cells)
it may be difficult to distinguish between follicles and corpus luteum= prior to ovulation the surface of the follicle show slight raised papule, pin-head size, and the
epithelium covering it is brown (contrasts with the flesh color of the remainder of the follicle)
= ovulation is spontaneous and normally occurs 1-2 days after onset of acceptance= most of the follicles rupture over a period of 48 hours= the oocyte is capable of being fertilized for up to 108 hours after ovulation
Corpus luteum = first contains a central cavity → by the 10th day after ovulation it becomes filled by compact luteinized cells and it attains its full size (6-10 mm)
= as a rule, an approximately equal number of corpus luteum are found in each ovary, although occasionally there are wide differences (the numbers of fetuses in the respective cornua in pregnancy frequently differs from those of the corpus luteum on the ovaries on the respective side) → embryonic migration into the cornua on the opposite side is common
= on section the corpus luteum is yellowish pink → = it remains un-changed in non-pregnant bitch until about the 30th day after ovulation
→ slowly atrophies and viable vestiges may be present throughout an-estrus= throughout pregnancy, the corpus luteum persist at their maximum size, but regress
rapidly after parturition
15. Detection of estrus and ovulation
Mare (R&O – 15, CAR - 62)Observation of behavior
♀ in estrus will seek contact with other horses and especially ♂ (♀ not in estrus will reject any advances of other horses) → since ♀ not in heat will usually violently oppose the advances of a ♂, “trying” should be done over a gate, box-door or fence
♀ will put her head next to the head of the ♂Standing reflex when the ♂ nips at herUrinate frequently and there will be a winking motion of the vulva (repeated exposure of
clitoris)A clear thin mucus can be excreted from the vulvaVulva is slightly edematousRaises her tail to one side**signs are more clear when ♀ is brought into contact with ♂ or teaser (in the absence of ♂ or
other horses the signs are much less clear)**signs are vague at the onset of estrus and will become clearer and more intense towards the
moment of ovulation**in the presence of a foal, the maternal instinct may disturb the normal estrus behavior
Rectal palpation, preferably with the help of ultrasound (detection of follicular activity in the ovaries)with the development of the corpus luteum the uterus increases in tone and thickness (both
diminish when the corpus luteum regresses)at estrus there is no increase in toneduring an-estrus and first few days after ovulation the uterus is flaccidduring di-estrus, pregnancy and pseudo-pregnancy the cervix is identified as a narrow, firm
tubular structure → at estrus, the cervix is soft and broadProgesterone testing → during the period of estrus plasma progesterone level will be below 1 ng/ml
Cattle (R&O – 18, CAR - 18)Estrus signs = Standing when mounted (most reliable indication)
Swollen vulvaHyperemic vaginal mucosaClear and elastic mucous vaginal dischargeRuffled tail-head, possibly with minor skin lesionsRestlessnessGroup formationChin rubbingFlehmen (urine or perineum sniffing)Licking, pushing, fighting, mounting other animalsLordosisReduced feed intakeReduced milk yield
**blood in the vaginal mucus is a sign that the cow was in estrus about 2 days beforeObservation 3 times a day for 20 minutes each time (early in the morning, evening and around 10pm)Teaser bull 3 times per day = vasectomized bulls, testosterone-treated cows → will mount cows in
heat (aggression, favoritism thus ignoring other cows in heat and vasectomized bulls have the ability to spread venereal diseases)
Heat mount detectors glued on the mid-line of the back, just in front of the tai head (conflicting results, losses, poor performance in cold weather and high proportion of false positive reactions – when animals are kept in high density)
Tail paints = a strip (20x5 cm) of enamel paint on the coat that covers the points near the tail-head which will be rubbed by mounting animals (high proportion of false positive reactions – when animals are kept in high density)
Pedometers = count the number of steps → cows are more active at estrus Rectal palpation, preferably with the help of ultrasound (detection of follicular activity in the ovaries)Difficulties in estrus detection= cycle length vary from 18-24 days
= the cow may show signs for only a short period= sexual activity often occurs at night= sexual behavior of cow in heat shows individual variations= tied housing (better detected in loose housing)= mistake in identification of the cow
Sheep (R&O – 27, CAR - 102)***While estrus detection is almost never used in natural mating, it is essential for artificial
insemination or hand mating since they are successful only if performed at a fixed time in relation to ovulation or onset of estrus
Standing reflex = female allows male to mount (the only sure sign)Aproned (a piece of leather suspended under the belly of a ram in front of the prepuce to prevent
mating when the ram is used as teaser) and vasectomized teasers → if artificial insemination is done by using fresh semen, these methods can only be used only in very large flocks exploited in special conditions and performed only during the breeding season (since they are time consuming)
An alternative to estrus detection is control or synchronization of estrus → shortens the time necessary to inseminate a whole group or flock, reduces labor…..and allows breeding during the an-estrus season
Goat (R&O – 29, CAR - 118)Detection of heat is difficult in the absence of male → in the presence of male pheromones
(can be transferred from the scent gland onto a cloth) will intensify the signs Estrus symptoms are preceded by pro-estrus (lasts 1 day) where the buck closely follows the doe
but she will not allow him to mountStanding reflex = female allows male to mount (the only sure sign)♀ actively seek the presence of ♂ when in estrusThe odor of the buck has stimulating effect on the expression of estrus ♂ may exhibit flehmen reaction (urine or perineum sniffing), flick (move from side to side) his
tongue and strike the doe with a forelimbThe vulva show some edema, hyperemia and mucus dischargeThe tail is twitched rapidly from side to side and up and downRestlessnessMore vocal (bleating)Reduced appetite and milk yieldUrination near the buckSome does show no signs other than limited tail wagging and standing for mounting by the buckDoes will occasionally stand for mounting by other doesAs heat progresses, a variable amount of transparent mucus is visible in the cervix and on the floor of
the vagina → the mucus turns cloudy (best time for conception) → cheesy white (end of heat)Estrus is occasionally observed during pregnancy
Sow (R&O – 29, CAR - 86)Reddening and swelling of the vulvaStanding reflex = estrus can be divided into 3 parts → during the 1st and last parts (ovulation occur in
the 3rd period) only a ♂ can induce the reflex, while in the 2nd part a man can provoke this reflex by the back pressure test (the use of synthetic boar aerosol improves the response to this test)
Behavior = restlessness during feeding= not settling down after feeding= frequent urination of small quantities= cocking (erect) position of ears after sniffing the vulva of other animals or smelling a boar= saw in pro-estrus sniff and try to ride other saws or will be recipient to such attentions= in presence of ♂, saw in pro-estrus will sniff its testicles and flanks and may try to
mount him but will refuse to be mounted= at the height of estrus saw assumes a stationary, rigid attitude with her ears erected and
she is quite ignores her environmentPressing firmly (using both hand palms) the loin of the sow → estrus sow will stand motionless with
erect ears (sows not in heat will object to this approach)Salivary pheromones (released from sub-maxillary glands) of a boar (10 month or more in age) or
housing the ♀ in the same pan as pre-puberal gilts or recently weaned saws → stimulates estrus and estrus behavior
Vulva Mucus on vaginal mucosa Standing reflexToo early Heavily red + swollen Hardly any Negative back pressure testIn time Moderately red + swollen Present Positive back pressure testToo late No redness + swollen Sticky Negative back pressure test
Bitch (R&O – 31, CAR - 136)Observation = Slight swelling of vulval lips (precedes the beginning of bleeding by several days)
Bleeding is max. during early pro-estrus → continues at this level into the early part of the true heat
Standing in mating position with her tail slightly erected or held in one side (only in estrus)
Vaginal cytology = (smear of vaginal cells) can be used to detect pro-estrus, estrus and met-estrus, but in fact it can only be relied to detect the time of ovulation retrospectively (in the past) → this is because the 1st day of met-estrus is the only stage which can be pinpointed precisely (dramatic fall in % of superficial cells and re-appearance of WBC) → if these changes are seen it can be said that ovulation occurred about 6 days earlier (to late if the aim is to get the bitch pregnant)
Vaginoscopy = at the time of ovulation, skilled observer will note the onset of wrinkling effect (wrinkling become very obvious 4 days after ovulation → most critical time for mating)
Measurement of hormones levels =
= LH = It is common to regard the pre-ovulatory LH peak as the central event in the cycle. Most of the important events that occur in the cycle are closely synchronized with this event.
Event Time post LH peak (days)Ovulation 2Oocyte maturation 4-5 (i.e. 2-3 days post ovulation)Peak fertility 0-5Implantation 18Parturition 64-66
LH levels are raised only transiently over a period of 1-3 days, frequent blood sampling (at least every day) would be required → therefore, the LH levels do not provide a practical answer in detection of the best time to mate bitches
= Progesterone = detected within half an hour in a drop of plasma
Progesterone LHLevel increase LH peak2-5 ng/ml 2 days after LH peakPeak levels 13-28 days after LH
peak
Progesterone Mating<5 (ng/ml) No mating – wait for next sampling (2 days later)5-6 (ng/ml) Mating within 33-57 hour after sampling6-12 (ng/ml) Mating the next day>12 (ng/ml) Mating the same day
Queen (R&O – 36, CAR - 167)Estrus stages can-not reliably be identified by vaginal cytologyBehavior = Pro-estrus = ♂ are attracted to non-receptive ♀
= behavioral changes as rubbing the head and neck against objects, constant vocalization, mating posturing, rolling, lordosis (lowers her front quarters and extends her hind legs), tail is erected and slightly to one side and occasionally slight serous vaginal discharge
= Estrus = ♀ will accept ♂= ovulation is not spontaneous → induced naturally by mating and artificially by
stimulation of the cervix or hormone administration → 27 (24-30) hours after mating → the same signs as in pro-estrus, but much more exaggerated (rapid rise in estrogen concentrations), ♀ may urinate more frequently, be more restless (more active)…
16. Neuro-hormonal control of the estrus cycle (CAR – 1-8)General = the reproductive process is regulated by 2 systems → endocrine and nervous systems : Nervous = Stimuli from environment (light, sight of other animal of the same spp, pheromones,
tactile)↓
Stimuli transmitted to the brain (by optic, olfactory and sensory nerves)↓
The brain translate the information and if necessary reacts by sending nervous impulse (through nerve fibers) to target organs
Hormonal = Regulatory system that sends information by means of chemical messengers (hormones) → this system is regulated by feedback loops and impulses from the nervous system
= Hormones = chemical substances, produced in a gland or tissue in the body, which provoke a specific reaction in hormone sensitive tissue (target cells have hormone- specific receptors)
= Hormone receptors = A unique molecular structure in/on the cell with a high and specific affinity for a particular hormone → after binding to the receptor the message can pass on → leads to cell specific response (generally involves activation or inactivation of enzymes in the target cells)
= These receptors have 2 functions:1. Recognition of the specific hormone by the target cell2. Translation of the hormonal signal into a cell-specific response
= Autocrine acting hormones = the producing cell is also the target cell= Paracrine acting hormones = the hormone influences a neighboring cell or organ
(exocrine) = Endocrine h.= Secreted by an organ or a group of cells → released directly into the
blood → reach target cells or organs= Their effect vary according the number and type of receptors of a target
cell → the formation and degradation of receptors is a dynamic process (number and type are not fixed)
** the function of one hormone in a cell can be the induction or degradation of receptors for another messenger)
** receptors can be blocked by an excess of hormones** extra-stimulation by a normally highly effective dose of
hormones → no further effect= Exocrine h.= secreted externally via a duct → excreted by GIT, urine,
skin….. before reaching the target organs= Most receptors need a second messenger to transmit the message for example cyclic-
AMP:Chemical messenger binds to the receptor
↓Activate the adenylate-cyclase-system situated in the cell membrane
↓ATP is converted into cyclic-AMP (the second messenger)
↓c-AMP activates an inactive cAMP-protein-kinase-A that splits up into an active catalytic unit and a regulatory unit
↓The active catalytic unit of the protein-kinase stimulates the phosphorylation of a protein or enzyme which brings about the cellular effect
↓
The phosphorylation brings about the cellular effect (as protein synthesis, growth or hormone secretion)
Neuro-hormonal control of the estrus cycleCNS receives information from the environment of the animal (visual, olfactory, auditory, tactile)
↓Stimuli pass to the hypothalamus in the ventral part of the brain
↓CNS stimulate the hypothalamus endocrine neurons which produce GnRH
↓GnRH is transported via the hypothalamo-hypophyseal portal system to the anterior lobe of the
pituitary gland (in the ventral part of brain)↓
GnRH stimulates the gonadotroph cells which secrete FSH and LHFSH = Stimulates the development of ovarian folliclesLH = Stimulates the synthesis of androstenedione in theca interna of the follicle (from cholesterol)
→ Androstenedione is converted into testosterone↓
Testosterone is aromatized (in the granulosa cells of the follicle) under the influence of FSH to oestradiol-17 (has positive effect on the hypothalamus and pituitary)
The granulosa cells of the follicle also produce the hormone inhibin negative feedback on the FSH release from the pituitary → control follicle development
↓Oestradiol =1. frequency of GnRH pulses
2. induces estrus symptoms (behavioral and physical)↓
Above a certain threshold level of oestradiol, the hypothalamus responds by GnRH ↓
The GnRH causes LH ↓
LH initiates ovulation↓
After ovulation, under the influence of LH, the follicle becomes corpus luteum. The follicle cavity is filled with blood vessels, and the granulosa cells increase in size.
↓The corpus luteum (mainly a secretory organ) produces progesterone and oxytocinProgesterone =1. essential for the normal cycle
2. after conception (getting pregnant) it is the main hormone responsible for the maintenance of pregnancy:
a. GnRH pulse ↓ → inhibits new ovulationsb. prepares the endometrium for the nidation (implantation of the
fertilized ovum in the endometrium of the uterus in pregnancy) of the embryo
c. inhibits un-controlled contractions of the uterine wallOxytocin → plays a role in luteolysis (and also stimulates uterine contraction = parturition, sperm
and egg transport and milk ejection)↓
If the ovum (released from the follicle during ovulation) is not fertilized → the animal does not receive a signal of pregnancy from the embryo → 16 days after ovulation, the endometrium of the non-pregnant uterus releases PGF2
↓PGF2 initiates the regression of the corpus luteum (luteolytic hormone) → the mechanism is not
completely understood, but it includes vasoconstriction (blood supply ↓ to the corpus luteum) and direct effect of PGF2 on the luteal cells
↓As a result of the corpus luteum regression the progesterone concentration in the blood ↓
↓The progesterone block on the release of GnRH from the hypothalamus – disappears
↓Initiates a new follicular phase and the final development of a pre-ovulatory follicle
** Both hypothalamus and pituitary produce hormones and serve as target organ → create a homeostatic feedback system by which most hormones regulate their own rate of secretion
** GnRH, FSH and LH are released in a pulsatile way (released in pulses)** Follicular phase of the cycle = the period of follicle ripening, estrus and ovulation, which is
characterized by production of oestradiole** Luteal phase of the cycle = the period from ovulation until luteolysis, which is characterized by
progesterone dominance
Differences between species in endocrine changes during the cycle (R&O – 16, 26, 28, 30, 34)
MareFSH Biphesic, with 10-12 interval between peaks → 1st peak occurs just after
ovulation and the 2nd in mid- to late di-estrus (about 10 days before the next ovulation)
It has been suggested that this peaks (unique to mare) are responsible for priming the development of a new generation of follicles, one of which will ovulate at the next estrus
LH There is no sudden increase (unique to mare) but a gradual increase → persistence of elevated levels for 5-6 days, both before and after ovulation
Oestrogens Peak values during estrusProgesterone Follow closely the physical changes of the corpus luteum
Cow FSHLH The pro-estrus rise in estrogens stimulates the increase in LH (necessary for
follicular maturation, ovulation and corpus luteum formation → a second less distinct peak 24 hours later
Oestrogens Sudden rise just before the onset of behavioral estrus → pick at the beginning of estrus → decline to basal levels at the time of ovulation → fluctuations during the rest of the cycle, with a small peak in about the 6th day of the cycle (may be related to the 1st wave of follicular growth)
Progesterone The changes mimic closely the physical changes of the corpus luteum → peak at day 7-8 after ovulation → decline quickly from day 18
In a number of cows there is evidence of delay on progesterone production or secretion by the corpus luteum → does no appear to largely affect the fertility of the individual
Prolactin Difficult to obtain since stress induced by restraint for vein-puncture is sufficient to cause a significant rise
Ewe FSH Reaches a peak about 14 hours before ovulation (the same time as LH peak) → a second peak 2 days after ovulation
LH The rise in Oestrogens is followed by a sudden rise of LH → reaches a peak about 14 hours before ovulation (FSH peaks at the same time)
Oestrogens Rise just before the onset of estrus Progesterone Follow closely the physical changes of the corpus luteum, but max. values (2.5-
4 ng/ml) are lower than those of the cowProlactin Fluctuates through the estrus cycle, however it rises during estrus and ovulation
(reflecting the role of this hormone in the formation of the c.l.)
Sow FSH Concentration vary considerably, but there appears some pattern of secretion peak with the LH peak → second larger peak on day 2-3 of the cycle
LH Peak at the beginning of estrus → second peak 8-15 hours after the oestrogen peak → values remain low and fluctuate throughout the rest of the cycle
Oestrogens Starts to rise at the time that the corpus luteum begins to regress → peak about 48 hours before the onset of estrus
Progesterone Fluctuates through the estrus cycleFor the first 8 days after ovulation there is a good correlation between
progesterone levels and the number of corpus luteum, however, by 12 days it is less obvious
Prolactin Peak together with the pre-ovulatory LH → second peak during estrus
Bitch FSH Peak at the same time as the LH peakLH Rise rapidly after the oestrogens rise → peak lasts much longer than that of
other species (peak at the same time as the FSH peak) → ovulation occur 24-96 hours after this peak
Oestrogens Rise rapidly just before the onset of standing estrusProgesterone Differ from other spp. by the persistent high levels of this hormone
Start to rise before ovulation, which confirm the morphological evidence pre-ovulatory luteinization of the mature follicles 60-70 hours before ovulation → this pre-ovulatory rise in progesterone may provide the stimulus for the bitch to accept the male (can be used as a method to determine the timing of artificial insemination, that should not be delayed long after plasma concentrations are >2-3 ng/ml)
Have a negative correlation with prolactin → thus, as progesterone level falls towards the end of met-estrus or pregnancy, prolactin increases
Prolactin Have a negative correlation with progesterone → thus, as progesterone level falls towards the end of met-estrus or pregnancy, prolactin increases
Cat FSH Have not been reportedLH (in the absence of coitus or mechanical stimulation) remains at basal level
during estrus17 β estradiol Levels of above 20 pg. / ml indicate the phase of follicular phase. estrogens Estrogen concentration increase at the time of estrus, from the baseline of
60 pmol / L to peak of 300 pmol / L. Progesterone Remains at basal level during unovulatory estrus cycle.
22 + 160. Reproductive management in cattle (in large scale herds) (CAR – 13, M - 1462)Optimal production of both milk and calves
a. Every cow has to produce 1 live and healthy calf per year (calving interval = 365 days)b. Raise/market 95 calves per 100 cows per year
Reproductive performance can be improved by a. Proper identifying animalsb. Keeping records that enable determination of important herd parameters, such as % calf crop,
pregnancy rate, length of calving season, culling rates, calf mortality, breeding efficiency of bulls and performance production information
c. Meeting the nutritional requirements of various classes of livestock in the heard (emphasizing correlation between nutritional needs and costs)
d. Establishing breeding program for heifer and cowse. Bull selection and reproductive managementf. Immunization programg. Evaluating all abortionsh. Careful attention at calvingi. Providing adequate facilitiesj. Ensuring that calves are well cared at birth and receiving adequate colostrum
Nutrition The limiting nutrient in relating to reproduction in beef is energy (not so important in dairy since
most are fed rations that supply adequate energy during lactation) = a. energy levels before calving influences when the cow returns to estrusb. energy levels after calving influences the conception rate
Feed requirement vary during the reproductive cycle = 1st period = the interval from calving to breeding (82 days) → the period of greatest
nutritional demand since the cow is at max. milk flow and recovering from the stress of parturition → by the end of the period she is expected to breed
2nd period = beef = the interval from re-breeding to weaning the calf (123 days) → cow gain weight while still milking
= dairy = 2nd + 3rd periods overlap → although some gain weight, most high producers lose weight during this 2nd period
3rd period = from weaning to 50 days before calving (110 days) → the period of least nutritional demand = beef = has only to maintain her condition and fetus
= dairy = should gain body weight during the last few month of lactation
4th period = the 50 days preceding calving → during this period occurs 75% of fetal growth (critical stage) and cow condition at calving is critical to re-breeding (the onset of estrus after calving is delayed in cows that lose weight or are thin and not gaining weight during late pregnancy)
Dairy is usually fed for max. milk production throughout her 10 month of lactation → it is assumed that she will loose weight during heavy lactation and regain the loss during the remainder of lactation → the cow should not be overfed during the dry period because of the possibility of fatty liver disease and ketosis during lactation
The amount of cow feed per Kg. of calf weaned is fairly constant, although larger cows require more feed than smaller cows
1st–calf heifers require special attention from both energy and competition (on food) standpoint if they are expected to breed and conceive at the proper time → they are still growing, lactating and may not have the rumen capacity to meet post-calving energy needs on roughage alone → supplement feeding of high-energy high-protein may be required for optimal reproductive potential (in many places calves are also weaned 30-40 days earlier then other cows to allow the heifer more time to grow and recover from lactation)
Protein = cows that give more milk require more feed with higher level of protein (increased milk is produced at the expense of reproduction when feed is not adequate to meet all needs) → the protein requirement of young growing stock and heavy milkers is often a limiting factor, while mature dry cows are often overfed protein and heifers must be fed adequately from weaning to breeding if they are to calve at 2 years of age
Feed must be analyzed to monitor its true nutrient content and actual $$ value → variations in the amount of trace elements, energy, protein…
Thin, old or small cows may not compete favorably with heavier cows within the same heard and often benefit from being fed as separate sub-group
Lactating dairy are usually fed according to milk production → fed concentrate on an individual basis or divided into groups according to milk production and fed complete blend ration
Breeding program If cow is to calve consistently, she must be early with her 1st calf → heifers that are breed at 14
month and calve at 23 month → benefit from getting closer attention by calving before the main herd starts to calve and having the extra time needed to re-breed
In order for a heifers to breed at 14 month she must attain at least 65-75% of their mature weight before breeding → so nutrition is important
The breeding season of virgin beef should start 3 weeks before that of the main herdDairy calve throughout the year so these considerations are not apply to themTo compensate for the greater attrition rate usually expected with virgin heifers, a greater number
should be bred than is needed to maintain or increase heard numbersAn-estrus or irregular estrus cycles may result from poor management, failure in estrus detection,
poor nutrition, disease, injury, silent heat (no estrus behavior), disturbance in endocrine functions, accidental access of bulls to cows (unexpected pregnancy) or failure to keep proper breeding records (the cow can be already pregnant, to soon after calving…)
Estrus detection → systemic program for detection (very important)→ observer familiar with signs of estrus→ estrus detectors = cows or steers give an androgen, bulls altered so they can-
not inseminate, chalk, chemical or electronic activated markers on the tail-head and vaginal probes that measure the electric conductivity of the vaginal mucus
→ rectal palpation = ovaries (mainly in cow with silent heat) estrus is determined by the presence of a palpable follicle, absent or decreased corpus luteum and firm uterine tone
= vaginal mucosa edematous= cervix relaxed and hyperemic= discharge variable amount of clear serous mucus (blood
in the mucus in the immediate post-ovularory period)= vulva swollen
In cows that approach ovulation, the appropriate time can be estimated, and the cow can be bread regardless of whether she shows behavioral signs or not (if the estimation was wrong and the cow show signs a few days later, she can be re-bred)
Synchronization (prostaglandin or its analogs effective only in cows with functional corpus luteum) reduce the dependence on estrus detection:1st dose → animals in days 6-18 of the cycle corpus luteum regresses estrus within 2-7
days, while the → other animals may either been recently in estrus or will be in a few days
2nd dose is given 11 days later (all cows are between days 6-18 of their cycle) → most cows will be in estrus in 3-4 days and ovulate in 4-5 days
Insemination is based on signs of estrus or performed 60 hours (heifer) or 72 hours (lactating cow) after the 2nd prostaglandin inj.
Non-functional ovaries (smooth, small, bean-shaped structures in rectal palpation) may be due to low total energy intake during late winter or drought summer pasture, chronic or severe disease, injury, ovarian tumor, congenital defect (freemartinism, hypoplasia…)…→ usually non responsive to gonadotropin or steroid hormone treatment
Evaluation of fertility Dairy heard =
Parameter ObjectInterval calving–conception (avg. number of days open) <90 daysInterval calving–1st insemination <70 daysConception rate at 1st insemination >60 %Number of insemination per conception <1.5Abortions (between days 45-265 of pregnancy) <3 %Culling due to infertility <5 %Age at 1st calving 24 month
Beef heard → the main source of income are weaned calves =→ short calving season is important
Length of breeding period <63 days% pregnant (35 days after the end of breeding season) >95 %% of calf born alive (of cows confirmed pregnant) >93 %
Breeding =Artificial insemination → used mainly in dairy (less in beef because of technical and cost
problems)→ failure to detect estrus is the main reason of AI failure 50-60 %
conceive in 1st service and the same number on the 2nd service if cows are properly inseminated with good quality semen at the proper time
Embryo transfer is used to increase the number of pregnancy from the most valuable beef + dairy cattle sexing of embryos can be used
Before breeding, the following points should be considered = a. Heifer should be bred according to size and age at puberty → first breeding should be
bred according to size and age at puberty (65-75% of mature weight at 1st breeding)b. Breeding program → artificial insemination or natural service with bulls known to sire
calves that have low birth weight the bull owns birth weight (not his adult weight) is a useful guide
c. Heat synchronizationd. Sufficient skilled labor to breed and assist during calving is essential
Pregnancy detectionRecommended to maximize efficiency in the well-managed herdBeef herds → breeding season (AI or natural) lasts 60-70 days, which gives the cow an average of
2-3 services to conceive → cows that are not pregnant or were bred late should be identified (if kept in the herd, they will disturb the program by calving late in the season and maintenance costs are also significant) by pregnancy determination shortly after the season is over while cows still have plenty of flesh and can be sold with greater profit
Dairy → should be examined within 1 month after calving and again 5-9 weeks after breeding
Embryo death, abortion and abnormal fetal development =May be due to bacteria, virus, molds and other infectious agents that attack the placenta or fetus
Non-infectious abortions = genetic reason recessive or lethal genes, hydrocephalus, ostoperosis (marble bone disease), arthrogryposis (crooked calf syndrome)…
= poisoning excessive nitrates in feed or water, certain pine needles, poisonous plants, mycotoxins (mouldy feed)…
= hormonal imbalance in pregnant dam= injury affecting the pregnant cow= nutritional deficiency mainly vit. A, vit. E, selenium, iodine and Mn
23 + 161. Reproductive management in pigs (in large scale herds) (M – 1485)General
Problems on a farm are usually a combination of genetic, nutritional, environmental, health and management factors → investigation should concentrate on the herd and not individual animal and a certain % of “abnormal” animals or reproductive problems should be expected
Accurate up-to-date records are essential
Reproductive indices used in pig herds
Index Level Interference levelWean to service interval (% of ♀ in estrus by 8 days after weaning) 90 % 85 %Repeated service at 21 days <10 % >15 %Abnormal return to service (25-37 days) <3 % >5 %Multiple mating >85 % <80 %Abortions <2 % >2 %Not-in-pig 1 % 2.5 %Farrowing rate (parturition in Su) >80 % <80 %Live birth/litter 10-12 <8Stillbirths <10 % >15 %Mummies <2 % >2 %Litter scatter (≤ 7 pigs/litter) 10 % 15 %Weaned/litter 9.5 9Pre-weaning mortality <11 % 12 %Litters/sow/year 2.4 ≤2Pig weaned/sow/year 20-22 <19Non-productive sow days 30-50 >60
Selection Gilt → selection is based on growth rate, disease status, sexual development, reproductive history
(dam’s performance as to wean-to-service interval, litter size, milking ability and pigs weaned), conformation and underline (teat number and location)
→ 30-40% are culled because of problems as delayed puberty, failure to conceive, defective teats, locomotor problems or vulval abnormalities (inter-sexuality or genital hypoplasia)
→ pre-puberal gilts are usually fed a grower-finisher ration ad-libitum until they reach 90-110 Kg or are 5-6 month old separated from growing pigs, placed in gilt-pool pens and limit- fed a balanced ration containing 12-16% protein
→ gilt selected for breeding = should reach puberty by 6-8 month and weight 105-123 Kg= should-not have excessively straight legs or musculing= well developed external genitalia by 5 month of age = well developed udders at least 6 pairs of evenly spaced teats
Disease and vaccination program Performance can be influenced by porcine respiratory and reproductive syndrome (PRRS), parvo-
virus, pseudo-rabies, entero-viruses, influenza, brucellosis, leptospirosis and other infectious diseases
The herd should be minimally vaccinated against leptospirosis, parvo-virus (gilts) and erysipelasBrought-in gilts should be isolated for 45-60 days, during which serologic tests should be
performed to minimize the number of days for introduction of these gilt, the last portion of the isolation period can be used for acclimatization to the herds residence pathogens (through the introduction of cull sow, market hogs and manure exchange and/or feedback)
this natural exposure to endemic herd pathogens can provide essential protection against diseases)
Puberty Early puberty reduces production costs1st estrus occur between 5-8 month of age depending on the genotype, liveweight, nutritional
status, season and management Management = “boar effect” (most influencing management factor) is strongest when ♀ are
exposed to sight, sound, touch and smell of a mature boar (direct contact decreases as the number of senses stimulated by the boar decreases) → exposure of peri-puberal gilts (5-8 month) to a mature boar for min. 10-15 minutes provides an adequate stimulus
= cross-breeding= changes in housing (confinement to outside pens and vice versa)= forming new groups by mixing gilts from different pens
Gilts are-not served until their 2nd or 3rd estrus to ensure max. ovulation rate and thus litter sizeCulling criteria= gilts in which 1st estrus does not occur by 8 month of age if inj.
gonadotrophins are used to bring these gilts into estrus, the progeny shouldn’t be kept for breeding
= gilts that have been serviced for 3 consecutive heats and do-not conceiveEstrus synchronization= adding progestogen (any substance having progestetional activity) to the
feed (as allyltren-bolone at 15-20 mg/day for 10-18 days) → estrus will occur in 60-80% of the gilts 2-8 days after the last feeding
= prostaglandin’s can also be used as an abortifacient (induce abortion) to synchronize estrus when administration after day 12 and before day 55 of gestation gilt come to heat 4-7 days later
Estrus Usually an-estrus during pregnancy, but many show a non-ovulatory estrus 3-4 days after
parturition (most likely due to residual effect of feto-placental estrogens in the presence of low progesterone)
Ovulatory estrus is usually not-seen during lactation , except under conditions of group rearing, high feed levels or boar effect → partial weaning or gonadotropin treatment can induce estrus during lactation, but the results are inconsistent and not economic
Normal uterine physiology is established by 20-25 days post-partum, and most sow exhibit estrus 3-7 days after weaning
Estrus in gilts and post-weaning an-estrus sow can be initiated with exogenous hormones, but these hormones interfere to the natural selection for reproductive efficiency → these hormones should not be used as a long-term solution to address reproductive in-efficiency in a herd
Estrus lasts ~36-48 hours in gilt and 48-72 hours in sow (cycle lasts 18-24 days = 21 days on average) → time of estrus after weaning and duration of estrus in sow are influenced by length of lactation, nutrition, body condition, genetics and other management factors
During ovulation (occur mid to late estrus),~15-24 ova are released → ovulation rate increases over the first 3 gestations, so the 4-6 litters tend to be larger in number
Ovulation rate can decrease when ♀ are under-nourished → gilts should be on full-feed diet (recently weaned sow should be fed with an energy-dense diet until after estrus and breeding) and if not, increased energy intake for 10 days before estrus (= “flashing”)
The primiparous (a ♀ which had one parturition) sow mast support her own growth as well as maintenance and lactation demands while her feed intake capacity is not yet fully developed → this problem can be avoid by breeding only gilts in good condition, not-overfeeding during the first gestation, encouraging energy intake during the first lactation (ad libitum feeding, high- energy diets, wet feed and avoiding high temp. in the farrowing room)
Early weaning (as early as 10 days pot-partum) can result in post-weaning an-estrus → to minimize this effect, it is recommended to wean primiparous sows not less than 14 days into lactation
wean sow in 2nd lactation not less than 12 days -“- wean sow in 3rd or more lactation not less than 9 days -“-
Factors affecting ovarian activity in pigs
Proved or suspected factors Stage of breeding affectedPuberty After weaning After service
= used in smaller farms and works best in a pen of pigs in various stages of estrus= with a group of recently weaned sows this method is less desirable because their
estrus may occur close together and lead to over-use of the boarHand mating = supervised natural mating
= ♀ is usually mated twice during the estrus 1st service on the 1st day of standing estrus and the 2nd – 24 hours later
= many commercial producers breed the ♀ once daily as long as she will accept the ♂
= the use of 2 different boars can increase the number of pigs per litter by one but may mask infertility in one of the boars
Artificial insemination = heat detection is performed 1-2 times per day: A. If performed 1 per day =
Gilts 2-4 hr. after onset of standing heat and again 12-16 hr. laterSow 12-16 hr. after onset of standing heat and again 18-24 hr. later
B. If performed 2 per day = Gilt 12-14 hr. after onset of standing heat and again 12-16 hr. laterSow 24 hr. after the onset of standing heat and again 18-24 hr. later
= the recommended dose is ≥2 x 109 sperm in 60-100 ml (total sperm numbers in a dose of semen depends on quality and storage time)
Boar should not be over-used =
Boar Boar-to-sow ratioIf sow are weaned in groups Young 1:2
Mature 1:4Hand mating Mature No more than 2 breeding per dayNatural service 1:16–1:25AI 1:100–1:125
Pregnancy Sperm cells reach the oviduct within 30 min. of mating, and fertilization occur within 2-6 hoursFertilization rates approach 100% in sow, but embryo mortality up to 30-40% accounts for the
usual litter size of 10-12 pigs
Retained dead fetuses become mummified and are usually expelled with normal developing fetuses at the time of farrowing → a normal loss of <10% of the fetuses can be expected
The average gestation length is 114±2 days and is shortened in sows with large littersThe embryo is at greatest risk of dying the first 30 days → efforts should be made to avoid stress
during this critical period (overfeeding, heat, handling, moving, immunization) =
= pregnancy of <16 days are especially sensitive to heat stress= avoiding exposure to other animals reduces disease risk= if the gilts have been flushed for breeding, the feed intake should be reduced to the limit
feeding levels of ~2 kg immediately after breeding to avoid embryo loss due to high energy intake
= farrowing (carrying) less than 5 piglets is indicative of embryo death after the time of attachment (a minimum of 4 embryos must be present at the time of attachment for pregnancy to continue)
= to increase colostral antibodies, the gilt or sow can be immunized during the last 6 weeks of gestation → immunization program can include vaccination against transmissible gastroenteritis, E. coli, atrophic rhinitis, erysipelas and other vaccines according the disease situation in the individual farm
Pregnancy determination Female does not return to estrus in 18-25 days (this is 75-85% accurate)Ultrasonography = generally used at 30-75 days for determination of pregnancy
3 types can be used:a. pulse echo (A-mode) = amplitude depth = emitting ultrasound waves from a hand-
hold transducer placed on the skin in the flank area → reflected waves from the fluid- filled area (developing fetus) are picked up by the transducer and converted into either audible or visual signal
b. Doppler = detect changes in sound frequency (fluid movement) using an audible signal
c. real time = involves visualization of a two-dimensional image on a screen directly under the transducer → can be used as early as 18 days after breeding
Rectal palpation can be used to confirm pregnancy >35 days gestation → the examiner palpates for fremitus, size, position of the medial uterine artery in relation to the external iliac artery, tone and tension of the cervix and weight and content of the uterus
Test Days after service CommentsEarliest Latest Optimum
External physical signs
42 Term >55 (gilts)>84 (sows)
Inexpensive confirmation of late pregnancy
No return to estrus Daily testing 18-
25
--- Daily testing 18-
30
An-estrus and delayed returns result in problems
Rectal palpation 18 Term 28-term Gilts to small – can check genital organs of empty sows
Blood progesterone 17 Term 17-20 False positive can be a problemEstrone sulfate 18 77-term 25-29 Also useful to diagnose embryo
deathA-mode ultrasound 23 85 30-70 Quick, easy test but false positive
a problemDoppler ultrasound – uterine artery pulse
21 Term 30-40 Prolonged use distressing to ears
Doppler ultrasound – fetal pulse
28 Term 42-term Can confirm fetal viability and predict farrowing date
Real-time ultrasound 18 Term 24-term Can detect mummified fetuses, fetal age and health information
Parturition Piglets are usually delivered at frequent intervals (15-20 min.) The stillbirth rate is usually 5-10% → intra-uterine death is usually due to infection, incorrect
position in the uterine horn during delivery, anoxia (umbilical cord ruptures or constricted or when there is a delay in birth canal), low temp. in the farrowing house, low hemoglobin levels (<0.9 g/l) in the sow and prolonged parturition time (exhaustion, uterus atony or dystocia) → assistant can be provided in the form of oxytocin inj. (10-30 IU), manual removal of piglets and walking the sow for a few moments (assisting delivery can increase the number of pigs born a live in about 1 per sow)
Farrowing can be induced by IM inj. of 10-15 mg PGF2 (or synthetic analog) → 80-90% farrow 18-36 hours later (most within 22-32 hours) if the PGF2 is given at 112-113 days of gestation (used so most farrowing will occur during normal working hours, avoiding weekends/holidays)
By inj. 20 IU of oxytocin 15-24 hours after the PGF2 inj. we can concentrate the farrowing into a shorter period → shortens the interval to parturition but can increase dystocia incidence
Dystocia incidence is low (1-2%) → uterine inertia accounts for most (like all polyocous species) and other causes include fetal malposition, obstruction of birth canal, deviation of uterus, fetopelvic disproportion and maternal excitement
Lactation peak s at 3-4 weeks postpartum, and poor lactation is a significant cause of improper productivity of pigs (postpartum dysgalactia syndrome)
Provide piglets with needed warmthObservation of nursing activityPrevent crushing and cannibalism
Other management techniques Cross-fosteringSplit-sucklingWell-designed farrowing crates and pensPre-partum vaccination of sowsAppropriate feeding program for lactating sowsCleanliness
24 + 162. Reproductive management in sheep (in large scale herds) (M - 1495)General
Influenced by both genetic and non-genetic factors: Genetic = rapid improvement can be achieved by crossbreeding, provided
that the crosses are appropriate for the local conditions (mainly advantageous under intensive or semi-intensive conditions in which multiple birth are advantage)
Non-genetic = nutrition, presence of phytoestrogens, disease, management techniques, male infertility and environmental factors such as weather
Reproductive efficiency is measured by weaning % (number of lambs surviving to weaning divided by number of ewes mated and multiplied by 100) → acceptable figures depend on the type of operation => weaning % range from 80-85% under range condition with minimal shelter
=> -“- 170-200% under intensive confinement systemFertility can be improved by improved nutrition, ram effect, improved preparation of rams before
joining, reduction in effect of phytoestrogens (resulting from resistance of ewes) and pasture management
The cycle is influenced mainly by the photoperiodism, but also by geographic location, environmental temp. and breed of sheep
Generally, the ewe’s reproductive performance are maximal at 4-5 years of ageThe optimal time to mate ewe’s (naturally or artificially) is in the first half of the estrus period or
12 – 18 hours after the onset of estrus → heat detection requires the presence of a ram, because ewes show no overt signs of estrus
Puberty age varies greatly and is influenced by breed, nutrition and season of birth → well grown lambs (mainly meat breeds) can be mated at 7-8 month of age and 41-45 kg body weight → it is desirable because ewes that cycle as lambs tend to have higher twinning rates as adults and ewes that breed as lambs are able to produce more lambs than those bred at 2 years old
The ovulation rate (major determinant of fertility) is influenced by: Breed = Finn-sheep consistently have multiple ovulation’s, while Marino ewes have lower rateGenetic factors = poly-genic traitAgeNutrition = rate is higher in heavier ewes
= nutritional supplements over a few weeks before mating (flashing) may increase ovulation rate, and flashing with protein-rich supplement is effective in ewes on protein-deficient pasture
= phyto-estrogens cause infertility (reduced twin ovulation, reduced transport of ova through the oviduct and reduced transport of sperm through the cervix → the basis is failure of fertilization resulting from failure of sperm transport through the cervix, reflecting estrogen-induced transdifferentiation of the cervix → the cervix histology resembles the uterus and the structure of the cervical mucus is altered): Temporary ewe graze on estrogenic-pastures around mating time
Permanent → prolonged exposure to phyto-estrogensSeason = in all breeds higher in the fall
Estrus induction Ram effect = introduction of rams or teasers (vasectomized or epididymectomized rams or
testosterone-treated wethers = male sheep castrated at an early age before secondary sex characters have developed) to ewes isolated from rams, and their odor can induce the onset of ovarian cyclicity → the response depends on the depth of an-estrus of the ewe (affected by breed, season, nutritional status, age and postpartum status) → responding ewe commonly ovulate within 48 hours of rams introduction but do-not display estrus → ovulation is followed by formation of a normal or short-lived (5-6 days) corpus luteum → corpus luteum regression and most ewe display estrus (19 days after ram introduction) → ewe ovulate without displaying estrus and commonly form normal corpus luteum → regression of this corpus luteum results in estrus (25 days after ram introduction)
= pre-treatment of ewes with progesterone for a long period (for 7 days) before ram introduction results in estrus accompanying the 1st ovulation (ovulation rate is higher at this estrusthan at subsequent ones)
Pre-treatment with progestagens (for 7-14 days) → followed by Eq chorionic gonadotropin (eCG = 600-750 IU)** fertility if influenced by breed, season, lactation, postpartum period, dry or suckling, nutritional
status natural mating or artificial insemination and number of inseminations (1 or 2)
Estrus synchronization Can be performed in ewes undergoing estrus cycles by using progestagen-containing pessaries (medicated vaginal suppository) or by inj. of PGF2 or its analogs (fertility is better using pessaries than using PG, and may be further improved by using eCG at the time of pessary removal):
a. progestagen-containing pessaries are inserted for 12-15 days → at removal, 400 IU of eCG can be administered → estrus usually occurs on 2-3 days after removal
b. PGF2 administration 10-14 days apart estrus in most ewe within 2-3 days of 2nd inj.
Prenatal loses Embryo mortality = death of embryo up to the end of implantation (day 40 in sheep) → it is the
main source of loss during pregnancy (death during the fetal period are usually few)Because most of the death occur sufficiently early in the pregnancy to allow at least one more
service before the rams are removed, embryo mortality does not usually cause a dramatic fall in lambing % → however, it delays lambing, increase its time distribution, reduces twinning rates, or leave a few ewes barren (infertile)
Embryo death before day 12 does not disturb the normal cycle length, whereas death after this time increases cycle length
The basal level of embryonic mortality (that occurring in the absence of recognized stress) has been estimated to be 20-30% → the causes of this loss are unknown, although environmental factors (as severe under-nutrition, marked increase in nutrition, Se deficiency and high temp.) may increase embryonic loss above this basal level (ureaplasmosis may also contribute to embryonic death)
Fetal death → results most commonly from infectious process almost always in middle and late pregnancy
Pregnancy determination Accurate determination may increase the efficiency of sheep operations by allowing the
separation of pregnant ewes for supplementary feed, lambing supervision and culling non-pregnant ewes
Detection failure to return to estrus (non-marking by ram or teaser)Measurement of plasma progesterone concentrations 18 days after mating (0 = non-pregnant,
pregnant = detection of any level)Laparoscopy = (from 30 days) an endoscope for examining the peritoneal cavityAbdominal palpation = from 100 daysRecto-abdominal palpation = (from 70 days) insertion of a probe into the rectum and palpation of
the abdomen while the probe passes in the uterus from side to side→ in skilled hands, it is fast, accurate and fairly safe (may rupture the rectal wall and cause peritonitis)
Ultrasound pulse echo detection (from 70 days, false positive diagnosis are due to detection of the bladder) = placing the ultrasound transducer anterior and lateral to the mammary gland in the wool-less area of the right flank and directing the beam foreword and upward toward the last rib
Real-time ultrasound scanning = (from 40 days) more expensive but can detect the number of fetuses
Artificial insemination The optimal time for insemination with non-frozen semen is 12-18 hours after the onset of estrusWhen estrus has been synchronized or induced using progestagens and gonadotrophins and/or ram
effect, most ewe are in estrus within 36-48 hours and ovulate at 60 hours → insemination should be done 48-58 hours after pessary removal for cervical insemination, or 60-66 hours for intrauterine insemination with frozen thawed semen
Embryo transfer Involves super-ovulation, embryo recovery, short-term in vitro (out of body) culture
cryopreservation (maintenance of viability by storing at low temp.) and manipulation and transfer of embryo
25. Stimulation of the sexual functions by means of biological and non-specific methods in cow, sheep and pigs (R&O – 37, M – 1462, 1485, 1495)
Light = onset of cyclic activity in mare, ewe, goat and cat depend on changes in hours of daylight:Mare + Queen → stimulated to activity by prolonging photoperiodEwe + Goat → stimulated to activity by decreasing photoperiod
mare = Stabled at the end of December and subject to artificial light, preferably of increasing length → Enable to advance the onset of normal cyclic activity so that there is estrus and ovulation
= Both tungsten (better) and fluorescent lights have been used 200 watt bulb in each loose box, which increases in duration of lighting by 25-30 minutes each week → Reproductive activity will initiate when mare receives 15-16 hours of light each day
ewe = The cycle is influenced mainly by the photoperiodism (but also by geographic location, environmental temp. and breed of sheep)
= Controlled lighting → Enable to change the breeding season from autumn and winter to spring and summer
= Light regimen which does not change in duration → Enable to ensure breeding throughout the year (resemble equatorial climate)
sow = affect puberty only
Male effect – sheep = introduction of rams or teasers (vasectomized or epididymectomized rams or testosterone-treated wethers = male sheep castrated at an early age before secondary sex characters have developed) to ewes isolated from rams, and their odor can induce the onset of ovarian cyclicity → the response depends on the depth of an-estrus of the ewe (affected by breed, season, nutritional status, age and postpartum status) → responding ewe commonly ovulate within 48 hours of rams introduction but do-not display estrus→ ovulation is followed by formation of a normal or short-lived (5-6 days) corpus luteum → corpus luteum regression and most ewe display estrus (19 days after ram introduction) → ewe ovulate without displaying estrus and commonly form normal corpus luteum → regression of this corpus luteum results in estrus (25 days after ram introduction)
sow = “boar effect” is the most influencing management factor= strongest when ♀ are exposed to sight, sound, touch and smell of a mature boar
(direct contact decreases as the number of senses stimulated by the boar decreases) → exposure of peri-puberal gilts (5-8 month) to a mature boar for min. 10-15 minutes provides an adequate stimulus
Weaning of piglets (gilt/sow) = early weaning (as early as 10 days pot-partum) can result in post- weaning an-estrus → to minimize this effect, it is recommended to :
a. wean primiparous sows not less than 14 days into lactationb. wean sow in 2nd lactation not less than 12 days -“-c. wean sow in 3rd or more lactation not less than 9 days -“-
Stress (gilt/sow) = changes of environment (forming new groups by mixing gilts from different pens, housing confinement to outside pens and vice versa) or transport → can stimulate the onset of postpartum estrus
Nutrition = the effect in seasonally breeding species is not clear mare = Stabling and provision of good feeding → Assists in stimulating the onset of cycle
activity in early spring= Yarded mares are turned out to fresh spring grass → 80% come into estrus and
ovulate within 14 days
= Barren (infertile) and maiden (of breeding age but not yet mated) mare maintained in yards on adequate but mainly dried feed-stuffs during the winter and spring → Remain in an-estrus longer than those which are kept out on grass (may be due to larger content of –carotene in fresh grass = precursor for vit. A except in cat essential for proper growth and maintenance of surface epithelium, bones and light sensitive pigments in the eye)
sheep = improved nutrition (flashing) by increasing the dietary intake (mainly energy) before the ewes are mated → may increase the number of follicles which mature and ovulate → increase the number of born lambs
= flashing with protein-rich supplement is effective in ewes on protein-deficient pasture
= there is no evidence that adequate feeding can advance the onset of breeding season
= ovulation rate is higher in heavier ewes= phyto-estrogens cause infertility (reduced twin ovulation, reduced transport of
ova through the oviduct and reduced transport of sperm through the cervix → the basis is failure of fertilization resulting from failure of sperm transport through the cervix, reflecting estrogen-induced transdifferentiation of the cervix the cervix histology resembles the uterus and the structure of the cervical mucus is altered):
Temporary → ewe graze on estrogenic-pastures around mating timePermanent → prolonged exposure to phyto-estrogens
Sow = “flashing” technique to increase the litter size is similar to ewe → it is generally assumed that flashing gilts/sows 4-6 (10 in Merck) days before estrus increases the ovulation rate
= pre-puberal gilts are usually fed a grower-finisher ration ad-libitum until they reach 90-110 Kg or are 5-6 month old separated from growing pigs, placed in gilt-pool pens and limit- fed a balanced ration containing 12-16% protein
= the primiparous (a ♀ which had one parturition) sow mast support her own growth as well as maintenance and lactation demands while her feed intake capacity is not yet fully developed → this problem can be avoid by breeding only gilts in good condition, not-overfeeding during the first gestation, encouraging energy intake during the first lactation (ad libitum feeding, high- energy diets, wet feed and avoiding high temp. in the farrowing room)
cattle = the limiting nutrient in relating to reproduction in beef is energy (not so important in dairy since most are fed rations that supply adequate energy during lactation) =
a. energy levels before calving influences when the cow returns to estrusb. energy levels after calving influences the conception rate
= feed requirement vary during the reproductive cycle => see question 22
26. Stimulation of the sexual functions by means of hormonal methods (R&O – 38)177. Hormonal control of reproductive performance in dairy herdsThe hormonal methods can be divided to various groups:1. Preparations which stimulate the release of anterior pituitary hormones
Ovarian steroid hormones (mainly estrogens) → positive feedback on the anterior pituitary and hypothalamus
Naturally occurring and synthetic estrogens were used to stimulate estrus → direct effect in stimulating estrus behavior and changes in genital tract, but they may also stimulate the release of pituitary gonadotrophins
GnRH → used to stimulate the release of endogenous gonadotrophins → gilts = was used to induce premature puberty, following eCG administration→ cow = wasn’t successful in controlling the time of ovulation, although it can be used to
stimulate the onset of estrus in postpartum cow→ mare = wasn’t proved to be effective in inducing estrus during the seasonal an-estrus
2. Preparations which replace or supplement anterior pituitary gonadotrophinsIt is possible to extract purified FSH and LH from pituitary glands obtained at abattoirs → but it is
too expensive and time consuming for obtaining commercial quantities and there is a danger of transmitting diseases (as BSE)
eCG → (equine chorionic gonadotrophin) obtained from the serum of pregnant mares → mainly FSH-like, but with some LH-like activity
hCH → (human chorionic gonadotrophin) obtained from the urine of pregnant women → mainly LH-like, but with some FSH-like activity
hMG → (human menopausal gonadotrophin) obtained from the urine of menopausal women → high FSH-like action → used to super-ovulate cows for embryo transfer
eCG + hCG → eCG was used to initiate puberty in most domestic species and both have been successfully used to manipulate cyclic activity
Mare = eCG does not appear to stimulate ovarian activity in mares in winter an-estrus (probably due to that the dose required is very large and it is likely that eCG alone is not responsible for stimulating the wave of accessory follicles during early pregnancy)
Cow = eCG administration to an-estrus cow → stimulate follicular growth and ovulation, but the dose response is variable and can frequently result in multiple ovulation’s → thus, it is necessary to withhold insemination at this induced estrus, unfortunately, in many cases the cow will return to the an-estrus state
Ewe = the use of eCG alone to induce estrus in seasonally an-estrus ewes → not successful= progesterone administration before eCG inj. → synchronized ovulation and estrus in
seasonally an-estrus ewes= attempts to stimulate an early return to cyclic activity in lactating ewe → difficult, mainly
in those lactating heavily (presumably owing to the effect of prolactin release)Su = an-estrus gilts and sows → eCG alone or in combination with hCG will promote follicular
growth and estrus → 2nd inj. of hCG 72 hours later will ensure that ovulation occurs= the same technique can be used to synchronize cyclic activity, mainly if used in combination
with a progesterone or other pituitary-blocking substanceBitch = combinations of eCG, hCG and estrogens to induce estrus in an-estrus bitch → usually
induce good behavioral response, but low number which ovulate and subsequently conceive
Queen = mating queen cats with vasectomized tom, stimulating coitus by swabbing the vagina or administration of hCG → induce ovulation → pseudo-pregnancy→ queen may not show return to estrus for 4-8 weeks
3. OestrogensSynthetic or naturally occurring → used to induce estrus in an-estrus animals → in most cases they have a direct effect on the tubular genital tract and on behavior, but it is doubtful if they initiate ovarian activity and ovulation (in fact, large doses could result in pituitary inhibition)
4. ProgestogensProgesterone and pro-gestational compounds → used extensively in most domestic species to
control the estrus cycle, mainly synchronization within groups of femaleGenerally, the exogenous progestagens act in the same way as a corpus luteum → resulting in a
negative-feedback effect on the anterior pituitary and suppression of the cyclic activity initiated by the release of gonadotrophins → when the source of progestogen is withdrawn (or its effect declines) there is a return to cyclic activity
Mare Prevent race + jumping horses from coming into estrus at an unwanted time
inj. 0.3 mg/kg BW/day
Return to normal fertile activity 3-7 days after treatment ceases
Stimulate onset of cyclic activity
0.044 mg/kg BW mixed in feed (in vegetable oil) for 10 days and then stopped
Good response when given in late transitional phase from un-estrus to cyclic activity, when follicles are present (better results if increased day-light is used)
Suppress estrus (for shows or other functions)
0.044 mg/kg BW – in feed for 15 days
Suppress estrus in mare with prolonged estrus or other aberrant (deviated) sexual behaviorControl the time of estrus so that effective use can be made of a stallion
Fed for 15 days and then stopped
Come into estrus 2-3 days after treatment ceases
Cow = general use = suppress estrus (as in mare) or Synchronization for AI or to overcome problems of estrus detection → treatment for 18-21 days
Synthetic substances (Norgestamet) for 18-21 days
Contain 3 mg progesterone→ on insertion, 3 mg Norgestamet + 5 mg estradiol are inj. IM as a 2 ml dose
Come into estrus 4-6 days after treatment ceases, but the fertility in the 1st estrus is lower than normal (may be due to impaired sperm transport as a result of the atypical hormone balance)
Norgestamet and PRID contain (below) also oestradiol → used as anti-luteotrophic and luteolytic agent
Subcutane implant of synthetic progestogens + inj. of oestradiol (at the same time)
Implant removed 48-60 hour later→ followed by a double fixed-time AI (48 and 60 hours later) → good synchronization and fertility (65% conception rate) and the main disadvantage is the need to handle the cow a 2nd time to remove the implant
Stainless steel coil covered with an inert elastomer, placed in the vagina (using a special speculum) → better when inserted on day 13-14 of cycle (and not days 2-4)
Contain 1.55 g progesterone→ absorbed and produce concentration (in peripheral blood) comparable with max. levels of di-estrus → removed after 12 days and the cow comes into estrus within 2-3 days → good conception rate following a double fixed-time AI (57 + 74 hours after removal)
Controlled internal drug release device (CIDR-type B)
T-shaped device containing 1.9 g progesterone → function like the PRID
**By using PGF2, at the time of removal of the implant (subcutane, CIDR or PRID), synchronization approaches 100% → better results are achieved if the PGF2 is inj. 24 hours before removal
Ewe = general use = induce estrus in an-estrus during the non-breeding season and synchronizat. of ewe already showing cyclic activity
= most pro-gestational substances are administered via the intra-vaginal route in the form of impregnated sponges or tampons → we can use progesterone or its analogs, mainly fluorogestone-acetate (FGA) and medroxyprogesterone-acetate (MAP)
= the progestogen is absorbed from the sponge in a sufficient rate to ensure a full negative feedback effect on the pituitary function
= when intra-vaginal sponges are used outside the normal breeding season, it is necessary to use eCG as a source of gonadotrophin at the end of the progesterone priming period
= the onset of normal cyclic activity can be determined by running vasectomized rams with a harness or by using the rule-of-thumb calculation (from the lambing records of the non- synchronized flock, calculate the date when 50% of the ewe had lambed → than, if the sponges are not to be inserted earlier than 150 days before the same date for the current year, eCG will-not be required) to determine if eCG is necessary
= the eCG dose should stimulate estrus and ovulation without causing super-ovulation → opinion vary on the doses needed and the time of inj. → 48 hours before sponge removal (the advantage is so small that the additional handling of the ewe does-not make it cost-effective)
= fertility may be reduced if ewe are mated at the 1st synchronized estrus (may be due to poor absorption of the progestogen from the sponge or to an effect of the abnormal steroid balance on sperm transport and survival) → so, if the ewe fails to conceive at the 1st estrus, there is usually good synchrony and conception rates at the 2nd
= attempts to induce estrus in the early post-partum and lactating ewe have been un-successful (may be due to the influence of prolactin)
Goat = similar to sheep (sponges in conjugation with eCG) → initiate estrus during the normal period of an-estrus (goat show intense estrus 36-48 hours after sponge removal)
= eCG doses = July 500-600 IUAugust 500-400 IUSeptember 300-0 IUOctober onwards eCG is not required
= goats object to the insertion of the sponges (mainly the applicator) much more than ewe, and in median goats it is better to use a finger and lubricant
Sow altrenogest/allyltrenbolone (both sold in oily solution)
15-20 mg/day in food for 18 days
Suppresses follicular maturation → no apparent effect on the life span of the corpus luteum → good synchronization of estrus 5-7 days after withdrawal (breed differences in the degree of synchronization → good farrowing rate in cross-breeds)
Lower doses (2.5-5 mg/day in food)
Follicular growth is not inhibited and cystic follicles developed within 10 days after the beginning of treatment (similar problem have been encountered with other progestogens)
Postpone estrus in bitch when administered during an-estrus → can be maintained for over a year by inj. progestogens at intervals of 3-5 months or after a 40-day course of oral administration of tbl. twice a weekPrevent estrus from occurring at the first signs of pro-estrus → a single inj. or oral administration at a higher dose rate than for postponement, but for shorter duration
** administration of progestogens at the time interval before the onset of the next estrus, is rather un-predictable if treatment is not continued → furthermore, there is good evidence that continued and frequent use of such preparations can predispose to reproductive disorders, particularly cystic glandular hyperplasia of the endometrium
Queen = suppression of estrus is desirable mainly for planing of litters throughout the year and to allow the queen a period of rest from sexual activity after a litter and regain condition before being breed again
= if a queen is allowed to call repeatedly without mating this may lead to considerable loss in condition due to relative inappetance during estrus (mainly in oriental breeds, which have short inter-estrus intervals and long periods of estrus)
= Proligesterone + Medroxyprogesterone-acetate (inj. progestogens)→ suppress estrus for up to 7 months or more following a single inj. and can be repeated every 5 months to achieve permanent estrus suppression (loss of pigmentation in the area overlaying injection site is occasionally encountered)
= Megoestrol-acetate (oral progestogens) → administration of 5 mg as soon as signs of estrus are observed, can prevent an individual estrus period (this method is less suitable in cats than in dogs because of the very rapid and sudden onset of estrus behavior)
= Megoestrol-acetate (oral progestogens) → administration of 2.5 mg daily or weekly (depending on whether treatment was started during the breeding season or an-estrus) → estrus postponement
= many queens treated with progestogens will show behavioral changes, mainly lethargy and weight gain, and some queens may also develop endometritis or diabetes mellitus
5. Prostaglandin’sSince the length of the inter-estrus interval in most species is controlled by the duration of the
lifespan of the corpus luteum, premature lysis, induced by administration of PGF2 or its analogs, can be used to manipulate the normal pattern of cyclic activity
Since prostaglandin’s are abortifacient, they mast not be used in animals that might be pregnant → pregnancy diagnosis if there is any doubt
The corpus luteum of mare, cow, ewe, goat and sow normally responds to the adminis. of exogenous PG, but in bitch and queen, it is generally un-responsive – unless subject to repeated doses
In mare, cow, ewe, goat and sow it is important to examine when the corpus luteum is responsive or non-responsive (refractory in the beginning of estrus or already regressed under the influence of its own endogenous auto-lysis) to exogenous prostaglandin → see Fig. 1.41
Mare = PGF2 or its synthetic analogue cloprostenol → the onset of estrus is generally well synchronized (3 days after treatment), but the subsequent ovulation has a time spread of 7-12 days → improved by inj. of hCG or GnRH on the 2nd-3rd day of the induced estrus
= mare synchronization is useful mainly if the mare or stallion has to travel a distance for service, it eliminates the need for frequent teasing of mare and also if the heat was missed (especially foal heat) since it enables estrus to be induced prematurely and avoids the need to wait for the next spontaneous heat
Cow = PG are used to synchronize estrus in groups of beef (cow and heifers) and dairy (heifers) where detection of estrus is difficult → allow routine use of AI at a predictable time (allows the use of semen from genetically superior sire improved genetic potential of offspring’s)
= 2 inj. of PGF2 or its synthetic analogues (cloprostenol) – given at 11 days interval (to a group at randomly different stages of cycle) → all animal come into estrus 3-5 days after the 2nd inj., and ovulate at about the same time → conception rates are comparable to those following AI or natural service at a spontaneous estrus – if the cows are inseminated twice at a fixed time (72 + 90 or 96 hours) after the 2nd inj. → see Fig. 1.42
= the efficient of synchronization following the double inj. is usually much better in heifer than in cows → it is not known precisely why, but possible explanation is the long-low progesterone level occurring in up to 15% of cows (presumably the delay in the corpus luteum reaching a sensitive stage → PG concentrations remain low for a prolonged period of time after ovulation interfere with synchronization)
= to reduce costs and to improve pregnancy rates → all animals in the group are injected with PGF2 on the same day → observed for estrus during the following 5 days (cows with a sensitive corpus luteum at the time of the 1st inj. will have an induced estrus 3-5 days later) → cow in estrus is inseminated as normal, and those not identified receive the 2nd inj., followed by fixed time AI → any individual showing estrus signs a few days after fixed- time AI should be re-inseminated
Ewe = PGF2 or analogue given to ewe with a sensitive corpus luteum → estrus occur 36-46 hours after injection
= to synchronize a group at different stages of estrus → necessary to give two inj. 8-9 days apart
= conception rates following natural mating are comparable with un-synchronized ewesSow = prostaglandin’s and their analogues are not luteolytic in sow until the 11th–12th day of the
estrus cycle → thus, it is not possible to devise a regimen of inj. that will synchronize a group of animals with randomly distributed cyclic activity
= it is possible to prolong the lifespan of the corpus luteum with inj. of estrogens on days 10-14 of the cycle → prostaglandin’s can be inj. after 5-20 days → induce estrus 4-6 days later
= inj. of eCG or hCG at any stage of the cycle → produce accessory corpus luteum → inj. of prostaglandin’s → luteolysis
Bitch & Queen = prostaglandin’s do-not cause luteolysis
6. MelatoninThe pineal gland controls reproductive activity in seasonal breeding species (as mare, sheep, goat
and cat) by secretion of melatonin as the daylight hours reduceMare = it has not been used successfully to modify seasonal activity because it would be
necessary to inhibit the secretion of melatonin or neutralize its effect to advance the time of onset
Ewe & goat = (long day breeders) implant containing 18 mg melatonin (inserted subcutaneously at the base of ear) → advance onset of breeding season by 2-3 month with good fertility
= it is critical that male are sufficiently separated from female (out of sight, sound and smell) for at least 7 days before the insertion of the implant → must remain separated for at least 30 days, but not more than 40 days → male re-introduced→ peak mating activity occurs 25-35 days later
= melatonin should not be used in ewe lambs
7. Immunization proceduresConjugation of a derivative of the natural ovarian hormone androstenedione with human serum
albumen → injected to Ewe twice (8 and 4 weeks before mating) and stimulate the production of antibodies to androstenedione → binds free, naturally occurring androstenedione in the blood → increased ovulation rate and number of lambs born by about 25% (the precise mode of action is not fully understood)
Injected to Ewe twice → 8 and 4 weeks before mating (if the ewe was treated in the previous season, one inj. only is required 4 weeks before mating)
Mountain and hill ewe breeds should-not be treated because of the danger of pregnancy toxemia (only ewe which are likely to be adequately feed during pregnancy should be treated)
27. The significance of the super-ovulation in the breed of domestic animals (R&O – 680)
Gonadotrophins → induce multiple ovulations in the ovaries of donor cow (super-ovulation) → single embryos can be recovered and transferred to other cows 6-8 days after service at natural estrus
Ovarian response to super-ovulation treatment is very variable both between animals and between treatments of the same animal
The donor cow can be super-ovulated repeatedly at about 6-8 weeks intervals with no adverse effect on subsequent fertility
Fertilization failure can be due to:a. the substantial luteinizing activity of eCG and FSH preparations can cause premature
ovulation abnormalities of oocyte maturation and asynchrony between maturation of the oocyte and the follicle effect the viability of some ovulated oocytes
b. deficient sperm transport in super-ovulated animals reduced number of sperm in the uterine tube at the time of fertilization
Gonadotrophin treatment is initiated on days 9-14 (estrus = day 0) of a normal estrus cycle Several gonadotrophin have been used to super-ovulate cattle:
eCG Single inj. of 2500-3500 IU has longer half-life in the cow than FSH or hMG require only 1 treatment, but its effect persists even after induced estrus and in some cows embryo transfer is adversely affected poorer recovery rate of embryos
Equine FSH Multiple inj. of 20-24 mgPorcine FSH Multiple inj. of 40-50 mg
2/day for 4-5 daysOvine FSHhMG
↓Prostaglandin is administered 48-72 hours later cause regression of the mid-cycle CL and induce
estrus (usually 40-56 hours later)↓
Normal manifestation of estrus donor is usually inseminated twice (12-18 hours apart) [the super-ovulated donor appear to be sensitive indicator of the fertility of semen only bulls with
high fertility should be used]↓
A modified phosphate-buffered saline (PBS) is used both for flushing the uterus and for storage↓
Settling and aspiration or filtering (through a plankton filter) of the flushing medium↓
Embryos are located with a stereoscopic microscope↓
Embryos can be: 1. kept in PBS on the bench for at least 8 hours with no loss of viability2. cultured for up to 48 hours with acceptable results on transfer3. cooled to +4C and maintain and maintained in a state of suspended development
for up to 3 days 4. stored for long periods by freezing
28. Morphological and functional changes of the corpus luteum during the estrus cycle in the cow (R&O – 19)Usually 1 follicle ovulates and 1 ovum is liberated after each estrus (twin ovulation in 4-5% of cows)In dairy Bo 60% of ovulations are from the right ovary (in beef Bo the difference is not so great)The ovulatory follicle is selected 3 days before ovulation = follicles grow under the influence
of FSH → one follicle obtain dominance and subsequently ovulate (un-known intra-ovarian mechanism which does-not involve FSH suppression)
During pro-estrus and estrus the selected follicle enlarges and ovulates (ruptures) Ovulation usually occurs in an a-vascular area of the follicular wall so hemorrhage is not a feature of
Bo ovulation (although there is marked post-ovulatory congestion around the rupture point and some- times a small blood clot is present in the center of the new CL – as seen in PM examination)
On rupture, the ovum (+ most of the follicle fluid) is expelled through a small opening in the follicle → follicle collapses (can be detected in rectal palpation)
The CL develops by hypertrophy and luteinization of the granulosa cells lining the follicle → enlargement is rapid, and 48 hours after ovulation it attained 14 mm → at this stage, the CL is soft, dull cream color and the luteinizing cells can be seen in the form of loose pleats
By 7th-8th day of di-estrus the CL attains its max. size (20-25 mm ), the luteinized pleats are relatively complete, the body comprises a more or less homogenous mass, it is yellow to orange in color and its shape varies (most are oval, but some are irregular)
Some times the center of the CL is occupied by a cavity (4 mm on average – usually smaller but occasionally up to 10 mm or more), filled with yellow fluid → in this case, a pin-head depression in the center of the projection from the ovarian surface is the evidence of ovulation (serves to differentiate them from luteinization of the walls of the follicle without ovulation = ovarian abnormality)→ in the past, this cavity was described as cystic-CL, but Noakes says it is normal
The CL maintain its max. size and appearance – until the onset of pro-estrus (24 hours before onset of heat) → from this point it undergoes rapid reduction in size, changes in color and appearance
By the middle of estrus, it reduces to 15 mm (its protrusion is much smaller and less distinct), its color changes to bright yellow, its consistency becomes dense (invasion of scar tissue)
By the 2nd day of di-estrus, it reduces to 10 mm, its outlines become irregular and its color changes to brown
By the middle of di-estrus, it shrinks to 5 mm and its surface protrusion is a little larger than a pin-head → as it gets older – its color changes to red or scarlet → small red reminders of CL persist for several month
29. Fertilization and implantation (R&O-51,P –586, 588, 589(t), 590)Fertilization = Conception = the male and female gametes unite and form a zygoteImplantation = the attachment and embedding of the fertilized ovum in the endometrium
= before implantation, the embryo nutrition is provided by the zygotes own cytoplasmic reserves and by the uterine milk = uterine secretion that contains proteins (18% in mare, 10% in cow) and lipids (0.006% in mare, 1% in Ru)
= trophoblast = the peripheral cells of the blastocyst, which attach the fertilized ovum to the uterine wall and contribute to the placenta and the membranes that nourish and protect the developing organism → the inner cellular layer is the cyto-trophoblast and the outer layer is the syn-trophoblast
Mating Spermatozoa wait in the ampulla of the uterine tube (oviduct) for the arrival of oocyte (although only 1 sperm is needed, it is estimated that million are needed to create suitable environment for fertilization)
Spermatozoa release proteolytic enzymes from their acrosome→ acrosin in Bitch + Queen, and acid-phosphatase in Mare + Cow + ewe + goat + Sow
Soften and loosens the layers of the cells covering the zona pellucidaOvum pass from the infundibulum to the ampulla, where fertilization (conception) occur → it lasts 6-24 hours (depend on the species), during this time the ovum is activated and merges its cytoplasm with that of the spermatozoa (the spermatozoa shades its tail and mid-piece after it passes the plasma membrane and before the fusion)In the ampulla, fertilization is a multi-step process:a. Physical penetration of the zona pellucida of the oocyte by a single spermatozoab. As it reaches the cytoplasm of the egg, the spermatozoa causes the regression of micro-granules
bordering the endoplasmic surface of the plasma membrane of the oocyte and at the same time, receptors on the zona pellucida are changed and become un-responsive to other spermatozoa (prevents poly-spermy which is the fusion of more than one sperm with a single ovum)
Zygote which starts to cleave (divide) = about once a day during its passage towards the uterus (by
peristaltic contractions and ciliary movement in the uterine tube)The variable duration of travel by the fertilized egg in the oviduct is determined positively by the
degree of activity of the tube muscle and cilia, and negatively by the muscle contraction of the tube-isthmus or utero-tube junction (both positive and negative factors are probably influenced by variable concentration of ovarian steroids and possibly by local production of prostglandins)
Arrival on day… Number of cellsMare 5-6 Blastocyst Cow 3-4 16-32Ewe 3 8Sow 2 4-8Dog 5-8 16-32Cat 5-6 8
**un-fertilized egg of Mare, remain in the tubes for several month, where they slowly degenerate
Further division and orientation and the morula (in the uterus), which becomes a hollow structure (blastocyst)Up to the time of shading of the zona pellucida (at the 9th day), there is only little absolute growth of
the egg from its original dimension (1.4 mm)From the time of its arrival to the uterus until attachment, the zygote is propelled or aspirated in the
uterine lumen, where it is nourished by the uterine milkIn polytocous species (giving birth to several offspring’s in one pregnancy), there is free migration of
embryos between the cornua, regardless the side of ovulation (the blastocysts are arranged throughout the uterus so as to utilize effectively the uterine space)
In monotocous species: cow such migration hardly ever occurs; ewe occurs occasionallyAfter the 9th day the blastocyst enlarges rapidly, and the embryonic attachment (implantation)
occurs at the following times :Mare 25-30 daysCow 12 daysEwe 15 daysSow 14 daysDog + Cat 13-17 days
It connects between the trophoblasts (the peripheral cells of the blastocyst) and the uterine wall (endometrial epithelium)
It is a gradual process, that is completed in 1 week in Bitch and Queen 2 weeks in Small Ru and Sow 4 weeks in Mare and Cow
The placenta can be classified according the degree of proximity of the maternal and fetal blood circulation and distribution of villi (see question number 31)
Degree of proximity Villi distributionMare + Sow
Epithelio-chorial placenta (simplest placenta)
Diffuse placenta Villi are uniformly dispersedThe chorion is everywhere in contact with the
endometriumRuminant Cotyledonary
placentaVilli are grouped into multiple circumscribed
areasPlacentome (cotyledon + caruncle)
Carnivore Zonary placenta Villi are disposed in the form of a wide encircling belt
Further invasion of the endometrium by trophoblast which is now apposed to the maternal capillaries (placenta is partially haemo-chorial because the main zonary placenta is flanked by marginal hematoma– in which accumulation of maternal blood between the uterine epithelium and the chorion, directly bathes the chorionic villi that project into it)
Primates Only the tissue of the chorionic villi separate the fetal and maternal blood
30. Placental development and placental function (R&O – 52)Placental developmentThe allantois spread-out into the chorionic vesicle and makes contact with the chorion fuses outside with the chorion (vascular allanto-chorion), and inside it fuses with the amnion (allanto-amnion) the allanto-chorion eventually surrounds the allanto-amnionWhen the vascularization of the chorion by the allantois is complete (40-60 days in cow), it is ready
to participate in placental function (prior to this the embryo has been nourished through its chorion and amnion by diffusion from the uterine milk)
In Ru, the allanto-chorion contacts the uterine caruncles, finger-like processes (containing capillary tufts) grow out from the allanto-chorion into the crypts of the maternal caruncles (also surrounded by capillary plexuses) → ruminant cotyledon (or placentome) through which takes place nutrient + gas exchange between the mother and fetus (on average there are 120 functional cotyledons in cow and 80 in sheep there can also be numerous functional cotyledons in the non-pregnant horn, since the chorion and allantois extend into the non-gravid horn)
Other species do-not have cotyledons and the villi are dispersed over the placental areaDuring early development of Ru embryo occurs fusion between the allanto-amnion and allanto-
chorion → thus, where it lies over the amnion, the allantois is reduced to a narrow channel → its shape resembles the letter “T”, with the stem coming out of the urachus, along the umbilical cord and then diverging as the 2 cross-pieces over the lateral face of the amnion → consequently, there is little allantoic fluid over the amnionic area (most of the fluid lies in the extremities of allantois, which lies partially in the non-gravid horn )
A similar fusion takes place in pig (between the amnion and allantois) In late gestation in Bo uterus, with the increasing pressure of accumulating amnionic fluid, the allanto-chorion tends to separate again from the allanto-amnion, so that the allantois may almost surround the amnion → thus, the final arrangement of the 2 fetal sacs closely resemble that of the horse (the amnion floats almost freely in the allantoic fluid)
In horse, the amnion, except for its attachment at the umbilicus, floats freely in the allantoic fluid throughout gestation
In carnivores, as in the domestic herbivores, the allantois also grows out into the chorion, but only the central part of it becomes vascularized and serves as a placenta
The amnion is surrounded by allantoic fluid, as in the horse
Placental function Transport of nutrients from the mother to the fetusTransport of excretory products from the fetus to the motherGas exchange between the mother and fetus (function as fetal lungs)Hormone exchange between the mother and fetusMechanical protection of the fetusEfficient barrier against the transfer parasites, bacteria and viruses, although some organisms can
pass (the basis for the differences in the “placental barrier” of different species depends on the degree of intimacy between maternal and fetal placental blood vessels)
*** Co2, O2, electrolytes, hormones and water move freely between the maternal and fetal placenta circulation by simple diffusion gradients from high concentration to lower one
*** Amino acids, glucids and minerals active transfer from low concentration to areas of higher one (active transport requires energy)
31. Classification of placenta (R&O – 55)
Classification according to whether or not maternal tissue separated off with the fetal tissue at birth
Desiduate placenta Bitch + QueenNon-desiduate placenta Other species
Classification according to the way the villi are distributed in the fetal chorion
Diffuse placenta Mare + Sow Villi are uniformly dispersed Cotyledonary placenta Ruminant Villi are grouped into multiple circumscribed areasZonary placenta Carnivores Villi are disposed in the form of an encircling belt
Classification according the degree of proximity of the maternal and fetal blood circulation (recognizes the phagocytic property of the trophoblast, or chorionic epithelium, that may be exerted in tissues with which it comes in contact)
Epithelio-chorial placenta (simplest one)
Mare + Sow The chorion is everywhere in contact with the endometrium, and there is no loss of maternal tissue
Syn-epithelial-chorial placenta
Ruminant After embryonic attachment, a syncytiuma is formed on the maternal side of the placentome (cotyledon + caruncle) by fusion of bi-nucleate cells derived from the endometrium and troph-ectodermb → unlike sheep and Goat, the syncytium in Cow is temporary because the syncytial plaques are overgrow by the rapid division of the remaining maternal epithelium
Endothelio-chorial placenta
Carnivores Further invasion of the endometrium by trophoblastc, which is now apposed to the maternal capillaries
This placenta is partially haemo-chorial because the main zonary placenta (endothelio-chorial) is flanked by marginal hematoma (the green border in dog and brown border in cat) – in which accumulation of maternal blood between the uterine epithelium and the chorion, directly bathes the chorionic villi that project into it
During parturition, separation of canine placenta causes the escape of this altered blood from the marginal hematoma → characteristic green color to the normal parturient discharge
Haemo-chorial placenta Primates Only the tissue of the chorionic villi separate the fetal and maternal blood
asyncytium = multi- nucleated cellular mass produced by merging of cellsbtroph-ectoderm = the earliest trophoblastc trophoblast = the peripheral cells of the blastocyst, which attach the fertilized ovum to the
uterine wall and contribute to the placenta and the membranes that nourish and protect the developing organism (the inner cellular layer is the cyto-trophoblast and the outer layer is the syn-trophoblast)
32. Placental hormone production (P – 598)Progesterone and estrogens In most animal (except dog + cat), stimuli from the endometrium and trophoblast stimulate formation
of the CL (CL only function is to secrete progesterone, and it regresses unless the animal conceives)
From fertilization to implantation, ovaries (CL) produce the PG required for maintenance of gestation
Goat, Sow and Bitch the ovaries secrete progesterone throughout pregnancy and are essential for maintenance of gestationSow placental production of progesterone is not enough to maintain gestation after
ovariectomyMare, Cow, Sheep, Cat placenta can supplement/replace the production of progesterone by the CLCow the placenta is able to convert progesterone into estrogens (act with the progesterone to
produce an environment suitable for pregnancy)Mare, Ewe and Sow placenta is un-able to convert progesterone into estrogensMare during the 1st half of pregnancy, the high level of progesterone is provided by the CL of
ovulation and afterwards by secondary luteinized follicles (the ovaries are stimulated to produce a series of accessory ovulations, each followed by a progesterone secreting CL) → during most of the 2nd half of pregnancy, the maternal (CL) progesterone level is low, but the placenta produces metabolites (progestins) of progesterone (5–pregnanes, estrogens) which replace the progesterone (after implantation, the placenta becomes an endocrine organ) → 2 weeks before parturition, occurs a rise in progestins and progesterone
In most species, secretion of estrogens by the placenta begins only after the first 1/5-1/4 of gestationFrom 8th week of gestation, mares placenta produces estrogens excreted in the urineThe excretion of estrogens at ½ and near parturition is a reflection of correspondingly high plasma
concentrations of estrogens Cow, Ewe plasma estrogen remain stable throughout gestation and peak only just before
parturition Goat estrogens increase constantly reach levels comparable with does in Sow and mare s few
days before full term is reached
Pregnant mare serum gonadotropin (PMSG) = equine chorionic gonadotropin (eCG) Secreted by the endometrial cups in the fetal part of the placenta, in high concentrations during the 1st
half of gestation → has mainly FSH activity and stimulate formation of accessory CL in mareIt is a unique glycoprotein molecule, having both FSH and LH activities at a ratio of 10-30:1Used in embryo transfer to produce super-ovulation → a single inj. of PMSG induces follicular
growth and ovulation in domestic animals (except mare, which only respond to equine adenohypophysial extract and to FSH-rich human menopausal gonadotropin - hMG)
Human chorionic gonadotropin (hCG)Primates only → may be detected in urineProduced by the trophoblast very soon after implantation → has luteinizing activity (show mainly
LH activity and maintain CL of pregnancy in primates)
Placental lactogens (PL)Secreted by Cow, Ewe and Goat placenta throughout pregnancy, but not found in the placenta a few
days before parturitionPlays a role in the mammary gland growth in Ewe and Goat (not in Cow) and regulate maternal
nutrients to the fetus
Protein B (R&O – 84)Unknown function → found in all animals (?)
Cow → secreted from the bi-nucleated cells of the trophoblastic ectoderm → found in serum from day 24 after conception → can be used to confirm pregnancy, but since it has long half-life it can also be found in serum many weeks post-partum
33. Placentation in various species of domestic animals (R&O – 58)Mare Much of the allanto-chorion and most of the amnion are contained within the gravid horn with a
direct continuation of similar width into the uterine body → the part of the allanto-chorion which projects into the non-gravid horn is much narrower and is about 2/3 the length of the gravid horn segment (in rare bi-cornual pregnancy the allanto-chorion occupies both cornua to similar extent)
Projecting into the allantoic fluid are invaginations of the allanto-chorion → occur in proximity to the endometrial cups whose secretion accumulates I them (their size corresponds with the secretory activity of the endometrial cups when distended with secretion, they are called allanto-chorionic pouches) → they are few in number (no more than 6) and sometimes absent, disposed in a concentric manner at the base of the pregnant horn, they are present from the 20th week of gestation and produce eCG
The endometrial cups are formed from cells which invade the endometrium from the embryonic trophoblast (they cause reaction in the maternal tissue leads to freedom of the cups at day ) → the cups have immunologic function in protecting the conceptus
The surface of the allanto-chorion adherent to the endometriom is red in color and has “velvety” appearance and texture
The area adjacent to the internal opening of the cervix is devoid of placental villi → giving rise to the so called “star”
The inner surface of the allanto-chorion (outermost when the placenta is shed) has smooth surfaceWeight of fetal fluids (kg):
Gestation month Weight of total fluid (Kg)1 0.03-0.042 0.3-0.53 1.2-34 3-45 5-86 6-107 6-108 6-129 8-1210 10-2011 10-20
Ruminants Throughout the gestation the amnion enclosing the fetus, together with the larger portion of the
allanto-chorion, remains in the uterine horn corresponding to the ovary with the CL (a similar “limb” of allanto-chorion projects across the uterine body into the other horn)
Most of the allantoic fluid gravitates in the poles of the allanto-chorion (lie in the horns) → the uterine distention is the main clinical sign of early pregnancy
By the 3rd month, considerable fluid (up to 0.75 lit.) has accumulated in the amnion → gives rise to the palpated in the pregnant horn
On the inner face of the amnion (mainly near the umbilicus) are numerous raised, rough, round foci (amnionic plaque) → they are rich in glycogen, but their function is un-known → disappear after 6 month of gestation
Towards the end of pregnancy, sooth, rubber-like masses float in the amnionic and occasionally allantoic fluids (hippomans) → comprise of aggregations of fetal hair and meconium around which solts are deposited from the fetal fluids → no functional significance
Cow = the total quantity of fetal fluid increases progressively throughout pregnancy (5 liter at 5 month and 20 liter at the end)
= throughout gestation the allantoic fluid is watery to urine-like= in the first 2/3 of pregnancy the amnionic fluid is similar to the allantoic fluid, but in the last
1/3 it becomes mucoid (gives it lubricant property – which is helpful at parturition)Sheep = the total volume of fetal fluids increases with advancing age of the conceptus:
**when twins are present the fluid volumes are approximately doubled
Sow = The uterine surface of the allanto-chorion has small, round, gray foci (areolae) in which villi are
absent → occur opposite focal aggregations of uterine glandsFetal fluids = allantoic fluid increases from 130 ml (at 1 month) → 200 ml (at the end) →
tendency to decline= amnionic fluid does not increase over 20 ml (in first 2 month) → rises to a max. of 75-
200 ml → wide variation with tendency to decline
Cat = Amnionic rises gradually to 10-15 ml → some decrease → slight rise just before birthAllantoic fluid rises more rapidly → at mid-gestation higher than the amnionic (20 ml)→ declines to
6 ml at the end of gestation
Approximate length of blastogenesis and embryogenesis periods (P – 590)
Embryogenesis = the process of embryo formation (from the time the long axis begins to develop to the time that the major structures begin to develop than it becomes a fetus)
34. Nutritional function of placenta, fetal nutrition and metabolism, course of the circulation, cardiovascular changes
Nutritional function of placenta + Fetal nutrition and metabolism (P – 115, 597)
Before implantation, the embryo nutrition is provided by the zygotes own cytoplasmic reserves and by the uterine milk = uterine secretion that contains proteins (18% in mare, 10% in cow) and lipids (0.006% in mare, 1% in Ru)
After implantation, the embryo nutrition is provided by the placenta:Co2, O2, electrolytes, hormones and water move freely between the maternal and fetal
placenta circulation by simple diffusion gradients from high concentration to lower oneAmino acids, glucids and minerals active transfer from low concentration to areas of higher
one (active transport requires energy)
Course of the circulation + Cardiovascular changesIn the fetus
Foramen ovale = open in the septum of the fetal heart → connects between the atriasDuctus arteriosus = connection of the aorta and pulmonary artery
At birth, the “placental branch” of the fetal circulation is terminated, the umbilical vessels and sinus venosus constrict, and their blood is infused into the neonate → loss of maternal oxygnation causes asphyxia → triggers respiratory gasping and inflation of the lungs → functional closure of the foramen ovale and ductus arteriosus occurs after 1-2 days (permanent closure requires a few weeks)
35. Position of the fetus in the uterus (R&O – 224, P – 611)Presentation = depending whether the head or hind quarters of the fetus appear first in the pelvic inletAbout 99% of foals and 95% of calves are presented anteriorly (higher % of posterior presentation in
excessively large fetuses, and much higher % in twin birth)When sheep → single lambs show similar % of anterior presentation as cow
→ twins show considerable % of posterior presentationSow and bitch (polytocus) deliver 60-70% of fetuses in anterior presentation
In posterior presentation the hind-limbs may be extended or flexed beneath the fetal body:Extended → little more dystocia than with anterior presentationFlexed (breech presentation) → increased incidence of dystocia
Month of gestation PresentationCattle 1st+2nd No evident polarity
3rd Equal numbers of anterior and posterior presentation4th+5th+half 6th Most in posterior presentation (between 5½ and 6½ months the polarity
becomes reversed)End of 6th Frequently equal numbers of anterior and posterior presentationMid 7th Most in anterior presentationBeyond 7th 95% in anterior presentation (the final birth presentation by the end of
the 7th month)The natural forces which bring about these changes in polarity are not understood, but presumably
reflex fetal movements occur in response to changes in the intra uterine pressure due to myo-metrial contractions, movements of adjacent abdominal viscera or to contraction of the abdominal muscles
The higher % of posterior presentation in early gestation is the expected result of suspending an inert body with the same gravity center → as the fetal nervous system develops (and with it the sense of gravity), the fetal calf begins to show a reflex that tends to bring the head up → if this assumptions are true, then posterior presentation should not be regarded as obstetric accident, but a result of a sub-normally developed fetus or uterine deficient tone
Month of gestation PresentationMare Between 6½-8 ½ 98% assume an anterior presentation
Position = orientation of the fetal vertebral column in relation to the maternal vertebral columnThe natural tendency is for the fetus to lie with its dorsum against the greater curvature of the uterus
→Eq = upside down (ventral position) during late gestation during labor the fetus changes
from ventral to dorsalBo = upright (dorsal position) during late gestation maintain this relationship during birth
Posture = the disposition (flexion or tension) of the fetal head, neck and extremities in relation to the body of the fetus
Normally, the head and fore-legs are extend in front of the fetus, and the hind-legs are stretched behind
Bo in the last 2 month of gestation → anterior presentation and dorsal position with flexion of all the appendages joints
Eq → ventral position with flexion of all the appendages jointsThis disposition to flexion of appendages achieves the maximum economy of space → during
parturition (un-known mechanism), the hind-limbs become extended back and the fore-limb become straightened in front of the fetus (the posture of the fore-limbs is necessary for normal birth in cattle)
In polytocous species → normally, anterior presentation, dorsal position and extended posture (feto-maternal relationship is not so exact → position of the comparatively small fetal limbs is less important than in Eq or Bo, unless there is abnormally low number of over-sized fetuses – where malposture of the limbs may cause dystocia)
36. Fetal growth rate, estimation of age (R&O – 61, 78)
See also pregnancy diagnosis in questions 42-46Long bones length (conveniently radius and tibia) is a reliable indicator of fetal age from 50 days of
gestation to its end in sheep
Day after conception Length of radius Length of tibia50 4.8 560 10 1270 16 1985 25 32100 36 47110 47 63120 56 76130 67 91140 74 100150 79 107
Calculation of the age of fetus (X) from crown-anus length (Y):
Calf X = 2.5 (Y + 21)Lamb X = 2.1 (Y + 17)Pig X = 3 (Y + 21)
X = developmental age in daysY = crown-anus length in cm
Fetal body length in cow at various stages of pregnancy:
37. Morphological and functional changes in the organism of the dam during gestationChanges in genital organs Mare (R&O – 67)
Up to 40 day of gestationOvaries The CL can only be palpated (per rectum) for 2-3 days after its formation (therefore,
although it persists for 5-6 months, it can-not be identified)Except in vary large mare, the ovaries can be palpated throughout pregnancy
Uterus During late di-estrus and estrus the uterine is soft and the endometriun thin after ovulation, tone and the uterus becomes more tubular (not marked in non-pregnant animal and these changes reduce after CL regression at days 10-14) CL persists and the tone reaches max. at 19-21 days, when the conceptus causes a soft, thin walled cornual swelling this swelling slowly until about 30 days (organo-genesis phase) after day 30, faster growth and the swelling extends to the tip of the pregnant horn
The horn involved is not necessarily the one that produced the ovum because of the extensive mobility of the conseptus within the horns and uterine body before implantation (day 12-14), but most pregnancy are in the right horn
Twins are usually disposed at the base of each horn 2 groups of endometrial cups (if both twins are in the same horn, only 1 set of cups will be present)
Vagina Becomes progressively paler and dryer and is covered by thin, sticky mucus the external opening is gradually filled by a plug of mucus
Cervix Small, tightly closed and points eccentrically
days 40-120 of gestationOvaries Multiple follicular development one/both ovaries become temporarily larger than during
heat ovulation, formation of accessory CL and luteinization of un-ruptured follicles by day 100, follicular activity usually and the CL begins to regress
Uterus Up to day 60, the conceptus completely occupies the pregnant horn after day 60, the body and then the non-pregnant horn are invaded by the allanto-chorion membrane the pregnant horn changes from transverse to longitudinal position in the abdomen by day 100, the fluid filled uterus is felt as a tense swelling on the pelvic brim
day120 of gestation – to parturitionOvaries Becomes smaller and harder (regression of CL and follicles) and are drown forwards and
downwards by the gravid uterusUterus Increased tension of the utero-ovarian ligament and the anterior border of the uterus sinks
forwards and downwards (distension of the uterus by the fetus and fluids)After 8 month, the fetus normally assumes an anterior longitudinal presentationExcept in very large mares, the fetus can be palpated during this periodSlight movements can be detected in the uterine arteries (less obvious than in cow)
Cow (R&O – 74)Ovaries = CL of pregnancy (CL verum) persists at its maximum size throughout all gestation → can
be distinguished from the fully developed CL of di-estrus – only in PM examination (the basic differences are that the CL vernum protrusion from the ovary surface is less marked and the epithelium over it is white and scarred)
= as pregnancy advances, the position of the ovaries changes (but also in non-gravid animals their location is not-constant):Heifer → generally situated on each side (or slightly below) the cornua – at the level of
the pelvic brim, and may lie in the pelvic cavityCow (multiparous animal) → often situated in abdominal cavity, 5-8 cm in front of
pelvis Due to the increasing weight of the uterus and hypertrophy of the ovarian and uterine
ligaments, the ovaries pass deeper and deeper into the abdominal cavity → from the 5th month to the end, it rests on the abdominal floor
= generally it is possible to palpate the ovaries up to day 100 → beyond that it is too deep to reach from the rectum, or may be confused with the cotyledons
Uterus Time Fetus size28 d. 0.8 cm
longAmnionic sac = spherical, 2 cm and occupies the free portion of gravid hornAllantoic sac = 18 cm long, width is negligible (fluid is insufficient to distend
it) and it occupies the whole gravid horn35 d. 1.8 cm
longAmnionic sac = spherical, 3 cm and still occupies the free portion of the gravid horn
60 d. 6 cm long Amnionic sac = oval, transverse and 5 cm → the free part of gravid horn is distended to 6.5 cm (2-3 cm in non-gravid) → may be recognized at palpation
80 d. 12 cm long
The free part of gravid horn is distended to 7-10 cm (the other one is only a little greater than normal)
90 d. 15 cm long
Uterine distension can be detected with accuracy and in most it is still high up (at the pelvis brim)
The gravid horn is 9 cm wide (the non-gravid 4.5 cm)4th mo. Uterus sinks below the pelvic brim (the cervix lie on the pelis brem), and the
distension is less recognize (fluid gravitates towards the extremities of the horn)Non-gravid horn = the extent to which the allanto-chorion sac occupies the non-gravid horn varies
greatly and in most cases it participates in placentation (its cotyledons grow and the placenta is also connected to it)
Caruncles = hypertrophy during pregnancy, but vary in their size at various stages of pregnancy and between individuals (probably due to difference in number) and also throughout the uterus (those situated above the gravid horn are larger than those situated in the extremities, and those in the gravid horn are larger than those in the non-gravid one) → they are about 5-6 cm in the end of gestation (in rare cases, when the non-gravid horn is un-occupied or it doesn’t play a role in placentation, they may be as large as 8x12 cm)
Uterine arteries = hypertrophy of the middle uterine arteries and a characteristic change in their pulse wave (pulse changes and instead of being normal it becomes a “thrill” or tremor may be detected earliest at 86 day it becomes constant after 175 day) → a difference between the 2 uterine arteries is usually recognized from 100 day and it indicates the side of the pregnant horn → in the end of gestation, the arteries become greatly hypertrophied and tortuous (distinctly felt with thickness of a pencil and a continuous tremor-like pulse)
Pregnant side = in dairy cows the right uterine horn is more often pregnant (60%), and the CL is usually in the side of the pregnant horn
Bitch (R&O – 101)Days Abdominal palpation18-21 Embryos are felt as a series of tense, oval distensions in the horns (those situated in the
posterior parts are most easily palpated)In fat or large bitches it is impossible to detect embryos at this stage
24-30 The distensions have become spherical and remain tense → easily recognized (some times the posterior ones are smaller than those in front)
35-44 Remain spherical until day 33 → the constricted portions between the fetus units dilated, becomes elongated and much of the tenseness is lost
The uterus comes in contact with the abdominal wall (visible abdominal distension in animal with multiple fetuses) → palpation of the fetuses themselves is not-yet possible
45-55 Rapid increase in fetuses size, and it may be possible to detect the posterior situated onesDuring this stage the uterus changes its position in the abdominal cavity → in animal with
multiple fetuses, each horn is an elongated cylinder (38-51 mm and 228-300 mm long) and consists of two segments: 1. posterior which lie on the abdominal floor and pass toward the margin of the liver2. anterior which lie dorsal and lateral to the other segment with its axis directed backward
– towards the pelvisIn the last stages, the uterus almost entirely fills the abdomen
55-63 Very easy detection (bitch fore parts should be raised – so the uterus moves back):High in the flank we feel the one occupying the horn apexIn the midline just in front of the pelvis brim is one with its extremity in the uterine bodyDigital extremities can be felt per rectum
Mammary gland
At 35 days in un-pigmented skin, teat becomes bright pink, enlarged, turgid and they protrude → persists until 45 days, when the teats become larger, soft and may become pigmented → at day 50, hypertrophy of the glands → progresses, and at parturition it comprises of 2 parallel, enlarged and edematous areas with a depression between them, extending from the pelvic brim to the anterior part of chest
2-3 days before parturition → a watery secretion → onset of milk secretion coincidence with parturition
Similar changes may occur in pseudo-pregnancy
Sow (R&O – 74)Day Cervix + vagina Cornua bifurcation Uterus Middle uterine artery0-20 No change can be felt
(similar to di-estrus)Becomes less distinct Slightly enlarges,
with soft walls to 5 mm
21-30 Cervix is softer -“- Walls are softer 5-8 mm 31-60 Cervix feels like soft-
walled tubular organHard to define and thin walled
to the size of the external iliac artery
60-end Piglets are felt here only at the end of gestation
Larger than external iliac artery and show strong vibration
“Maternal recognition of pregnancy” = (R&O - 63)Luteal phase of the estrus cycle is prolonged by the persistence of a single or a number of CL
→ progesterone concentrations remain elevated → result in negative feedback on the anterior pituitary → inhibition of follicular development and ovulation, and prevention of return to estrus (in poly-estrus animals = CL does not regress) → in many species the placenta subsequently replace or supplement the luteal source of progesterone (see question no. 32)
This maternal endocrine response is detectable before the blastocyst is attached to the endometrium by microvilli (which directly or in-directly prevent regression of the CL)
Time of maternal recognition of pregnancy:
Day of recognition Day of definite attachmentMare 14-16 36-38Cow 16-17 18-22Ewe 12-13 16Goat 17Sow 12 18
38. Signs of approaching parturition in domestic animals (P – 606)1. Mammary development (enlargement) and Secretion of colostrum
Mare edema of the udder + ventral body wall and substantial increase in size (just prior to labor) changes from straw color to cloudy-straw color (in the weeks preceding foaling) then it
changes to yellow or yellowish-white and becomes viscous in most mares, 1-4 days before parturition, the colostrum dries as a drop of wax at the end of each teat
Cow may not be shown until 2-3 weeks before parturition replaces the sticky serum that can be discharged from the udder (just prior to calving)
Heifer begins at 4th month of gestation, while in Goat udder may need to milked to relieve pressure – as parturition approachesSow becomes prominent and distended during the last 1-3 days (mainly in gilts) and a few
drops of clear or straw fluid can be obtained by manual pressure most sows will farrow within 6-12 hours (up to 24) after free milk flow is established
Bitch primiparous (1st pregnancy) = milk may be present up to 7 days prior to parturition multiparous = lactation usually occurs 24 hours before parturition
Queen begins to develop several days prior to parturition visible growth in the last 72 hours milk can be extruded 24 hours prior to parturition
2. Slight relaxation of the pelvic ligaments (sacro-iliac and sacro-sciatic) Mare relaxation of ligaments is much less obvious sign of close parturition some mare show
hollowing and softening of the area, accompanied by relaxation and lengthening of the vulva – about 4 hours before foaling
Cow (may be palpated) slight relaxation of pelvic ligaments and slight dropping of the muscles over this region slightly raises the tail-head (in some cow) calving usually occurs within 12 hours, when relaxation of the caudal border of the ligaments is complete
Ewe a. during the last 3 days of pregnancy, 2-3 low- amplitude contractions per hour (in-frequent), lasting longer than 5 minutes (usually relatively un-active uterus and cervix)
b. last 2 days, 2-3 motor-activity decreases for the next 12-24 hours, coincidence with an accelerated softening of the cervix (increased distensibility)
c. last 12-24 hours, motor-activity progressively and becomes almost continuous shortly before parturition
3. Rectal temperature Mare + Cow a weak indicator of parturition because of the great variability (during the last 48
hours before parturition) → Cow temp. about 0.5CMare temp. 2-3C
Ewe about 0.5C (below 39.4C), 48 hours before parturitionSow by about 1C (irrespective of the ambient conditions), 12 hours before parturitionBitch + Queen in at least 1-2C, 24 hours before (difficult to detect because it is transient)
4. Enlargement of the vulva5. Behavioral changes
Ewe develop premature maternal instinct and an increased interest in the lambs of other ewesGoat restless and hollows out a nestSow nervousness and nest building – 1 day before parturition in confinement they are
restless, urinate and defecate frequently, respiratory rate , bite the walls or surrounding objects, scratch the floor and rearrange the bedding material as farrowing becomes closer, this excitement gradually decreases and the sow recumbent
Bitch try to find a quite place in the house to establish their nest large Bitches may dig a large hole (as wolves do)
Queen try to find a quite place in the house to establish their nest
39. Hormonal control of gestationMare (R&O – 65)Ovulation + CL formation → plasma progesterone within 6 days and persist at about this level for
the first month of gestation (frequently there is a transient fall at about 28 day, followed by a rise)
In the early part of 2nd month the endometrial cups (12) are formed (invasion of fetal trophoblast cells into the endometrium densely packed tissue within the gravid horn) at the junction of the gravid horn and body → produce eCG (Eq. Chorionic Gonadotrophin), which is first demonstrated in blood 38-42 days after ovulation → max. at 60-65 days → after the max. it and disappears by day150 of gestation (eCG = PMSG = Pregnant Mare Serum Gonadotrophin)
eCG has both FSH-like and LH-like activity → it is assumed that together with the pituitary gonadotrophins, it provides the stimulus for the formation of accessory CL which starts to form at 40-60 days of gestation (a result of ovulation like di-estrus CL or luteinization of un-ovulatory follicles) → because of the presence of these accessory CL, the progesterone and maintain this level for 50-140 days → than it and by 180-200 days it is very low and remains so until day 300 → increases rapidly and reaches a peak just before foaling → after parturition, rapidly to very low levels
Oestrogens concentration during the first 35 days are similar to those of di-estrus (although the embryo produces oestrogen at 12-20 days) → and reach a plateau between 40-60 days at levels slightly above those that occur before ovulation (the rise is due to the increased follicular development associated with eCG production, and after day 60 it is due to the activity of the fetus or placenta) → max. levels at 210 days (the main source is the fetal gonads) → gradual toward foaling, and a rapid one post-partum
The main estrogens in the mare are oestrogen and ketonic steroid equilin (oestradiol-17, oestradiol-17 and equilenine are also resent)
Prolactin level show no-distinct pattern
Cow (R&O – 65)The main source of progesterone is the CL, and the placenta produces only small amounts:
→ up to 200 days, removal of the ovary containing the CL or the CL itself (surgically or by PGF2) usually results in abortion
→ after 200 days until just before parturition pregnancy usually continuousProgesterone levels during the first 14 days are similar to those of di-estrus (in non-pregnant it
from day 18 after ovulation) → slight and a rapid recovery→ remains at the same level up to 20-30 days before parturition →
estrogens concentration are low up to day 250 → and reach peak values 2-5 days before parturition → rapid 8 hours days before parturition to the low levels immediately post-partum
Both FSH and LH concentrations remain low during gestation with no significant fluctuationsProlactin remains low until just before calving → and peaks 20 hours before calving → back to
the low levels by 30 hours post-partumBo. placental lactogen present in the dam circulation at day 160 of gestation → rapidly to max.
levels between 200 and parturition (its role is un-clear, but it appears to have prolactin and growth hormone activities)
Ewe (R&O – 93)In pregnant ewe, CL persists and peak di-estrus progesterone levels are maintained (in non-pregnant
cyclic ewe, level rapidly just before the onset of estrus) → gradually to day 60 → considerable due to placental contribution, and the level remains high until the last week of pregnancy → rapidly at parturition
Progesterone level is significantly higher in multiple pregnancy since in late pregnancy the placenta produces 5 times more progesterone than the ovary
Oestrogen concentrations remains low throughout gestation → start to a few days before parturition → sudden at the time of lambing → rapidly post-partum
Prolactin level fluctuate during pregnancy → start to towards the end and peaks on the lambing day
Placental lactogen can be detected from 48 hours of gestation → and reaches peak by day 140→ gradually until lambing (its role is still un-clear, and it may have a role in the luteotrophic complex and in controlling fetal growth and mammary development)
Bilateral ovariectomy after 55 days will-not result in abortion, since by this stage the placenta produces most of the progesterone (but we must remember that the CL persists throughout gestation and regresses only at the time of parturition)
Goat (R&O – 94)As in ewe, in pregnant goat, CL persists and progesterone levels until a plateau is reached (in non-
pregnant goat, level around the time of estrus) → rapidly a few days before parturitionTotal estrogens are much higher than those in ewe = they gradually from days 30-40 of gestation
(in ewe they remain low until a few days before parturition) → peak values just before parturition (in ewe there is sudden at the time of lambing)
Prolactin levels remain low during gestation → rapidly just before parturitionBilateral ovariectomy at any stage of gestation will result in loss of pregnancy (unlike ewe, where
bilateral ovariectomy after day 55 will-not result in abortion) → the ovary is the main source for progesterone
Sow (R&O – 89)In non-pregnant sow, progesterone concentration falls rapidly 15-16 days after estrus, but in
pregnant sow – the CL persists and the progesterone level remains elevated → this level persists most gestation (although a slight fall on day 24) → rapidly just before parturition
The ovaries and CL are always necessary for the maintenance of pregnancy and the number of embryos does-not influence the progesterone concentration
Total oestrogen concentrations remain constant during pregnancy → 2-3 weeks before parturition and peak values a few days before parturition → rapidly after parturition
Bitch (R&O – 98)In pregnant bitch, progesterone levels are similar to those of non-pregnant (in non-pregnant bitch,
luteal phase is prolonged and progesterone levels persist for 70-80 days) → for this reason can-not be used for pregnancy diagnosis
From day 30 of gestation there is gradual in progesterone, so by day 60 levels are very low → sudden just before parturition → zero level just after parturition (in non-pregnant there is-no rapid and low levels of progesterone persist)
Total oestrogen concentrations are slightly higher in pregnant than in the non-pregnant, with evidence of some at the time of implantation → remain constant during the rest of gestation → 2 days before parturition and reach the non-pregnant levels by the day of parturition
Prolactin during the first half of the luteal phase in both pregnant and non-pregnant → much greater in the second half of the pregnant → sudden during the rapid in progesterone (1-2 days before parturition)
Relaxin can be detected in Labrador and Beagle at 20-30 days of lactation (absent in non-pregnant bitches at all stages of reproductive cycle)
The ovaries are always necessary for the maintenance of pregnancy, and even their removal at day 56 will result in abortion
Queen (R&O – 99)Ovulation occur 23-30 hours after mating → progesterone levels rapidly → peak values at 1-4
weeks of gestation → levels gradually → rapidly during the last 2 days of gestationCats are un-usual in that queen may continue to display estrus behavior and accept mating, even
though ovulation may have occurred and there is significant production of progesteroneAt 3-4 weeks of pregnancy occurs hyperemia of the teats (it is progesterone-dependent phenomenon
and seen also in pseudo pregnancy)There is conflicting evidence concerning the relative roles of the CL and placenta in the synthesis of
progesterone during pregnancy Relaxin is produced by the placenta (contribute to maintenance of pregnancy by inhibiting
uterine activity) and appears during the 3rd week of pregnancy → just before parturitionProlactin is produced during the last 1/3 of pregnancy → concentration at weaning
40. Clinical pregnancy diagnosis41. Laboratory pregnancy diagnosisMethods of pregnancy diagnosis are of 4 types:1. Management methods = Failure to return to estrus A 2. Clinical methods = Vaginal = Examination C
= Biopsy= Uterine artery (per vagina)
Rectal palpation = FolliclesUterine toneConceptus D
4. Laboratory methods = Progesterone concentration in milk or blood (plasma) B
Oestrogens in blood or urineIdentification of eCG E
Pregnancy Specific Protein-B (PSPB)Estrone sulfate (oestrogen) in blood or milk (cow); urine or milk (sheep, goat)Vaginal biopsyRadiographyRosette inhibition titer (RIT) testMeasurement of serum proteinsSerum proteins = Fibrinogen
C-reactive protein
A. Failure to return to estrus → False positive will occurs:a. Silent heatb. An-estrus as a result of lactation or environmental factorsc. Prolonged di-estrus but has-not conceivedd. Prolonged luteal phase associated with embryonic death (pseudo-pregnancy)e. Ovarian cysts
B. Progesterone concentration in milk→ Reasons for false-negative results are:
a. Mistaken identity of the animal (on the farm or in the lab.)b. Milk storage problems due to excessive heat or UV-lightc. Low progesterone production by the CL d. Inadequate mixing of milk so that a low fat sample is obtained
→ Reasons for false-positive results are:a. Animal with shorter than average inter-estrus intervals (when sample is taken 24 days after
insemination, if the cow is not pregnant she will already be in luteal phase of next cycle)b. Embryonic death (if it occurs after the day when milk was collected)c. Luteal cysts which produce progesterone
d. Incorrect timing of insemination (if sample is taken 24 days after cow was incorrectly inseminated in early or mid-estrus, than she will be in the next estrus – with a functional CL and elevated progesterone concentrations)
e. Pathological prolongation of the life-span of the CLC. Vaginal examination → false positive:
a. In early pregnancy the vagina is indistinguishable from that seen in di-estrusb. Prolonged di-estrusc. Pseudo-pregnancy (early embryonic death and retention of fetus due to persistent CL)
D. Palpation of the conceptus in Mare → false positive in rectal palpation:
a. Partially filled urinary bladder (during days 70-100)b. An inflated large colon (during days 90-120)c. Pyometrad. Pseudo-pregnancy (early embryonic death and retention of fetus due to persistent CL)
→ false negative in rectal palpation:a. Confusion over the service date (later than the one recorded)b. If the uterus is not palpated completely
E. Identification of eCG → false positive
Embryonic or fetal death (once the cups are formed they will persist and secrete eCG even if the fetus has died regress only at the original time of regression)
→ false negativeBlood sample taken too early or too lateProduction of low levels of eCG
Ultrasound methodsFetal pulse detector High-frequency (ultrasonic) sound waves emitted from a probe, placed in the exterior of the animal or in the rectum, are reflected at an altered frequency when they strike a moving object or particles, e.g. the fetal heart or blood vessels the reflected waves are received by the same probe and the difference in frequencies are converted into audible sounds
A-mode (amplitude depth analyser) A transducer head emits ultrasonic sound waved and receives the reflected sounds, which is shown as a one-dimensional display (on oscilloscope* or light- emitting diodes) of echo amplitudes for various depths
* an instrument that displays a visual representation of electrical variations on the fluorescent screen of a cathode-ray tube
B-mode (brightness) = real-time ultrasound or imaging The probe* (transducer) contains piezo-electric crystals which (when subjected to an electric current) expend or contract and produce high frequency** sound waves the probe is applied to the skin surface or inserted into the rectum, and the sound waves are transmitted through tissues a proportion of the waves is reflected back to the transducer (depending on the characteristic of the tissue) the returning echoes compress the same crystals result in production of electric pulses which are displayed as 2 dimensional display of dots on a screen liquids are black (non-echogenic) while solid tissue is white (echogenic) gel is applied to the tissue to eliminate air (gas reflect 99% of waves)
* linear probe = crystals arranged in side by side in lines rectangle field* sector probe = single crystal fan-shaped field** frequency = 1-10 MHz (lower frequency = better penetration, but poorer resolution)
42. Early pregnancy diagnosis in the cow (R&O – 80)
21 – 24day Blood sample taken at day 21 after estrus progesterone remain elevated
Progesterone crosses the mammary and appears in milk (fat) closely follow the changes in blood and show higher concentrations per volume unit than in blood
Assay of pregnancy- specific protein B (PSPB)
24 day Not very useful today
Palpation of the amnionic vesicle
End of 1st
monthHorns are gently palpated along their entire length the amnionic sac is felt as a distinct, round, turgid object 1-2 cm , floating in the allantoic fluid
Palpation of the allanto- chorion (membrane slip)
33 day This method depends on the fact that in cow, attachment of the allanto-chorion to the endometrium occurs only between the cotyledons and the caruncles and that the inter-cotyledonary part of fetal membrane is free
Pick up the gravid horn between 2 fingers just cranial the bifurcation gently squeeze the whole thickness of the horn the allanto-chorion is identified as a very fine structure as it slips between the fingers before the uterine and rectal walls are lost from grasp
Uterine horns 35 day Unilateral corneal enlargement and disparity in sizeThinning of the uterine wallFluid-filled fluctuation of enlarged horns
Palpation of fetus when the amnion losses its turgidity
45-60 day Amnionic sac becomes less turgid, and in some cases it is possible to directly palpate the developing fetus
Palpation of the caruncles / cotyledons
80 (90-100) day
First felt in the midline by passing down upon the uterine body and base of the horns (irregular folded surface)
Uterine artery (per vagina) 85 day Hypertrophy of the middle uterine artery until presence of vibrations (impossible in non-pregnant animal) become larger, but impossible to palpate once the has sunk into the abdomen (between 5-7 month)
Estrone sulfate in blood or milk
105 day Milk or blood increases levels throughout pregnancy
Palpation of the fetus 120 day Per rectumAbdominal ballottement 7 month Pressing the abdomen and flank with fists the object is
to push the fetus (floating in fetal fluids) away from the body wall and then identify it as it swings back against the fist which is kept pressed against the abdominal wall
**findings in rectal palpation = the ease of palpation depends on the size of the cow, the degree of the suspension of the uterus and the degree of relaxation of the rectum and uterine wall = see q. no. 37
**hormonal control of pregnancy = see question number 39
43. Pregnancy diagnosis in the ewe and doe (R&O – 94, 98; M – 1472, 1498)
Method Earliest timeRosette Inhibition Titer (RIT) test
24 hours Determine the immunosuppressive potential of anti- lymphocyte serum applied to determine the presence of an Early Pregnancy Factor (EPF)
Failure to return to estrus 16 – 19 days Marking by ram fail to be mark again after 16-19 days
Peritoneoscopy 17 – 28 days Direct inspection (under general anaesthesia) of uterus & ovaries with laparoscope (endoscope)→91%accuracy
Fetal pulse detector – rectal probe
20-25 (35-55) days
97% accuracy
B-mode ultrasound sector transducer probe
30 days The method of choice accurate + rapid for pregnancy diagnosis (30 days) and also determination of the number fetuses (optimal at 45-50 days) → the only accurate method for detectioning the no. of fetuses
Performed about 20 cm cranial to the udder and across the whole width
Vaginal biopsy (similar in sow – question no. 45)
<40 days The stratified squamous epithelium of vaginal mucosa is sensitive to hormonal changes during estrus cycle and pregnancy → accuracy with advancing gestation (<40 days 81%, >40 days 91%, >80 days 100%)
Estrone sulfate test in urine or milk
40-50 day Its level increases 40-50 days after conception and remains high throughout pregnancy
Uterine artery (per vagina) >50 days Palpation per vagina as they run outside the anterior vaginal wall at 10 and 2 o’clock positions → some enlargement after 50 days and 62% accuracy after 60 day
Fetal pulse detector – external probe
40-80 Applied to the skin surface of the abdomen just cranial to the udder (using transmission-gel) ewe sitting or standing characteristic sounds indicate the presence of fetal heart or vessels (heart rate greatly exceeds that of the mother, except in late gestation where it can be less than the mother) → between 40-80 days 60% accuracy, after 80 days – over 90%
Between 80-100 days this probe can also be used to differentiate between single and multiple pregnancy (not the precise number of lambs)
Radiography 70 days Accuracy with advancing gestation (66-95 days 52%, >96 days 100%)
Recto-abdominal palpation 70 days Involves insertion of a probe into the rectum and palpation of the abdomen while the probe crosses the uterus from side to side
Palpation of fetus >100 days Through the abdominal wallMammary gland -“- Development in primipara (1st gestation)Abdominal ballottement Ewe stands normally and the abdomen (just in front of
the udder) is lifted repeatedly the fetus can be felt dropping on the palpating hand
44. Pregnancy diagnosis in the mare (R&O – 68; M - 1479)
Method Earliest timeB-mode ultrasound 9 Black sphere of 3 mm Failure to return to estrus 16 days Marked mare (teaser stallion) fail to be
mark again 16 days after inseminationProgesterone in milk or blood
16-22 days Levels remain elevated
Uterine tone 17-21 days Uterine horns as tubular organs (if no-conceptual swelling is palpable, then this tone should be only interpreted as suggestive of pregnancy)
Uterine body and the non-pregnant horn remain tonic until at least day 50 of gestation
Palpation of conceptus 17-21 days At 17-21 days it is a small, soft swelling of 2.4-2.8 cm or as an apparent ‘gap’ in the otherwise tonic horn at day 30 it is 3-4 cm at day 40 it is 6-7 cm (tennis ball) later it is not possible to completely cup it in the palm
Identification of eCG 40-120 days Blood sampleOestrogens in blood 85 days Concentration exceeds the max. values
obtained in non-pregnant maresAbdominal ballottement days Pressing the abdomen and flank with fistsOestrogens in urine 150-300 daysVaginal examination (speculum or manual)
Vaginal mucosa is pale pink, mucus is scant and the cervix small and tightly closed the opening is gradually filled with thick tacky mucus mucus plugs the opening and points eccentrically
Fetal pulse detectorA-mode ultrasound**Follicles (found in rectal palpation) are normally present during the first 3 months of gestation**Twin conceptus can be identified up to day 60 after this, a single conceptus involves both horns
45. Pregnancy diagnosis in the sow (R&O – 90; M – 1494)
Rectal palpationDay Cervix + vagina Cornua bifurcation Uterus Middle uterine artery0-20 No change can be felt
(similar to di-estrus)Becomes less distinct Slightly enlarges,
with soft walls to 5 mm
21-30 Cervix is softer -“- Walls are softer 5-8 mm 31-60 Cervix feels like soft-
walled tubular organHard to define and thin walled
to the size of the external iliac artery
60-end Piglets are felt here only at the end of gestation
Larger than external iliac artery and show strong vibration
Method Earliest timeProgesterone level in blood 16 days Level remains elevatedB-mode ultrasound 18 daysRectal palpation 18 daysFailure to return to estrus 18-22 days Traditionally used but not-very reliableVaginal biopsy (similar to ewe)
18-90 days Histological assessment of the number of layers of the stratified squamous epithelium of the vaginal mucosa** (best performed 32-35 days after insemination)
Oestrogen in plasma 20 days Detection of oestrone-sulfate in pregnant animals (not found in non-pregnant) → highest levels (and optimal time for detection) is at 24-28 days
Uterine artery pulse 21 daysA-mode ultrasound 23 daysFetal pulse detector 28 daysExternal signs 42 days** Pro-estrus → estrogen predominate → rapid proliferation of stratum germinativum → so at estrus
there are up to 20 layersFrom the end of estrus and throughout the luteal phase → progesterone predominate → number of
layers , so by day 11-12 there are only 3-4 irregular arranged layers → only 2-3 layers in late di-estrus
With the onset of pregnancy → progesterone domination continues → by day 26 the typical histological picture is 2 parallel rows of epithelial cells with condensed darkly stained nuclei → this pattern persist until the final 3 weeks of gestation
46. Pregnancy diagnosis in the bitch and queen
Bitch (R&O – 101; M – 1506)
Days Abdominal palpation18–21 Embryos are felt as a series of tense, oval distensions in the horns (those situated in the
posterior parts are most easily palpated)In fat or large bitches it is impossible to detect embryos at this stage
24–30 Easily recognized (some times the posterior ones are smaller than those in front)35–44 The uterus comes in contact with the abdominal wall (visible abdominal distension in animal
with multiple fetuses) → palpation of the fetuses themselves is not-yet possible45–55 Rapid increase in fetuses size, and it may be possible to detect the posterior situated ones
In the last stages, the uterus almost entirely fills the abdomen55–63 Very easy detection (bitch fore parts should be raised – so the uterus moves back):
High in the flank we feel the one occupying the horn apexIn the midline just in front of the pelvis brim is one with its extremity in the uterine bodyDigital extremities can be felt per rectum
Method Earliest timeB-mode ultrasound 14 days Most accurate method for pregnancy diagnosisA-mode ultrasound 18 days With external probe (do-not perform to caudal because of
the urinary bladder )Fetal pulse detector 29 days External transducer, placed near the mammary
glandMammary gland 35 days Become larger, hypertrophy of the glands
2-3 days before parturition→ a watery secretion → onset of milk secretion coincidence with parturition
Similar changes may occur in pseudo-pregnancyRadiography 42-45 days Fetal sacs (23-25 days)
Displacement of intestine by gravid uterusIdentification of the uterusPresence of fetal skeletons (42-45 days)
Body weight >5 weeks Rapidly according to the number of fetuses (more fetuses more weight)
Abdominal distention >5 weeks In multiple pregnancy (if only 1-2 fetuses present or the bitch is fat or large distension may-not be noticed)
Distention can also be caused by pyometra (during pseudo-pregnancy), ascites, peritonitis with effusion, splenic enlargement and neoplasia (liver, abdominal lymph nodes or uterus)
Fibrinogen (serum proteins) Rise during pregnancy with peak values at 4 – 5 weeks (do-not occur in met-estrus in non-pregnant bitches)
C-reactive protein (serum proteins)
Rise in mid-gestation (probably due to damage caused by implantation of the fetuses)
Bitch is not poly-cyclic → pregnancy can-not be anticipated by failure to return to estrusPseudo-pregnancy is very common
The abdominal and subcutaneous fat depositions are often marked during pregnancy (stores of fat for the subsequent lactation, which is lost again during nursing period)
Queen (R&O – 105, M - 1506)Method Earliest time
B-mode ultrasound 1st weekAbdominal palpation 16-26 days Fetuses are identified as individual, turgid , spherical
swellingsUp to 13 days may be confused with fecal bolusesAfter 6 weeks, conceptuses markedly increase in size,
elongating and merging → more difficult to palpate (but by this stage there is significant abdominal enlargement)
Fetal pulse detector >3rd weekRadiography 42-45 days Displacement of intestine by gravid uterus
Identification of the uterusPresence of fetal skeletons (42-45 days)
47. Length of pregnancy in various species of domestic animals (M - 978)Days
48. Nutrition, handling and placement of the pregnant animals56. Care of parturient animals58. Periparturient care of the dam64. Health management of the periparturient cow and calf in large herds
Mare (M – 1482, R&O – 159)Mare should be taken to the foaling area 3-4 weeks before her expected foaling date, so she can build
up antibodies to the pathogens present in the environment (these antibodies will be passed to the newborn via colostrum)
Foaling box-stalls should be large (at least 3.5x3.5 m) → walls should be of solid construction, free of sharp edges and observation should be possible without disturbing the animal
Foaling area should have good ventilation and be well bedded with clean, dry strawIf the presentation is normal (two feet and muzzle at the vulva), then the mare is almost certain to
deliver the foal (an exception is dog-sitting presentation that only looks normal)As soon as an irregular presentation, position or posture is recognized, or if no progress occur within
10 minutes of the onset of straining → vet. exam.
Cow (M – 1470, R&O – 159)For nutrition, see question number 22Animal should gain weight before calving, but over conditioning will cause:
Excess fat deposition in the udder → lower milk productionExcessive fat deposition in the pelvis → may result in dystocia
Calving sheds, small pastures or other calving arrangement → must be clean, dry and protected from the weather (calving in clean area, separated from the rest of the herd helps to reduce disease)
In large herds, it is desirable to have several small calving pastures to allow weekly rotation to avoid building of disease-causing organisms
When calving stalls are used, they should be cleaned + disinfected between calvingClose observed for labor (necessary to determine when delivery should be assisted)Feeding pre-parturient cows at 1100 – 1200 am. and again at 930 – 1000 P.M → 75% of cows will calve
between 700 am 700 pm (problems are more likely to be identifies and assistance are more likely to be available)
If after 12 hours of restless there is no straining or if a cow comes into a normal 2nd and there is no progress after 1 hour of straining → vet. exam.
Ewe (R&O – 159)For nutrition, see question number 24Pregnant ewe should be kept in a handy yard or in a lambing yard or pan
Sow (R&O – 159)For nutrition, see question number 23Should be well washed and introduced into a farrowing crate – several days before the expected
farrowing → most farrow at night and there is great loss due to overlying by the sow (more than ½ the deaths up to weaning occur 48 hours after birth)
49. Mechanism of parturition (P – 607)On the basis of mechanical events, we can divide parturition into 3 stages:I = starts with increasingly frequent uterine contractions, which raise the intra-uterine pressure and
causes dilation of the cervix → ends before the rupture of the allantoic membraneII (fetal expulsion) = escape of the allantoic fluid and then amnionic fluid, and some vigorous
straining leading to the eventual delivery of each offspring → the birth canal includes the cervix, vagina and vulva – each of which can expand sufficiently to accommodate the fetus
III = rupture of the umbilical-cord and expulsion of the fetal-membranes (placenta) from the uterus**The II + III stages are repeated for the delivery of each fetus in the litter**Any event occurring before the II stage is regarded as pre-partum, and any event occurring after
completion of the II stage is regarded as post-partum
See questions 51-55 for individual animals
50. Physiology of parturition – generally (R&O - 141)EweBefore 120 days of gestation, most of the fetal cortisol is derived from ewe (trans-placental transfer)After 120 days (20-25 days before parturition) there is dramatic in fetal cortisol concentration
(originate from fetal adrenal) → peak 2-3 days before birth → decline 7-10 days post-partumLast 10 days of gestation there is CRH (Corticotrophin-Releasing Hormone) secretion from the
fetal hypothalamus (and may-by also the sheep placenta can secrete CRT)Endogenous opioids (effect the fetal hypothalamus rather than the pituitary), Pro-Opio-Melano-
Cortin (POMC) and arginine vasopressin may also play a role in stimulating ACTH secretion since they increase towards the end of gestation
Maternal cortisol only around the time of parturition, while at the same time, the binding capacity of the fetal plasma increases and the amount of free cortisol in the fetal circulation → reduce the negative feedback effect on the secretion of ACTH → ACTH secretion With advanced age, the fetal adrenal becomes more responsive to ACTH and secreteACTH is one of the factors influencing maturationThe in fetal cortisol stimulate the conversion (enzymatic) of placenta-derived progesterone to oestrogen (cholesterol pregnenolone progesterone 17-hydroxy-progesterone androstenedione oestrogen)The estrogens have 3 effects:
1. Oestrogens have direct effect on the myometrium and increase its responsiveness to oxytocin → oxytocin (together with mechanical stimulation) stimulate release of PGF2 from the myometrium
2. Alter the structure of collagen fibers → softening of the cervix3. Act on the cotyledon-caruncle complex and stimulate production of PGF2 (progesterone
and oestrogen activate enzyme phospholipase convert phospholipids to arachidonic acid arachidonic is converted under the influence of prostaglandin synthetase enzyme into PG + PGF)
The uterus produce 2 prostaglandins = PGF2 in the endometrium and PGI2 (prostacyclin) in the myometrium (during fetus expulsion)
Prostaglandins are soluble in fat and water so they can pass from cell to cell via cell membrane or via extra-cellular fluid and have a wide range of action:1. Smooth muscle contraction (PGF2 is intrinsic stimulation of smooth muscle) → force the fetus
towards the cervix and vagina where it will stimulate sensory receptors and initiate Ferguson’s reflex** → release oxytocin (posterior pituitary) → further stimulation of myometrial contractions and release of PGF2
2. Luteolysis → Progesterone level in blood3. Softening of cervical collagen4. Stimulate sooth muscle cells to develop gap junctions (areas of contact) → allow the passage of
electrical pulse and ensure coordinated contractions** Ferguson’s reflex = stimulation of mechano-receptors in the vagina, cervix and uterus – by
mechanical distension
CowBetween 150-200 days of gestation, placental estrogens act on the fetal cotyledons → release
PGF2 → CL regresses and the placenta produces most of the progesteroneThe endocrine changes are very similar to those in the sheep and goatGoat
CL provides the progesterone necessary for maintenance of gestationFetal cortisol → placental 17-hydroxylase → diverts the synthesis of progesterone by the CL
into oestrogen → changes in oestrogen/progesterone ratio stimulates synthesis of PGF2 (as in ewe) → luteolysis + further in progesterone (must disappear before parturition can occur)
The endocrine changes are very similar to those in the sheep and cowSow
CL provides the progesterone necessary for maintenance of gestation throughout its entire duration
Cortisol in fetal plasma → maternal blood cortisol , oestradiol , PGF2 and progesterone The endocrine changes are very similar to those in the sheep
MareThe mechanisms responsible for initiation of parturition are not well understood as those of
ewe…., however it is likely that the fetus is responsible for the initial trigger mechanism, since the fetal adrenal undergoes rapid hypertrophy immediately before parturition and fetal plasma cortisol levels nearly 10-folds during the last 8 days before parturition
In newborn, -endorphin (produced in neural synapses, where they modulate the transmission of pain perception rise the pain threshold + produce sedation )→ may involve in triggering parturition or are produced in response to the act of parturition (not fully understood)
In maternal circulation, progestogens (progesterone + progestins) remain low from mid to last 2-3 month of gestation → +peak 48 hr pre-partum → rapidly to low levels at time of parturition
Oestrogen during the last days of gestation (in other species it ) reaching low levels at parturition
BitchThe mechanisms responsible for initiation of parturition are not well understood as those of
ewe….,Cortisol before parturition → peak 8-24 hours pre-partum
Progesterone gradually from about 30th day of gestation → rapidly 12-40 hours pre-partum (due to in PGF-metabolites 48 hours before parturition release luteolytic amounts of PGF2)
Oestrogens remain at constant level throughout pregnancy → days pre-partum → reach non- pregnant values at the time of parturition
Prolactin as progesterone 1-2 days pre-partum (not known if prolactin plays a role in parturition)
QueenThe mechanisms responsible for initiation of parturition are not well understood as those of
ewe….,Progesterone remains between 20-50 ng/ml in the first 2/3 of gestation → gradually towards
parturition → just before parturition rapidly → almost zero at the time of parturitionOestradiol slightly just before parturition
RelaxinRelaxin generally influence the pubic symphysis, pelvic ligaments, cervix, myometrium, mammary
gland.
Sow = produced mainly by CL → stimulates cervix growth during late pregnancy, relax the cervix at parturition (also influenced by oestrogen/progesterone ration), influence myometrial activity ( frequency + amplitude of contractions)
Cow = produced mainly by CL and just before calving → cervix relaxation at termMare = produced by placenta from days of gestationBitch = produced by placenta from 4 weeks of gestation and remain elevated until termCat = produced by placenta suddenly from 23 days of gestation peak at 36 days
dramatically just before parturitionSheep = may-not be produced, so cervix relaxation may-not be relaxin-dependent
51. Normal parturition in the cow Signs of approaching parturition – question no. 38 (P - 606)1. Mammary development (enlargement) and Secretion of colostrum
Cow may not be shown until 2-3 weeks before parturition replaces the sticky serum that can be discharged from the udder (just prior to calving)
Heifer begins at 4th month of gestation, while in 2. Slight relaxation of the pelvic ligaments (sacro-iliac and sacro-sciatic) = (may be palpated) slight
relaxation of pelvic ligaments and slight dropping of the muscles over this region slightly raises the tail-head (in some cow) calving usually occurs within 12 hours, when relaxation of the caudal border of the ligaments is complete
3. Rectal temperature = a weak indicator of parturition because of the great variability (during the last 48 hours before parturition) → temp. about 0.5C
4. Enlargement of the vulva
Parturition (M – 1470, R&O - 161)
I 1-4 (6) hours Uterine contractions + cervix dilation → passage of the amnion and part of the fetus into the vagina
Great variation in symptoms = from none (mainly multi-gravid) to abdominal pain (usually heifer)
Occasional strainingFood is only “picked” and irregular ruminationAnimal may lower or kick at the belly, stand with back arched and tail raised, go
down and raise again frequentlyRestlessnessPulse may be increased The passage from 1st to 2nd stage is not clear-cut (as in mare)
II Heifer 1-4 hr.Cow <3 hr.
Abdominal contractions due to the fetus in the vaginal canal → first appears a water-bag → end with the expulsion of the fetus through the vulva
Straining is less frequent and animal may first remain standing → generally goes down during the passage of the head through the vulva→ remain recumbent until the calf is born (usually breast recumbence, but may lie on her side)
Pulse rate to 100 or moreLess intense but of longer duration than in mare → longer in heifer than cow, and
male take longer than femaleIn twin birth, intense straining of the 2nd calf begins 10 min. after delivery of 1st
The umbilical cord ruptures as the calf falls from the vulvaIII <12 hours
post-partumExpulsion of the fetal membranesPlacenta separation slower in cow than in mare → this whole stage is longer, but
the process of expulsion is similarIt is normal for the cow to eat the fetal membranes
52. Normal parturition in the mareSigns of approaching parturition – question no. 38 (P - 606)1. Mammary development (enlargement) and Secretion of colostrum
Edema of the udder + ventral body wall and substantial increase in size (just prior to labor)Changes from straw color to cloudy-straw color (in the weeks preceding foaling) then it
changes to yellow or yellowish-white and becomes viscous in most mares, 1-4 days before parturition, the colostrum dries as a drop of wax at the end of each teat
2. Slight relaxation of the pelvic ligaments (sacro-iliac and sacro-sciatic) = relaxation of ligaments is much less obvious sign of close parturition some mare show hollowing and softening of the area, accompanied by relaxation and lengthening of the vulva – about 4 hours before foaling
3. Rectal temperature = a weak indicator of parturition because of the great variability (during the last 48 hours before parturition) → temp. 2-3C
4. Enlargement of the vulva
Parturition (R&O – 160)I 4 hr. Beginning is best indicated by onset of patchy sweating behind the elbows and
flanks (occurs in most but not obligatory begins hours before parturition and increases as the stages progresses)
Initially the mare yawns (open her mouth), there is no obvious indication of pain, food is generally taken, respiration is normal, pulse is slightly raised ( during all the last period of pregnancy) and temp. may-be sub-normal (36.5– 37C) → as the stage advances, the mare becomes restless, tends to wander aimless around, the tail is frequently raised or held on one side, there may be swinging of the tail or slapping against the anus and kicking at the abdomen → mare become very restless (twitches, standing on hind-limbs, going down on knees or sternum and raising again, looking at the flank…) → the stage ends with rupture of the allanto-chorionic membrane and the escape of urine-like, allantoic fluid from the vulva
II 17 min. (10-70 min.)
Starts by appearance of the amnion or beginning of forceful, frequent straining → very soon after straining begins, the mare goes-down and lie on one side with her limbs extended ( generally remains in this position until the foal is born) → the appearance of the water bag (amnion) is quickly followed by appearance of a digit and straining occur at regular intervals (each 3-4 powerful efforts are followed by a period of rest of about 3 min.)
One forelimb proceeds the other one by 7-8 cm and this position is maintained until the head is born (significant because it indicates that one elbow passes the bony pelvic inlet before the other = minimum obstruction) → during its delivery, the head is usually in oblique position but may be transverse (cheek is lying on the limbs)
The longest and greatest effort is associated with the birth of the head → the chest presents less difficulty → hips slip-out easily → usually the foal is born within the amnion, which is ruptured by the movements of the fore-parts of the fetus (respiratory movements may be seen within the intact amnion) → after foal expulsion, the mare may remain lying on her side exhausted for up to 30 min.
As the foal is born, the umbilical cord is intact, and it ruptures (5-8 cm beneath the belly) only as the result of movement by either mare or foal
III Within 3 hr’s post-partum
No straining → expulsion by myometrial contractions → the membranes are passed with the allantoic surface (smooth and shiny) of the allanto-chorion – on the outside (indicates that the separation was complete before expulsion begins)
53. Normal parturition in the sowSigns of approaching parturition – question no. 38 (P - 606)1. Mammary development (enlargement) and Secretion of colostrum = becomes prominent and
distended during the last 1-3 days (mainly in gilts) and a few drops of clear or straw fluid can be obtained by manual pressure most sows will farrow within 6-12 hours (up to 24) after free milk flow is established
2. Rectal temperature = by about 1C (irrespective of the ambient conditions), 12 hr pre-partum3. Enlargement of the vulva4. Behavioral changes = nervousness and nest building – 1 day before parturition in confinement
they are restless, urinate and defecate frequently, respiratory rate , bite the walls or surrounding objects, scratch the floor and rearrange the bedding material as farrowing becomes closer, this excitement gradually decreases and the sow recumbent
Parturition (R&O - 166)I Uterine contractions + cervix dilation→ passage of the amnion and part of the fetus into the
vagina. 60-75% farrow at nightII + III
Abdominal contractions due to the fetus in the vaginal canal → end with the expulsion of the fetus through the vulva + Expulsion of the fetal membranes
Fetal membranes of adjacent piglets are usually fused → individual or aggregated after birth may be expelled during the 2nd phase as well as after the birth of the last fetus (so it is un-realistic to separate the 2nd and 3rd stages)
Sow in late pregnancy are mostly asleep in lateral recumbency → become restless 24 hours before parturition (1st stage pains) accompanied by bed- making activity → the intense activity is followed by recumbency and rest, but after some time – bedding activity resumes (there are several alternating periods of rest and bed-making) → in the hour preceding the birth, the sow settles quiet into lateral recumbence (sow usually remain in lateral recumbence but gilts may get up after the birth of the 1st or 2nd , or change from side to side, or from lateral to ventral recumbency)
After the pre-partum quiet period, there is intermittent straining accompanied by paddling leg movements → passing of small amount of fetal fluid and marked tail twitching → birth of 1st piglet → piglets are usually delivered at intervals of 15-20 minutes
The greatest effort is over the 1st piglet → next fetuses being expelled more easilyThe allanto-chorion and amnion usually rupture as the fetus passes the birth canal, but
occasionally piglets are born within the amnionFetal membranes tend to be expelled as 2-3 masses of joined allanto-chorions, and one or more of
the masses commonly pass before all the fetuses are born, but the larger mass is usually passed out 4 hours after the last piglet
After all the piglets have been expelled, the sow usually stands-up and micturates a large amount → lie down again (some times very clumsily) and remain quietly for a long period and allow the piglet to suck
54. Normal parturition in the ewe and doeSigns of approaching parturition – question no. 38 (P - 606)1. Mammary development (enlargement) and Secretion of colostrum =
Goat udder may need to milked to relieve pressure – as parturition approaches2. Slight relaxation of the pelvic ligaments (sacro-iliac and sacro-sciatic) =
Ewe a. during the last 3 days of pregnancy, 2-3 low- amplitude contractions per hour (in-frequent), lasting longer than 5 minutes (usually relatively un-active uterus and cervix)
b. last 2 days, 2-3 motor-activity decreases for the next 12-24 hours, coincidence with an accelerated softening of the cervix (increased distensibility)
c. last 12-24 hours, motor-activity progressively and becomes almost continuous shortly before parturition
3. Rectal temperature = Ewe about 0.5C (below 39.4C), 48 hours before parturition
4. Enlargement of the vulva5. Behavioral changes =
Ewe develop premature maternal instinct and an increased interest in the lambs of other ewesGoat restless and hollows out a nest
Parturition (M - , R&O - 166)Course is very similar to cow, except that the incidence of twining and even triplets is higherSpontaneous birth may occur despite retention of a forelimb
I Uterine contractions + cervix dilation → passage of the amnion and part of the fetus into the vagina
II 1 hour Abdominal contractions due to the fetus in the vaginal canal → end with the expulsion of the fetus through the vulva
III 2-3 hours Expulsion of the fetal membranes
55. Normal parturition in the bitch and queenBitchSigns of approaching parturition – question no. 38 (P – 606)1. Mammary development (enlargement) and Secretion of colostrum
Primiparous (1st pregnancy) = milk may be present up to 7 days prior to parturitionMultiparous = lactation usually occurs 24 hours before parturition
2. Rectal temperature = in at least 1-2C, 24 hours before (difficult to detect because it is transient)3. Enlargement of the vulva4. Behavioral changes
Try to find a quite place in the house to establish their nestLarge Bitches may dig a large hole (as wolves do)
Parturition (R&O - 165)I 12
hoursUterine contractions + cervix dilation → passage of the amnion and part of the fetus into
the vaginaBitch is restless, refuse food and pantMyoelectrical activity starts 12 days before parturition (3-10 minutes that recur at low
frequency of max. 2.5/hr) → 48 hours before parturition intervals are shorten to <3 min (correlates with the in progesterone) → frequency as progesterone 12-24 hours before parturition
II + III
Abdominal contractions due to the fetus in the vaginal canal → end with the expulsion of the fetus through the vulva
Onset is indicated by straining (in most cases the bitch remains in her bed in sternum recumbency although sometimes she may stand and move about during straining efforts)
The water-bag of the 1st fetus appears at the vulva and attain the size of golf-ball → it is generally ruptured by the bitch who licks vigorously at her vulva → delivery of the head requires the greatest effort (as in other species) and in most cases the body follows easily → expulsion of 1st fetus may take up to one hour, but usually much faster) → as a rule, the bitch rests for a while after birth of the 1st puppy (lies and lick the young which soon begins to suckle), she pays frequent attention to her vulva and lick up any discharge, the umbilical cord is intact at birth of the puppy → quickly torn by the mother (bites it away) → the fetal membranes are expelled in 10-15 minutes and are promptly eaten by the bitch → straining starts-again after some time (½-2 hours) → time needed for delivery of 2nd fetus is usually shorter → may be followed by rest or by birth of the 3rd puppy
The stage of expulsion of the fetuses is most variable (one bitch may have her 1st puppy and then rest for several hours, then deliver 2-3 more very quickly and then rest again before expelling several more; another bitch may expel the fetuses at fairly regular intervals) → there is no-rule
Expulsion of the fetal membranes is also irregularUnlike sow, there is tendency to expel puppies from alternate hornsThe total time of this stage depends on the number of fetuses, but when the litter is within
the usual limits (4-8) it takes hours In bitch, much of the uterine discharge is dark-green color
Queen Signs of approaching parturition – question no. 38 (P – 606)1. Mammary development (enlargement) and Secretion of colostrum = begins to develop
several days prior to parturition visible growth in the last 72 hours milk can be extruded 24 hours prior to parturition
2. Rectal temperature = in at least 1-2C, 24 hours before (difficult to detect because it is transient)3. Enlargement of the vulva4. Behavioral changes = try to find a quite place in the house to establish their nest
Parturition (R&O - 166)I Uterine contractions + cervix dilation → passage of the amnion and part of the fetus into the
vaginaRestless, frequently visiting the site selected for parturition or hiding in it, occasionally lying
down and straining un-productively II + III
Abdominal contractions due to the fetus in the vaginal canal → end with the expulsion of the fetus through the vulva
Begins with straining in lateral recumbency → expulsion of the kittens is usually rapid with short intervals between each birth and completed within a few hours (pattern of fetal expulsion may be much more variable and in some cases part of the litter is born on one day and the reminder 24 hours or more later → if the queen is alarmed it may disrupt the pattern of birth, and she may move the kittens already born to a new place before resuming parturition
The placenta are usually expelled still attached to the fetuses or shortly afterwards → quickly consumed by the queen
Breakdown of the marginal haematoma results in pigment which gives a brown coloration to the discharge
57. Perinatal care of the calf (R&O – 179)64. Health management of the periparturient cow and calf in large herds1. Onset of spontaneous respiration
Normally within 60 seconds of expulsion If not = ensure upper respiratory tract is clear of fluid, mucus and fetal membranes (with the aid of
fingers or with a simple suction device)= elevation of the rear of the calf result in escape of fluid = vigor rubbing of the chest with straw or towels (stimulate respiration)= portable oxygen cylinder and resuscitator= Respiratory stimulants as coramine and adrenaline → not very useful
-“- a mixture of solutions of crotethamide and corpropamide (placed on the tongue) → can help in some cases
If resuscitation does not result in spontaneous respiration in 2-3 min., it is un-likely that the newborn will survive – even if there is good pulse
2. ThermoregulationFollowing birth the body temp. of the newborn quickly – before it eventually recovers (the
degree of fall and speed of recovery very from species to species and with the environmental temp.)
In newborn the metabolic rate is controlled by:Metabolic rate = increases to 3 times the fetal rate soon after birth depend on adequate
substrate and can only increase to a certain level (summit metabolism) → since glycogen and adipose tissue reserves are low, immediate and adequate food must be available
Reduce heat loss = newborn has little subcutaneous fat (poor insulation) and the body surface is wet (heat loss due to evaporation) heat loss is greater in smaller individuals because of greater surface area per unit of body weight
Thermoregulation can be improved by:Ensure adequate food intake Controlled environmental temp. Reducing heat loss by quickly drying the coat
3. UmbilicusLigation is necessary (usually passive rupture or by bites of dam)In foal, premature rupture must be prevented since the pulse can persist for up to 9 minutes after
expulsion (thereby ensuring adequate blood volume)The navel should be cleaned with an antiseptic solution dried antibiotic spray or dressing
4. Protection from an excitable or vicious dam
59. Postpartum period in the cow (R&O – 171)Involution (reduction in size of the genital tract)It occurs in decreasing logarithmic scale – greatest changes during the first days after calvingUterine (myometrial) contractions continue for several days (help to expel fluid and tissue debris)Shrinking and atrophy of uterus, horns, cervix………. and myofibrils reduce in sizeThere is positive correlation between prostaglandin and concentration and diameter of the uterine
horn (higher levels of PG more rapid involution)Factors influencing the puerperium:
1. Age = involution is more rapid in primipara (1st parturition) than pluripara2. Season of year = involution is more rapid in spring and summer3. Suckling/milking = results are contradictory (may be breed dependent)4. Climate = heat stress → accelerate and inhibit the speed of involution5. Peri-parturient abnormalities = dystochia, retained placenta, hypo-calcemia, ketosis, twin
calves and metritis → delay involution6. Delayed return to cyclic ovarian activity = inhibit involution
Restoration of endometrium Although placentation in cow is considered non-deciduous (in human + primates, the endometrium
shade all but the deepest layer after birth), there is a noticeable loss of fluid and tissue debris during the first 7-10 days (the discharge is named lochia) → contain fetal fluids, blood from ruptured umbilical vessels, parts of placenta and parts of the uterine caruncles (degenerative changes and necrosis of the superficial layers)
The lochia is yellowish-brown or reddish-brown and the volume differs between individuals → from 2 liters to zero (complete absorption of the lochia) → greatest flow 2-3 days post-partum, and disappears by 14-18 days
Normal lochial discharge does-not have an un-pleasant odorCaruncle and their blood vessels become constrictedRegeneration of endometrial epithelium (complete re-epithelialization takes more than 25 days)Factors influencing the puerperium:
1. Retained placenta and metritis → inhibit healing 2. Ovarian return to cyclic activity → may have positive effect
Elimination of bacterial contamination At calving and immediately post-partum, the vulva is relaxed and the cervix is dilated → allow a
wide range of bacteria to enter the reproductive tract (Corynebacterium pyogenes, E, coli, Streptococci, Staphylococci…..) + the blood, cell debris and sloughed caruncular tissue provide medium for bacterial growth → flora fluctuations due to spontaneous contamination, clearance and re-contamination during the first 7 weeks post-partum (bacteria decrease with time)
In most cases, the bacteria does-not cause metritis/endometritisThe main elimination mechanism is phagocytosis by migrating leukocytes → but also uterine
contractions, sloughing of carunclular tissue and uterine secretion assist in expulsion of bacteria
Early return to cyclic activity is probably important because the oestrogen-dominated uterus is more resistance to infection
Factors influencing the puerperium: 1. Magnitude of contamination = massive bacterial growth overwhelm defense mechanisms2. Nature of bacterial flora3. Delayed uterine involution4. Retained placenta5. Calving trauma to the uterus6. Return to cyclic ovarian activity
Return to cyclic activityDue to the prolonged period of inhibition during pregnancy (continuous negative feedback effect of
progesterone), the pituitary requires some time for recovery → due to the low or absence of gonadotrophins, the ovary is relatively quiet and the cow is in an-estrus phase
Opinions vary about the 1st estrus post-partum → the first sign of estrus is not always a true reflection of the cyclic activity (some show signs only at 2nd-3rd estrus)
Progesterone concentrations can be detected in milk → high levels at onset of cyclic activityAnterior pituitary release FSH during the first days post-partum, so with sporadic release of GnRH
there is gradual rise in plasma FSH → causes some follicular development → result in negative feedback by oestradiol and inhibin
The ability of the pituitary to release LH is much slower (although the early release of GnRH causes some rise in LH, it quickly returns to basal levels)
Summery = immediately post-partum there are no-clearly defined episodes of FSH or LH activity – irrespective of suckling, milking or other function → later, the level of FSH rises first followed by LH
= in milking cows, due to increased GnRH levels → increased basal levels of LH (together with increased frequency and amplitude of LH pulses) → peak in ovulation → after ovulation there is a luteal phase which may be of normal length with return to estrus after 18-24 days or it may be much shorter (these short luteal phase probably arise because of inadequate pre-ovulatory development of the follicle so that it either becomes luteinized in the absence of ovulation or luteinization is inadequate)
Most post-partum ovulations occur in the ovary contralateral to the previous gravid hornPGFM (prostaglandin metabolites) return to normal levels before the 1st post-partum ovulationStimulation of the teat and milk removal cause a rise in glucocorticoids → suckling delay the return
to cyclic activity (may be by releasing opioid peptides which influence the release of LH and GnRH) => prolactin has a similar role
Factors influencing the puerperium: 1. Peri-parturient abnormalities = may delay ovarian return to activity2. Milk yield = contradictory evidence 3. Nutrition = inadequate feeding (mainly energy) during the dry period and after calving →
delay4. Breed = longer delay in beef compared to dairy5. Parity = delay in primipara compared with pluripara – up to 4th lactation6. Season of the year = effect of photoperiod → darkness inhibit return 7. Climate = delay in tropical climates compared with temperate zones8. Suckling intensity and milking frequency = the greater frequency of milking and intensity of
suckling (no. of calves) → the longer period of acyclicity
60. Postpartum period in the ewe and doe (R&O – 177)Very similar to cow → the main difference is that parturition is followed by a period of an-estrus
(seasonal breeders)Involution Rapid shrinking and contraction of the uterus (mainly during 3-10 days post-partum) → complete
involution by 20-25 days
Restoration of the endometriumAs in cow, there are profound changes in the structure of the caruncles with degeneration of the
surface, necrosis, sloughing and subsequent regeneration of the superficial layers of the endometrium
Return to cyclic activityAlthough in temperate climates ewes normally become an-estrus after lambing, there is evidence on
ovarian activity (a few days to 2 weeks post-partum) → follicular growth is common but without ovulation (when it does occur it is usually associated with silent heat failure of follicular maturation and ovulation is probably due to deficient in GnRH inadequate release of LH to stimulate normal ovarian action)
61. Postpartum period in the mare (R&O - 176)Puerperium is shorter in mare than in cow, with rapid involution and relatively good conception rates
at the first post-partum estrusLochia discharge is relatively slight in most mares and usually ceases by 24-48 hours post-partum
(although in some cases it can persist for up to a week)Uterine horn shrinks rapidly (the non-gravid horn shrinks at a slower rate) → reach pre-gravid size
by day 32 post-partumThe cervix remains slightly dilated until after the 1st estrusOvarian return to cycle is rapid → foal heat 5-12 days post-partum (although conception rates at this
1st estrus are lower than at other times, a large number of mares are fertile – proves that the endometrium is capable to sustain pregnancy)
Endometrium is fully recovered by 13-25 days post-partumThere is nothing comparable with the degeneration and sloughing in the cow → small amounts of
villous debris are frequently attached to the maternal crypts but are removed by autolysis → the maternal crypts disappear as a result of lysis and shrinkage of the epithelial cells of the endometrium, condensation of their contents and collapse of the lumen of the crypts→ by 14 days the endometrium is quite normal
As in cow, bacterial contamination of the uterus frequently occurs (mainly hemolytic Streptococci and Coliform) → usually eliminated by the foal heat → if not, although may increase during di-estrus, they usually disappear at the 2nd post-partum estrus
Placenta retention → delay involutionExercise → hasten involutionThe process is more rapid in primipara (1st parturition) than in pluripara
62. Postpartum period in the sow (R&O – 178)It is important that the changes will occur rapidly, with a return to a normal gravid status, so that
pregnancy can be established as quickly as possible after weaning
Involution Completed by 28 days post-partum
Restoration of the endometriumOne day after farrowing, the uterine epithelium is low columnar or cuboidal and extensive folding
that is present during pregnancy → at 7 days, the epithelial cells are very low and flattened and show signs of degenerative changes (there is also cell division which is subsequently responsible for epithelial regeneration) → the process is completed by day 21 post-partum and is capable of sustaining pregnancy
Return of cyclic activitySuckling and subsequent weaning have a profound effect on return to activity and other puerpural
changes in the genital tract (owing to the time taken for the completion of the puerperium the later the time of weaning and hence the later the sow is served, improve fertilization rates and pregnancy rates) → in most cases there will be no return to estrus and ovulation until the piglets are removed
In general, the later the time of weaning, the shorter the time interval to the 1st estrusThe time to the 1st ovulation can also be shortened by temporary removal of the whole litter for
varying periods during the day (partial weaning) or the permanent removal of part of the litter (split weaning)
By 3 days post-partum, there is rapid regression of the CL of pregnancy and signs of cellular degeneration
During suckling there is considerable follicular activity (sometimes associated with behavioral estrus shortly after farrowing), but without ovulation → follicles become atretic
During lactation → LH secretion is suppressed (probably due to direct neural inhibition of GnRH) → follicular growth and ovulation is inhibited
Irrespective of whether weaning occurred at 3-5 weeks, most sow show a pre-ovulatory LH peak within 7 days of weaning (at the time of weaning there is transient rise in basal LH of about 2 days duration, but unlike cow, there is no consistent change in the episodic release of LH)
Prolactin concentrations are high during lactation → decline rapidly to basal levels a few hours after weaning
FSH concentrations rise 2-3 days after weaningInadequate nutrition (mainly severe weight loss) and season of the year → delay onset of cyclic
activity Exposure to a boar → accelerate onset of cyclic activity
63. Postpartum period in the bitch and queen (R&O - 179)Bitch Bitch is mono-cyclic → parturition is followed by an-estrus and the onset of the next heat is un-
predictableRegression of the CL of pregnancy is initially rapid so → later it is much slower (still found 3 month
later)The rate of involution is similar to other species, and by 4 weeks post-partum the uterine horns return
to their pre-gravid size The lochia discharge immediately post-partum is very noticeable because of its green color →
changes within 12 hours to a blood-stained, mucoid dischargeIn the non-pregnant bitch, the surface of the endometrium undergoes desquamation followed by
regeneration → repair completed by 120 days after the onset of estrusAfter pregnancy and normal parturition → the time taken for regeneration of the endometrium is
about 134 days (desquamation of the epithelial lining of the endometrium starts at 6 weeks post-partum and completed by 7 weeks the whole regeneration process ends by 12 weeks)
Queen Lactation will usually suppress estrus activity, but if the queen has no-kittens to suckle or only 1-2
kittens – she may show post-partum estrus 7-10 days after parturition
Obstetrics and Gynecology – final examinationM = the Merck veterinary manualR & O = veterinary reproduction & obstetrics (Noakes…)CAR = compendium of animal reproduction (published by Intervet)P = Physiology of small and large animals (Ruckebusch, Phaneuf and Dunlop)T = current therapy in Theriogenology (David A. Morrow)S = SlatterB = veterinary medicine (blood…)J = handbook of veterinary obstetrics – Jackson
66. Superfecundatio, superfetatio, pseudograviditasSuperfecundatio (R&O – 131)Fertilization of 2 or more ova during the same ovulatory cycle, by separate coital acts
Superfetatio (R&O – 132)The fertilization and subsequent development of an ovum when a fetus is already present in the uterus, a result of fertilization of ova during different ovulatory cycles and yielding fetuses of different ages
Pseudograviditas (R&O – 35, 36, 463, 476)Mare = Describe a syndrome in which non-pregnant mare that have been served do not return to estrusEarly embryonic death after 15 days of gestation with persistent CL-verum → prolonged luteal phase, the cervix remains tightly closed and the uterus is tense and turgid)If early fetal death occurs after formation of endometrial cups (at 36 days) → mare will either become an-estrus or come into estrus (if it comes into estrus, follicular luteinization occurs without ovulation and therefore the estrus is not fertile last until the endometrial cups regress spontaneously at 90-150 days because there is no-practical way of destroying the cups prematurely)Goat = Persistent CL → accumulation of sterile uterine secretion in the uterine lumen (hydrometra) → cyclic activity stops and abdominal distension (variable degree) → pseudo-pregnancyMore common in older goats (incidence increase with age)There appears to be an association to advancing the onset of cyclic activity before the start of the normal breeding season (by using progestogen sponges and eCG)If un-treated → pseudo-pregnant persist → goat will expel a large volume of cloudy uterine fluid (cloud-burst) around the time of normal kiddingTreatment with PGF2 or analogue → expulsion of fluid and estrus in 4 daysBitch =Most show pseudo-pregnancy during met-estrus, but sign and intensity are very variable → termed covert (hidden) or overt (visible) pseudo-pregnancyOvert = clinical signs range from slight mammary development and lactogenesis to bitch showing all the external signs of pregnancy (including imaginary parturition, nesting, loss of appetite, straining, emotional attachment to inanimate objects and heavy lactation)There is no-difference in the progesterone concentration between bitches with or without signs of pseudo-pregnancy it is likely that prolactin is responsible for initiating the changes → (there is negative correlation between progesterone and prolactin)Pseudo-pregnancy can be intensified or prolonged in bitches undergoing ovary-hysterectomyQueen = Sterile mating which successfully induce ovulation lead to pseudo-pregnancyDuring first 3 weeks of pseudo-pregnancy, progesterone concentrations are similar to those in pregnancy → levels and reach baseline by 7 weeks → estrus will usually occur shortly afterwardsNesting and milk production are un-common, but hyperemia of the nipples is usually evidentAppetite may with some redistribution of fat → lead to increase in abdominal size
67. Superestrus, graviditas extrauterinaSuperestrus (R&O – 680)Super-ovulation = accidental or planned production of more than one ovum at ovulationAccidental = can occur when cows are treated with large doses of FSH as a treatment for an-estrusPlanned = Production of a number of ova from 1 cow at the same ovulation period (for embryo transfer)Induced by Gonadotropins (eCG, FSH, hMG…) treatment is on day 9-14 (estrus = day 0) of a normal estrus cycle → 48-72 hours later, administration of prostaglandin (cause regression of the mid-cycle CL and induce estrus) → estrus occur 40-56 hours later (normal manifestation)
Graviditas extrauterina (R&O – 285)Spontaneous or faulty obstetric technique rupture of the uterus → depending on the size of the rupture and whether or not infection occurs – it may heal without problems or the fetus may escape to the abdomen → great variation of symptoms from no-symptoms shown (owner unaware of the incidence) to shock and fetal toxemiaIf no-symptoms shown, owner may be unaware of the incidence → the only evidence of it is the subsequent finding of uterine adhesion or of mummified fetus among the abdominal visceraWhen rupture occurs during parturition → fetus passes into the abdomen, parturition pain and straining stop and uterine inertia may be suspected (until a uterine expulsion proves otherwise)Causes to spontaneous rupture Uterine torsionCervical non-dilatationDistension due to twins in one hornHydrallantosisExcessive fetal size Breech presentation (fully occupies the maternal pelvic inlet when uterine contractions begin, the fetal fluids do-not have a way to escape hydrostatic pressure in the uterus )Causes to accidental rupture Correction of fetal position during dystociaTraction of fetus when the cervix is incompletely dilatedCareless use of obstetrics toolsExternal violence (parturient dam falls heavily, kicked, car accident…)
68. Embryonic mortality (R&O – 110)Embryonic and fetal loss
Causes of embryonic/fetal loss:Genetic factorsSingle gene defects (recessive or dominant)Polygenic abnormalitiesChromosomal abnormalitiesEnvironmental factorsClimateNutrition Stress Ovulation rateFailure of the normal feto-maternal recognition factorsUterine conditionsHormonesInfectious agentsTeratogens =Viruses = Bluetongue virus, Border disease virus, Bo viral diarrhea, Rift vally fever virus…..Plants = Lupins, Veratrum californicumOthers = hyperthermia, iodine deficiency
Detection of embryonic/fetal loss:Irregular extension of the inter-estrus periodSlaughter and correlating the number of embryos to the number of CL (disadvantage = sow must die and the pregnancy is lost)Per-rectum examination of the fetus (disadvantage = only in large animals and early loss is un-detectable)Doppler, A-mode and B-mode ultrasound
Sequence to embryonic/fetal deathResorption of embryonic tissues → animal returns to estrus (if there is no-other conceptus in the uterus)Death due to infection → pyometraDeath after fetal bone ossification had begun → complete resorption can-not take place → fetal mummificationFailure of an aborting fetus to be expelled → macerationAbortion (often caused by infectious agents)Stillborn (may occur as a result of developmental anomalies)
Mummification of a fetusFetal death after the beginning of bone ossification (without infection) → complete resorption can-not take place → fetal mummificationPapyraceous m. =Fetal fluids are resorbed and fetal membranes become driedThe uterus contracts on the fetus, which becomes twisted and contortedIn polytocous species, if mummification occurs only to part of the embryos → does-not interfere with the continuation of the pregnancy of the live fetuses and the mummified fetuses are simply expelled at parturitionCauses = Pig * Infection with SMEDI viruses (entero- viruses from 2 serological *groups with epizootic disease of pigs – characterized by Stillbirth, *Mummification, Embryonic Death and Infertility)*Uterine overcrowding in large litters *Placental insufficiency in large littersCat = Uterine overcrowding in large littersDog = CHV (Canine Herpes Virus)Ewe = twin/triplet when one of the embryo has diedMare = twin pregnancy (one fetus is usually smaller than the and dies)Cow = haematic mummification is more commonHaematic m. =Fetal fluids are resorbed and the fetus and its membranes are surrounded by a viscous, chocolate-colored material (it was thought that the color is due to pigments from blood hemorrhages – and hence the name now it is believed that the hemorrhage follows the fetal death rather than the cause)Etiology is un-known, but it has been suggested as: *Genetic (mainly since it is more common in some breeds and families)*Torsion of the umbilical cord as the primary cause of death*Hormonal anomaly (was induced by using oestradiol and trembolone-acetate)Occur following fetal death between 3-8 month of gestation → since there is no-fetal sign for the onset of parturition, the CL persists and the pregnancy will continue for un-predicted time (often diagnosed only when the cow is examined because of prolonged gestation period) → can be treated by inducing abortion by luteolysis (using prostaglandins) and the fetus is expelled in 2-4 days (prognosis for further breeding is good since there is no-intrinsic damage to the reproductive tract)
Maceration and Putrefaction (putrescentio) of a fetusFailure of an aborting fetus to be expelled (may be due to uterine inertia) → bacteria enter the uterus through the dilated cervix→ digestion of the soft tissues (by combination of putrefaction and autolysis) → living a mass of fetal bones within the uterus (sometimes become embedded in the uterine wall and are difficult to remove other than hysterotomy)Fetal maceration causes endometritis and there is severe damage to the endometrium → animal should be sent for slaughter. In later stages, signs of systemic illness are usually absent, although weight loss and decline in milk production may occur. When the fetus is macerated, there is usually a chronic, watery or mucopurulent discharge from the vulva over a period of several weeks or month.
72. Infectious causes of abortionAbortion = Termination of pregnancy after organo-genesis is complete but before the fetus can surviveCow (M – 989)Neospora Abortion between 4-6 month of gestation (fetus autolyzed)
Some calf survive paralysis or orientation deficitsNo treatment or prevention
BVD(Bovine Viral Diarrhea)
Infection of the fetus between 42-125 days of gestation fetal death and abortion or resorption, or fetal immuno-tolerance and persistent infectionInfection of the fetus after 125 days of gestation abortion or fetal immune-response may clear the virus
Herd vaccination and removal of persistently infected cattle
The virus is carried to the placenta by WBC placentitis within 2-16 weeks then infects the fetus and kills it within 24 hours abortion usually from 4 month to parturition (fetus is usually autolyzed with multifocal small necrotic foci in the liver and other organs)
Herd vaccine. (intra-nasal, modified live viruses or killed vaccines)
Leptospira interrogans Feed or water contaminated by dog, rat or wildlife, cow may be life-long carrier, urine and milk of the dam may be infective for up to 3 month….. placentitis fetus dies 1-2 days before expulsion abortion in last 1/3, 2-6 weeks after maternal infection (usually no lesions)
Eliminating source of infection and vaccine every 6 month
Brucellosis Enter via mucous membranes invade the udder, lymph nodes and uterus acute or chronic placentitis abortion or stillbirth 2-5 weeks after initial infection
active control (tests,slaughter) and vaccination
Mycosis (fungi) Aspargillus, Mucor, Absidia, Rhizopus enter through oral or respiratory lesions hematogenously to placenta severe, necrotizing placentitis abortion from 4 m.
Avoiding moldy feed
Actinomyces pyogenes Bacteria is present on mucous membranes of many normal cows, urine, abscess discharge enter bloodstream endometritis and placentitis sporadic abortion in last 1/3
No effective bactericide available
Trichomonas foetus Venereal disease mild placentitis usually results in infertility, but occasionally abortion in 1st half of gestation
Artificial insemination
Campylobacteriosis C. fetus veneralis = venereal disease usually causes infertility but may invade the placenta and fetus sporadic abortion between 5-8 month of gestationC. fetus fetus = transmitted by ingestion hematogenous spread to placenta mild placentitis extend to fetus may result in abortion with a live calf at expulsion
Artificial insemination and vaccination
Listeria monocytogenes Placentitis, fetal septicemia and dam may have fever and anorexia fetus retained for 2-3 days after death (extensive autolysis, liver is shrunk and contain pin- point abscesses) abortion at any stage of gestation
No effective bactericide available
Chlamydia psittaci Placentitis sporadic abortion after the 4th month of gestation (usually last 1/3)
Transmitted by ingestion hematogenous spread to placenta abortion in late pregnancy or stillbirth (ewe may develop metritis after expulsion )Tetracycline may prevent exposed ewe from abortion
Strict hygiene, and vaccination
Chlamydia psittaci(Enzootic Abortion of Ewes)
Necrotic placentitis (but fetus is not necrotized) late abortions, stillbirth or weak lambsExposure during early gestation abort late in that gestationExposure during late gestation abort toward the end of the next gestationCongenitally infected eweabort at end of their 1st pregnancyEwe seldomly abort from EAE more than once
Isolation of all inf. ewe +lamb, treatment with oxytetracycline, vaccine before breeding (killed ovine chlamyd.)
Toxoplasma gondii Exposure in early gestation resorption / mummificationExposure in late gestation abortion / peri-natal death
Once infect. ewe immune
Listeria monocytogenes
Abortion in late gestation (fetal liver may have small necrotic foci)
No effective bactericidal
Brucellosis B. ovis problem in ram but rarely cause abortionB. melitensis abortionB. abortus occasionally causes abortion in late gestation (placentitis, edema and necrosis of placenta)
Vaccine for B. melitensis
Salmonellosis S. abortus ovis, S. Dublin and S. typhymurium endemic in some parts of Europe, but elsewhere usually stress related most ewe are sick and febrile before abortion no specific placental lesions and fetus is autolyzed
Goat (M – 994)Chlamydia psittaci Necrotic placentitis (yellow necrotic foci) fetus may be
necrotized or not late abortionsNatural immunity lasts 3 years (older doe may be at risk)Exposure during early gestation abort late in that gestationExposure during late gestation abort toward the end of the next gestationCongenitally infected ewe abort at end of their 1st pregnancy
Isolation of all infected doe + treatment with oxytetracycline, ovine vaccine (killed ovine chlamydia vac.)
Toxoplasmosis Exposure in early gestation resorption / mummificationExposure in late gestation abortion / peri-natal death
Once infect. doe immune
Leptospira interrogans
Sheep are relatively resistant, goats are susceptible leptospiremia anemia, icterus, hemoglobinemia or febrile abortion
Eliminate infec. source +vaccine every 6 m.
Brucellosis B. melitensis abortionB. abortus occasional abortion Abortion may be accompanied by mastitis, lameness and doe may develop chronic uterine lesionsInfection of adult is lifelong (organism in milk)
Test, slaughter
Listeria monocytogenes
Sporadic abortion in late gestation (no specific fetal lesions) No effective bactericidal
Pigs (M – 994)Porcine Parvo-virus Asymptomatic in adults
Infection before 70 days of gestation mummification or increased number of stillborn (endometrium is-not affected no PGF2 release abortions are rare)
Vaccination and natural immunity is lifelong
Porcine Entero-virus Almost all herds are infected (asymptomatic) fecal-oral transmission mainly early embryonic death and stillbirth
No vaccine available
Pseudo-rabies Infection can be inapparent or cause respiratory and CNS signs in young pigFetal death at any stage of gestation + endometrial desquamation PGF2 release, luteolysis and abortion (mummification maceration and stillbirth also occur)As in other herpes viruses, natural infection can result in latency and carrier state recovered should be culled
Eradication program + vaccination
PRRS(Porcine Reproductive and Respiratory Syndrome)
Late abortions, stillbirth, weak neonatesIn the herd – respiratory disease, anorexia, vomiting and high prevalence of other diseases
Japanese B-Encephalitis Virus teratogenic and frequently causes hydrocephalus VaccineHog-cholera virus Severe maternal illness abortion VaccineLeptospira interrogans Most infections are asymptomatic abortion 1 – 4 weeks
after infection (abortus is autolyzed), but mummification, maceration, stillbirth and weak piglets are also seen.Carrier state can be eliminated by streptomycin (25 mg/kg)
Vaccination every 6 month + streptomycin in outbreak
Brucella suis Infected (venereal) sow abort at any stage of gestation due to endometritis and fetal infectionNo effective treatment found except control
Cow Genetic factors (most lethal genes cause early abortion or early embryonic death)Vitamin A (essential for proper growth) and E (antioxidant) deficiencyHeat stress → fetal hypotension, hypoxia and acidosisPyrexia → high maternal temperature Severe trauma (rare in Bo since fetus is well protected by amnionic fluid)Toxins =Ponderosa pine ingestion in late 1/3 (estrogenic material)Oxytropis or Astragalus (contain alkaloids that can affect the CL, chorio-allantosis and neurons abortion or deformation)Gutierrezia microcephalusCoumarins from rat poison, mouldy sweet clover or many grassesMycotoxins (mainly those with estrogenic activity)
Sheep Very similar to cowGoat Plant toxins
Dietary deficiency of copper (required for bone and blood formation because it’s a component of some enzymes), vit. A or magnesium (required for activity of many enzymes)Drugs as estrogens, glucocorticoids, phenothiazine, carbon tetrachloride or levamisole
Pig Heat stressCarbon monoxide (CO) toxicity due to faulty propane heaters Vitamin A deficiencyToxins =MycotoxinsCresol spray (used for louse control)DicumarolNitrates
Horse Twining (placental insufficiency ultimately causes abortion)Umbilical cord abnormalities as torsion due to abnormal lengthEctopic pregnancy
Bitch Breeding in the wrong time ( most of the bitches ovulate between 10 – 14 days after onset of proestrus, but it can occur in 5th or at day30, so if the breeding occur at days 12 – 16, it can be missed.
Cat Mating, not in the correct time (detecting proestrus or estrus is problematic)
74. Premature induction of parturition103. Induction of parturition172. Induction of parturition
Premature induction of parturitionMare (R&O – 148, CAR – 75)Indication =Ensuring birth will occur in the presence of a skilled assistance (close observation)Mares that had problems with parturition or needed surgical correction in the pastMares with serious problems (colic, endotoxaemia…) around the time of expected parturition in order to prevent further escalation of the problemRecommended to be performed only on =Mammary glands are developed and contain colostrum (the most important criterion) Ca content of secretion is useful to predict foal survivalSufficient gestation length not-before 320 days of gestationCervix should be soft and able to allow the insertion of 1-2 fingersMares that can be closely monitored after the inductionMethods = Oxytocin= cervix is ready im 120 IU to mare 360-600 kg foaling 15 min. later= cervix is not ready im 30 mg stilboestrol dipropionate in oil oxytocin 12-24 hours later (if cervix is ready)= 10-15 after oxytocin administration it is recommended to perform a 2nd vaginal examination to determine the foals position and posture= doses of less than 60 IU result in retained placentaDexamethasone = (quick-release synthetic corticosteroid) 100 mg/day for 4 days parturition 6-7 days after start of treatmentPGF2 = repeated inj. of 1.5-2.5 mg every 12 hours (may cause discomfort and dystocia due to position abnormalities)Fluprostenol = (analogue to PGF2) single dose (250 g to pony; 1000 g to thoroughbred) parturition within 0.5-3 hoursProgesterone = parturition 6-7 days after treatment
Cow (R&O – 149, CAR – 47)Indication =Advancing the time of calving to coincidence with the availability of pasture or according milk production demands induce calving in a certain, desirable periodEnsuring birth will occur in the presence of a skilled assistance (close observation)Immature dam, small pelvis or prolonged pregnancy over 280 days shortening gestation reducing birth weight of calf by (calf may be too large because during the last weeks growth rate is rapid)Diseased or injured cow where in order to prevent further escalation of the problem or where a live calf can be obtained before slaughterRecommended to be performed only on after 270 daysMethods = Corticosteroids = dexamethasone (short, medium or long acting – depending on time between treatment and effect) mimic the foal increase in cortisolPGF2 = During last weak of pregnancy most will calve within 48 hoursCombination of Corticosteroids and PGF2 = may be preferred because corticosteroids are needed for fetus maturation
Bitch and queen (R&O – 152)Un-successful Ewe and Goat (R&O – 151, CAR – 112)
Indication = Lambing under supervisionPost-partum flock management **Indications are limited since dystocia due to feto-maternal disproportion is un-common**It is not-possible to shorten gestation length appreciably without lamb mortalityRecommended to be performed not before day 144 of pregnancyMethods = Oestrogens = 2 IM inj. of 1-2 mg oestradiol benzoate 5-6 days before term= single inj. of 15 mg oestradiol benzoate 5 days before termCorticosteroids (as dexamethasone, flumethasone and betamethasone) single IM inj. within 5 days of term parturition within 2-3 daysACTH = stimulate endogenous corticosteroid production PGF2 = can-not be used because in sheep the placenta produces progesterone which blocks the action of PGF2
Sow (R&O – 150, CAR - 92)Indication = Farrowing under supervision Group farrowing allow cross fostering (greater survival of piglets from large litters or agalactia sows) allow all in all out management (easier to clean) group weaningIncrease reproductive efficiency by reducing the farrowing interval by a few daysMethods = Synthetic corticosteroids = inj. 75-100 mg/day on days 101-104 farrowing on day 109PGF2 or analogue = 10 mg PGF2 or 175 g cloprostenol IM inj. on days 112-113 farrowing 28 hours laterCloprostenol combined with oestradiol benzoate = 10 mg of oestradiol benzoate 24 hours before cloprostenol
Accelerating parturition – Sow (R&O - 152)Oxytocin = uterine inertia 1-2 IU repeatedly (doses of 10 IU cause uterine spasm and are contra-indicated)Carazolol (-blocking agent) = stress release of adrenaline uterus relaxation (during pregnancy, -receptors in the uterus become dominant)= if the -receptors are blocked with carazolol (0.5 mg/50 kg given at the beginning of labor) adrenaline will have little or no-effect on stressed animals myometrium uterus will remain its tone parturition will-not be delayed
Delaying parturition (R&O - 152)Clenbuterol = (-adrenergic agent) stimulate -receptors of myometrium reduce uterine contractions delay parturition for a short timeCow = provided that the cervix is-not fully dilated and 2nd stage has not commenced = injection of 0.3 mg clenbuterol hydrochloride (10 ml) followed (4 hours later) by 2nd injection of 0.21 mg (7 ml) inhibit calving for 8 hours after 2nd injection= Indication = Management toolEnsure improved relaxation of vulva and perineum in heiferSow = 150 g relaxation of mayometrium interrupt expulsion of piglet after several hours– return of contractility= 20-40 IU oxytocin reverse the effect of clenbuterol76. edema gravidarum, edema ante partumUdder edema (Mare, Cow, Ewe) (P – 18, 626)Begins 2-4 days before calving peak at calving decline 1-2 weeks after calvingIn the beginning of lactation, blood, interstitial tissue and lymph flow to the mammary gland increase the mass of the large fetus gradually compresses the afferent lymph vessels on the abdominal floor (where they leave the inguinal canal) mammary or ventral edema
In heifer, since incomplete development of mammary veins inadequate venous return and inability of the lymphatics to remove the large amounts of interstitial fluid during this time edemaEdema of the placenta (R&O – 129)Frequently accompanies placentitis (for example Brucella abortus infection) does-not cause dystocia but may accompany abortion or stillbirthDropsy of the fetal sacs (mainly Cow) (R&O - 129)Excessive quantities of fetal fluid in the amnionic (hydramnios) or allantoic (hydrallantois) sacs distension of the abdomen the later this condition occurs, the more likely the animal will survive to parturition gradual loss of condition very poor condition at parturition (in less severe cases), abortion or recumbency and deathMost occur in the last 3 month of gestation – cause is un-known (hereditary, low number of cotyledons, placental dysfunction doesn’t drain the continues produced fluid)Treatment = If animal is recumbent slaughterIf animal is near parturition caesarian section (important to allow the fluid to escape slowly to prevent hypovolemic shock)Dropsy of the fetus (R&O - 131)The form of the fetus and the degree of obstetric hazard are determined by the location and amount of the excessive fluid dystocia is due to the increased diameter of the fetusHydrocephalus = swelling of the cranium due to accumulation of fluid trocarization and compression, fetotomy or caesarian sectionFetal ascites = infectious disease of the fetus and developmental defects (as achondroplasia) dropsy of the peritoneum if fetus is near parturition, it my cause dystocia relived by incision in the fetal abdomen with fetotomy knifeFetal anasarca = excess fluid in subcutaneous tissue (mainly head and hind limbs) great increase in fetal volume dystocia
77. Inversio et prolapsus vaginae – etiology (R&O - 134)78. Inversio et prolapsus vaginae – methods of treatment Most common in cattle and sheep usually seen in mature female in the last 1/3 of pregnancy (more common in pluripara than primipara)The exact causes are un-clear, but several factors are believed predispose:Less efficient anatomical anchorage of the genital tract (cattle of beef breed – mainly Hereford)Endocrine imbalance in which oestrogen predominate (drug administration, excess in diet, feeding mouldy maize and barley or inherited) excessive deposition of fat in the pre-vaginal connective tissue + ligament relaxation increased mobility of the vaginaClose confinement of sheep or sheep fed on lush pasture and then restriction of exercise it is- not known whether sex hormones present in the herbage play a part or notFeeding with high-roughage diets (as silage, poor quality hay or root crops) In some bitches hyper-plasia of the vagina mucosa at estrus may protrude through the vulva (sometimes referred as vaginal prolapse, although such description is incorrect and is not comparable with the condition in other animals)Protrusion of the mucous membrane of the part of the vagina which lies just in front of the urethral opening → in severe cases the whole of the anterior vagina and cervix may protrudeThe earlier before parturition it occurs, the more serious it is likely to becomeMost cases in cow are seen in the last 2 month of gestation, and in sheep a few days before lambingIn the mildest cases, the lesions appear only when the cow is recumbent and when the animal rises the prolapse disappears → it tends to progress with time, and a larger bulk protrudes and does not disappear in standing position → this tissue, with its circulation impeded, is prone to injury and infection → the resulting irritation causes straining efforts → increases the degree of prolapse and so on…….→ eventually, the whole vagina, cervix and even rectum becomes everted (thrombosis, ulceration and necrosis of the prolapsed organ + toxemia and severe straining) → leads to anorexia, rapid deterioration of body condition and occasionally deathIn sheep, severe prolapse with heavy straining is-not well tolerated → death from shock, exhaustion and anaerobic infectionPremature parturition or abortion → relieves the condition and may lead to quick maternal recoveryPost-parturient prolapse of cattle is usually due to severe straining in response to vaginal trauma or infection → followed by Fusiformis necrophorus infection → high degree of irritation with frequent exhausting expulsion efforts
Methods of treatment
The aim is to arrest the process by early replacement and retention of the prolapsed portionEpidural-anesthesia (stop straining and desensitize the perineum for suture) → evereted mass is washed, dressed with antiseptic, lubricated and placed back → retained by: 1. Tape or stout nylon sutures which cross the vulva and inserted into the perineal skin (preferably over rubber tubes)2. Special vulval clumps3. Metal sutures4. In sheep – perineal wool (or a string attached to it) may be tied across the vulva5. Large safety-pinsTenesmus can be prevented for several days (up to more then a week) by artificial pneumo-peritoneum = sterile 10 cm needle passed through the abdominal wall at the sub-lumbar fossa connected to a pump which pump air into the peritoneal cavity – until the flanks are distended above the thorax (contra-indication is before parturition – because pneumo-peritoneum will prevent 2nd stage parturition)For cows showing recurrent prolapse, remote from parturition or post-partum it is recommended an almost complete surgical occlusion of the vulva = posterior epidural or local infiltration anesthesia strips of mucous membrane (1.2 cm wide) are dissected from the upper ¾ of each vulval lip the exposed areas are sutured by fine nylon sutures and a few mattress sutures of tape or stout nylon are deeply placed across the vulva to protect from the effect of straining the incision must heal and the suture must be incised a short time before parturition (Robert’s modification of Caslick’s operation)Sub-mucous resection (reefing operation) on the prolapsed organ → the object of the operation (which should not be performed later than 3-4 weeks from parturition) is to excise the protruding mucous (the protruding part) and then approximate the cut edges proximal + distal encircling incisions through the mucous membrane are made near made near the urethral opening and the cervix respectively (the interfering mucosa, in the form of half-moon, is removed) the cut edges are connected by absorbable material (Farquharson)Uses a special needle and a subcutaneous suture of nylon tape around the vulva to introduce the needle, two “stab” incisions (under epidural anesthesia previously induced to replace the vagina) are made in the mid-line (the upper one between the dorsal commisure of the vulva and the anus, while the lower is immediately beneath the ventral vulval comissure) the needle is inserted into the lower incision and passed subcutaneously until its point emerges through the upper incision a nylon tape in inserted into the needle-hole and then the needle is pulled back (leaving one side in the upper incision) the needle is inserted again into the lower incision and passes up the other vulval labium the upper free end of the tape is inserted into the needle-hole which is pulled back the tape encircles the vulva and its ends are tied with a simple knot (with such a degree of tightness that allow 4 fingers to be inserted up to their 2nd joint) the upper incision is sutured by 2 sutures, while the lower incision can be either left open or sutured → the vulval labia are not damaged, there is no-tissue reaction and it can remain in place for month → the knot can be opened before parturition to allow birth (Buhner’s method)Fixation of the cervix to the prepubic tendon with a nylon suture which is placed from the anterior vagina by means of 10 cm U-shaped cutting needle loaded with 0.9-1.2 m strand of nylon before inserting the suture (under epidural anesthesia)the bladder is pushed to one side (Winkler)In ewe, we can use a stainless-steel stay in U-shape – which is placed into the vagina the emerging ends are fastened by a string to other side of the wool of the gluteal region → this retainer has been improved by the development of a plastic spoon which is fastened in the same way or by a harness
79. Paraplegia gravidarum ante et post partumA large fetus may damage the obturator nerve which passes in the inner surface of the iliac shaftA large fetus is forced into the maternal pelvic may damage the lumbar nerves (pass over the lumbo-sacral joint to form the lumbo-sacral plexus) paralysis of the gluteal or obturator nervesGluteal paralysis = Seen in Mare and Cow (in mare it is followed by spontaneous birth) →dam has difficulties to rise and when she walks we see “weakness of the hindlimbs ” → later, atrophy of the gluteal muscle Good prognosis the disability usually disappears in a few weeks (complete recovery may take month) → if the dam can-not get up within a few days of parturition the prognosis is graveThe affected animal should be placed in a pen without ditches and obstacles and may be helped to riseObturator paralysis = More frequent in Cow than MareIt supplies the adductor muscles of the thigh:When both nerves are damaged → the legs abduct and the cow is unable to raise (if the cow is helped to its feet, the legs abduct again) → bad prognosisWhen nerve is damaged on one side → the cow also needs assistance to get up, but if the affected leg is prevented from sliding – she can stand (if the cow fails there is a risk of limb fracture or hip-joint dislocation) → good prognosis if the animal can walk with assistanceTying together both hind-legs (above each fetlock) prevents excessive abduction and secondary tearing of the adductor muscles or fracture of the femoral neck during attempts to standRapid improvement in most cases (a few days) and progress to complete recovery, but unless there is improvement within 4 days – recovery is unlikelyTreatment include good bedding to lie on, assistance to rise and stand during milking or suckling and as often as possible in other times, stimulation to walk (and prevention of falling), hindquarter massaged…..
81. Maternal dystocia – displacement of the gravid uterus (R&O – 210)Ventral hernia – Mare, Cow and EweHernia of the gravid uterus through a rupture of the abdominal floor (occur in very late pregnancy)Causes =Trauma (several blows on the abdominal wall)Non-traumatic (abdominal muscles become in some way so weakened that it is unable to support the gravid uterus)
The rupture is on the ventral aspect of the abdomen, a little to one side of the midline (Mare = left, Ru = right) – behind the umbilicusVisible as a local swelling that rapidly enlarges – until it forms an enormous ventral swelling extending from the pelvic brim to the xiphoid (the whole uterus and its content had passed out of the abdomen and occupy the subcutaneous) → complicated by edema of the abdominal wall due to pressure on veinsAs a rule, pregnancy is un-interrupted, but the condition (of both mother and young) gets worse when parturition comes (mainly in mare)In mare, if the foal is to be saved, it is essential to aid the mare the moment the expulsion forces start =Pulling the fetus if the it can be reachedIf the foal can-not be reached, the mare must be narcotized, turned on her back and the hernia reduced by pressure mare turned back to normal position before delivery is attemptAfter parturition and involution of the uterus, the hernia will be filled by intestine → after suckling the foal, the mare must be destroyedRu may give birth spontaneously despite severe ventral hernia, but animal must be closely watched for complications during parturition
Downward deviation of the uterus – SowAffected animal strain vigorously despite an empty vagina (the piglets did-not rich it yet) →→ at some point, the uterus (inside the body) deviated sharply in downward and backwards directionPredisposition factors are sow with deep bodies and large littersIt is very difficult to extract the obstructed piglets manually, and it may be necessary to insert an arm and flex the deviation back to normal position
Retroflexion of the uterus – MareColic in mares near parturition in which the foal occupied the maternal pelvis → can be pushed forward into the abdomen, but this manipulation provokes renewed colic, and the fetus soon regained the inter-pelvis positionIt can be treated by inj. of muscle relaxant (isoxsuprine lactate) at regular intervals – relived the colic and allowed the foal to move foreword in front of the pelvis → followed by normal parturition
Inguinal hernia – Bitch and QueenUnilateral hernia that may contain one or both uterine cornea → painful but without systemic disturbance → the mass is tense and irreducible, but with little tendency to strangulate (provided that intestines are-not involved)The course of the condition depends mainly on the degree of tension in the sac (influenced by its size and the number of fetuses involved) → death of the fetuses, resorption (of placenta and fetuses)…Treatment alternatives 1. Reduce the hernia and allow pregnancy to continue2. Enlarge the hernia ring by incision reduction of the hernia suture3. Dissect-out the hernia sac (cut near the body) including amputation of the involved horn/s suture (if the animal is pregnant also in the other horn inside the abdomen, it should-not be interfered)4. If the fetal development is sufficient (near term) the same as option 3, but to perform hysterotomy (cesarean section) it is possible to return the uterus back or remove it (hysterectomy)
82. Torsio uteri – etiology (R&O - 205)83. Torsio uteri – diagnosis84. Torsio uteri – methods of treatmentRotation of the uterus on its long axis with twisting of the anterior vagina
EtiologyA complication of late 1st stage or early 2nd stage parturition probably due to: Instability of the bovine uterus (uterus attachment) → can be accepted as a cause of torsion’s up to 180 but it can-not account for torsion’s of 360 or moreInordinate fetal movement which is part of the postural adjustment during 1st stage (in response to myometrium contractions)Excessive fetal weightPregnancy in one horn (rare in bovine twin pregnancy)In ewe, the anatomical attachment of the uterus (in sub-lumbar and not sub-iliac like in cow) is better and twining is very common, but still uterine torsion occur breed and fetuses in both horns do-not appear to effect the incidence
Clinical features About 75% of torsion’s are anti-clockwiseAlthough the uterus rotates about its long axis, in most cases the actual twist involves the anterior vagina (in minority of cases there is minimal distortion of the vaginal walls)The severity of the twist does-not directly affect the survival of the fetus (fetal death is caused by loss of fetal fluids or separation of the placenta)
SymptomsUp to the onset of parturition the signs are normal (usual signs of restlessness due to abdominal pain, myometral contractions and cervix dilation), and the only real sign symptom is that the period of restlessness is abnormally long or it does-not progress into 2nd stageIf the torsion does-not occur until the early 2nd stage, then after the restlessness – there will be a short period of straining, but they will stopIn severe cases, all parturient behavior stops, and unless the animal was closely watched – there might not be any sign that parturition had begun if the condition is-not relieved, the placenta will separate and the fetus will die persistent low-grade abdominal pain, progressive anorexia, constipation, secondary bacterial infection, maceration, putrefaction, maternal toxemia…….Diagnosis by palpation of anterior vagina walls in oblique spiral indicate torsion
Treatment 1. Rotation of the fetus inside the uterus Inserting a hand into the vagina (better under epidural anesthesia) holding it by its shoulder or elbow first maneuvers are designed to generate a gentle swinging motion before attempting to rotate it (in the opposite direction to the twist) after rotating the first 180, rotation is spontaneousSuccess depends on whether the cervix is sufficiently dilated to allow the hand to enter, and whether the fetus is aliveCare must be taken not to rupture the fetal membranes markedly reduces the fetal viabilityWhen the head of the live fetus is reached, pressing on its eyeballs will cause a convulsion reaction that can be translated into a rotationAbdominal ballottement might assist swinging the calf before attempting per vaginaProviding the fetus is accessible, Cammerer’s torsion fork (connected to canvas rope) can be placed on the extended limbsTorsion of the uterus anterior to the cervix or if the twist is 720 or more – can-not be treated by vaginal manipulation2. Rotation of the Cow’s body = correction by “rolling” (Reuff’s method)The aim is to rotate quickly in the direction of the torsion (while uterus remains relatively steady)Requires the assistance of at least 3 people One assistant holds the head while the front-feet are tied together and then the hind-feet are tied together (with separate ropes 2.5-3 m long) → each rope is held by 1 or more assistants which at a given signal pull it suddenly, so the cow is rapidly turned over from one side to the other → vaginal examination to examine if the correction has occurred (access to the cervix and may-be the fetus) → if there is no-relief, the Cow is slowly rotated back and the same procedure of rapid turning is repeated → if there again there is no relief and the spiral folds are tighter – the rolling is in the wrong direction and sharp rotation in to the other side is carried out (if the spiral folds are-not tighter, repetition of the original procedure is applied until the correction is achieved)If a cows extremity can be grasped while the cow is rolled, it will help to fix the uterus in placeSchafer modified this technique by application of a wide plank of wood (3-4 m long and 20-30 cm wide) to the flak of the cow (one end is on the ground) → an assistant stands on the wood, while the cow is slowly turned by pulling its legs (the wood fixes the uterus while the cow’s body is turned)3. Surgical correctionIf the case can-not be corrected by the previous methods → a laparotomy should be performed on the standing cow (at the left or right sub-lumbar fossa) → rotation of the uterus by intra- abdominal manipulationThe left flank approach is preferable (although loops of small intestine can be displaced on the left side of the abdomen) because a cesarean section may be required before the torsion can be corrected or after the torsion is corrected if the cervix does-not dilatePara-vertebral or field infiltration anesthesia → 15-20 cm incision in the left sub-lumbar fossa → the hand is inserted, the omentum is pushed and the direction of the twist is confirmed:Left twist the hand is passed down between the uterus and left flank the uterus is swinged and then rotated by lifting and pushing to the rightRight twist the hand is passed over between the uterus and right flank the uterus is swinged and then rotated by lifting and pushing to the leftAfter rotation of the uterus, if the cervix is only partially dilated, we can perform cesarean section or cervical section (fetus is pulled back to stretch the cervix deep incision at one point of the cervix gives immediate relief and allows delivery)
85. Initial examination during parturitionGeneral examinationCase history = date of expected parturition (pre-mature, prolonged), animal primigravid or multigravid, previous breeding history, general management during pregnancy, when did straining begin + nature + frequency, has water-bag appeared and when……Animal physical and general condition = If recumbent – is she resting or exhaustedPulse rateBody temperatureVulva = Is something protruding or notProtrusion of the amnion (if yes – is it moist and glistening and is fluid caught in it – if yes recently exposed, or dry and dark – as in prolonged cases)Protruding fetal parts (if yes – are they moist or dry)Nature of discharge = Blood (mainly if profuse – indicate recent injury to the birth canal)Dark brown smelly (a very delayed case)Degree of abdominal distension in Bitch and CatOnset of vomiting and great thirst – bad sign in Bitch
Detailed examination of large animals**Animal effectively restraint (twitch, epidural if necessary)Place sand on the floor because it may be slippery for the animalExternal genitalia and surrounding parts must be thoroughly washed The introduction of the hand through the vulva may provoke defecation in Cow – wash againBitch and Queen should be placed standing on the tableBitch and Queen hair may be clipped or not (depending on length) around the vulva
Vaginal examination by hand (large animals) or finger (small animals)Vagina empty or with newbornCervix degree of closure (if it is closed and occupied by sticky mucus – 2nd stage has not begun)Uterine torsion (does the vagina end abrupt at the pelvic brim and its mucosa spiral)Presentation of fetus
86. Basic causes of dystocia
There are several causes of dystocia:* Primary uterine inertia – an original defect in the contractile potential of the myometrium* Secondary uterine inertia – Inertia of exhaustion which results from dystocia → frequently followed by retention of placenta and slow involution of the uterus → predispose to metritis* Dystocia due to deviation of the head and neck of the fetus * Lateral deviation of the head – anterior presentation * Downward displacement of the head – anterior presentation* Dystocia due to deviation of the forelimbs* Dystocia due to pathological position of the fetus* Dystocia due to pathological presentation, position and posture of the fetus
Signs of dystocia
Cow* the cow has been in first stage labor longer than 6 hours* the cow has been in second stage labor for 2 hours and progress is slow or absent. * straining vigorously for 30 minutes without the appearance of calf.* incorrect presentation, position or posture.* the appearance of detached chorioallantois, fetal meconium or blood stained amniotic fluid at the vulva.* the amniotic sac is observed outside the vulva for 2 hours and delivery is not complete
Mare* minimal intervention and disturbance are indicated during stage 1, as mares may arrest the foaling process is seriously disturbed. * if fetal forelimbs don’t appear at the vulva within 5 – 10 minutes of rupture of the chorioallantois, manual vaginal examination is indicated.* if fetal membrane are retained, treatment should be instituted within 6 hours of foaling.
Ewe* the presence of a foul vaginal discharge or decaying placenta at the vulva.* an abnormal disposition of the fetus at the vulva. * a prolonged non-aggressive first stage of labor.* the ewe strains vigorously for 20 – 30 minutes or intermittently for 30 60 minutes but no fetus is seen.
Goat* An active labor for 30 minutes but no progress toward delivery.* an abnormal disposition of the fetus at the vulva.
Sow* Prolonged gestation more than 116 days.* signs of imminent birth but farrowing has not commenced. * appearance of blood-tinged vulvar discharge and meconium without signs of straining.* foul smell and discolored (brown, gray) vulvar discharge and decaying placenta at the vulva. * straining but not piglets born (nonproductive continuous straining lasting longer than 15 minutes or intermittent straining longer than 30 minutes.
* Cessation of labor for more than 2 hours after previous straining and delivery small number of piglets* litter size unexpectedly small. Bitch and queen* Gestation prolonged beyond the expected date of parturition* prolonged non-progressive preparation for birth (no parturition within 23 hours of the drop in rectal temperature)* vigorous straining for 1 – 2 hours without fetal delivery* the resting period during active labor exceeds 4 hours. * delivery of dead offspring. * green vaginal discharge (bitch), red-brown discharge (queen) but no fetus/es delivered so far. These discharge is normal once birth is underway. * black, purulent or hemorrhagic vaginal discharge.
87. Dystocia due to uterine inertia (primary and secondary) (R&O – 212)
Primary uterine inertia An original defect in the contractile potential of the myometriumIt is less common than secondary uterine inertia and it is seen most common in Bitch and Sow, occasionally in Cow and rarely to othersIt varies in degree from case to case (from cases in which 2nd stage does not begin, to cases where parturition is complete except for retention of one placenta in a polytocous birth)Causes =1. Inherited weakness of the uterine muscle (Scottish terrier, Ayrshire cattle…)2. Over-stretching of the myometrium by an excessive large fetus, twins, hydrallantois, or an un-usually large number of fetuses3. Toxic degeneration in bacterial infections4. Fatty infiltration of the myometrium5. Senility (rare)6. Abnormal chemical environment of the uterus = ratio between progesterone and oestrogen or lack of either oxytocin or calcium as in parturient hypo-calcemia:Inherited imbalanceLate-abortion or premature birthCongenital nervous problem or environmental disturbances which interfere with hypothalamic regulation of oxytocin secretion an release by the pituitaryExcessively small litter may fail to supply adequate endocrine contribution to terminate the pregnancy7. Uterus rupture or torsion on its long axis myometrial activity stopsDiagnosis =History = Mammary changes, ligament relaxation in the pelvis, restlessness due to abdominal discomfort → indicate that the 1st stage had passed, but no progress has been made In multiparous species, after a normal beginning of 2nd stage, all further activities has stoppedExamination of the birth canal and presentation of the fetus = opened cervix beyond which can be felt a fetusTreatment = Should be provided as soon as it is clear that the 2nd stage is present and that it is not proceeding normallyIn large, uniparous species → the fetal membranes are ruptured by vaginal manipulation fetal posture corrected (if necessary) fetus is delivered by gentle tractionIn Bitch → only 1 fetus is present in the uterus delivery by vectis (short metal rod with a loop at each end put on the cranium of long-nosed breeds of canine or feline allow traction or rotation of the fetus) or forceps per vagina→ multiple fetuses are present cesarean sectionPituitrin (posterior pituitary extract) can be inj. IM (provided the cervix is dilated, obstructive dystocia is not present and the uterus is-not over-distended)→ best result is obtained in early 2nd
stage (its disadvantage is that it may construct the cervix and by promoting placental separation of un-born fetuses it can reduce their survival if natural delivery does-not occur within 20 min. of inj. assisted delivery becomes more urgent)Ergometrine maleate may be given orally if the pituitary fails to bring down the last fetus or for expulsion of retained hemorrhagesIV inj. of calcium boro-gluconate can be given for sub-clinical hypo-calcemia in Bitch slowly initiate parturition (to prevent possible eclampsia, the dose should be repeated sub-cutaneously after parturition)Secondary uterine inertiaInertia of exhaustion which results from dystocia → frequently followed by retention of placenta and slow involution of the uterus → predispose to metritisCommon in all species and generally it can be prevented (depends on early recognition that parturition had stopped to be normal and the application of the appropriate assistance)Foe example in some breeds of dog (as Scottish terrier) = the bitch is heavily gravid and the gestational period is normal → 1-2 fetuses have been expelled without exceptional difficulty → from this point, all signs of labor stops and the bitch lies and suckle the young already born (without expelling the greater part of the litter) → no further progress is made, and if treatment is not offered – the fetuses will die → infection of the uterus and toxemia
Treatment In uniparous species→ correction of the dystocia that caused the inertia In multiparous spp→ treatment depends on duration of the parturition, number of still un-born fetuses and their condition and the degree of uterine infection:a. In the early stages delivery of the fetus which causes the dystocia may be followed by return of uterine contractility (after a few hours) parturition may continue (such is often the case in Sow and occasionally in Bitch and Cat)b. If the case is of longer duration where there are still a few un-born, it is best to proceed with the delivery:Sow → be inserting a hand through the vagina – into the uterus Bitch →Forceps delivery (not good if there are still 3-4 fetuses because it can-not reach them and “blind fishing” can result in uterine rupture)Laparotomy (if the case duration is not more than 12 hours since the beginning of the 2nd stage)Hysterectomy = surgical removal of the uterus (if the case lasted longer and the fetuses are dead and putrefied)
88. Dystocia due to abnormalities or injuries of the pelvic bones (R&O – 186, 222; T - 699)Pelvic area = dorso-ventral (widest) and bisiliac (the 2 iliac bone or 2 any corresponding points on it) dimensions (cm2) of the pelvic inlet → can be measured per rectumThe pelvic area is influenced by:1. Immaturity = early parturition – insufficient dilation of the birth canal2. Breed = cross breeding in beef cattle increases pelvic area (very high incidence in Friesian dairy breeds while Jersey are least affected – but also the bull is influencing)3. Fracture = displaced connection after fracture4. Diet = good nutrition and use of growth stimulants in heifer increases pelvic area5. Development = under development of the dam – nutrition, genetic defect, illness, age (the younger the heifer the higher dystocia rate)
6. Disease = exostosis (benign new growth projecting from a bone surface → can be inherited or acquired after a fracture)
89. Dystocia due to abnormal size of the fetus (absolute and relative) (R&O – 186, 222)
Relative oversize – the fetus is of normal dimensions but the maternal pelvis is too small. Absolute oversize – the maternal pelvis is normal but the fetus is abnormally large
1. Small litter2. Breed and cross breeding Calf weightGestation lengthSire effect (individual ♂ show marked effect on birth weight of their progeny)Sex → ♂ birth weight is usually higher than ♀Twining (birth weight )3. Prolonged gestation4. Developmental defects Duplication (hereditary muscle hyper-trophy in Bo)Ascites (abnormal accumulation of fluid)Anasarca (extensive subcutaneous edema = generalized edema)Hydrocephalus
90. Dystocia due to deviation of the head and neck of the fetus (R&O – 253, 257)Lateral deviation of the head – anterior presentation Cow and EweThe head may by displaced to either sideWhen treated in early 2nd stage → easily corrected by hand (without the need for epidural anesthesia) → the hand is lubricated and inserted, and when the straining stops – the fetus is pushed back (from the base of the neck) → then the hand is quickly transferred to the muzzle of the calf – which is firmly grasped and corrected (nose in line with the birth canal – Fig. 14.6)In more inaccessible case, the muzzle may be reached after first traction on the on the commissure of the mouth (Fig. 14.7) or on the mandible (Fig. 14.8) → ropes are now put on the limbs → traction synchronized with cow expulsion effortsIn other cases with greater loss of fetal fluid and with the uterus contracted o the fetus, it is more difficult to correct the posture → epidural anesthesia → substitution of fetal fluids → a rope is applied over the mandible of the calf (Fig. 14.8) and the other end is given to an assistant → the operator inserts his hand again, grasp the muzzle and correct the posture of the head, while the assistant pulls the rope to keep the head in its corrected positionIn very delayed cases of head deviation and in congenital rigid curvature of the neck (wryneck)→ correction is impossible and decapitation is required (wire-saw fetotomy)→ the head is removed first and later the rest of the body
MareMore serious in foal then in calf due to the greater length of the head and neck (Fig 14.11)→ the foals nose lies further away near the femoro-tibial and femoro-carpal joints (instead of in the middle rib) → thus, except in ponies – the displaced head is beyond reach of the vet. hands, and special instruments are required (Kuhn’s crutch, Blanchard’s long flexible hook and Krey-Schottler double hook – all “extend the arm” of the vet. and help to grasp the foal)Kuhn’s crutch (it has a 1 m long handle and a U-shaped end-piece with an eyelet for cord in the end of each arm) → after grasping the head by the crutch and pulling it → the vet. pushes the fetus by manual pressure one the pectoral muscles, while an assistant pulls the head (with the crutch) → this way the foal head may be brought into reach and the muzzle is directed into the birth canal → gentle pulling of the forelegs and headBlanchard’s hook (long handled hook which is designed to engage the foals orbit, commissure of the mouth, nostril or ear-canal) → the instrument is inserted and when the fetal head is felt, an attempt is made → if a firm hold is obtained, the hook is pulled with the head while the fetal trunk is pushed → the head reaches the vet. reachKrey-Schottler double hook (may be used if the foal is dead with laterally displaced head or in difficult dystocia with a living fetus) → the method is to insert and pull again and again as many time as necessary to bring the head within reach (done be applying the hooks more and more forward – to the dorsal skin and muscles of the neck)In case of wryneck, it is impossible to extend the neck → the head and neck must be amputated (wire-saw fetotomy)
Downward displacement of the head – anterior presentationCow and MareUncommon in cattle and usually takes the form of “vertex posture” in which the calf’s nose is stopped by the pelvic brim and the forehead is directed into the pelvis (Fig. 14.9) → provided sufficient pushing can be achieved – correction is very easy, but neglected cases may require epidural anesthesia and fetal fluid supplementMore severe variation, the “nape presentation” and “breast-head” posture (the head is pressed ventrally between the forelimbs) → are usually caused by traction of the limbs – before the head had extended → treated similarly to “vertex posture”, but if its not → one or both of the calf forelimbs should be pushed back into the uterus (gives room for the head to be rotated and lifted over the pelvic brim → then the leg(s) is extended again and the fetus is pulledTying the Cow and placing her in dorsal recumbency may greatly help these manipulations in very difficult casesAnother alternative is to rotate the fetus by means of Cammerer’s torsion fork – applied on the legs → temporary ventral position from which the head may be more easily extendedWhen manipulative correction fails → fetotomy = “nape presentation” the head is removed= “breast-head posture” one forelimb sectionIn difficult cases where the calf is still alive → cesarean section
91. Dystocia due to deviation of the forelimbs (in anterior presentation) (R&O – 250, 256, 260)98. Fetotomy operations in the anterior presentation Not detected in the bitchCarpal flexion postureCow, Mare and EweOne or both feet may be affectedIn unilateral cases, the flexed carpus is located at the pelvic inlet, while the forefoot may be visible at the vulva Push the fetus back (by his head or shoulder) → grasp the retained foot (by hand or rope), push the carpal up and then over the pelvic brim (the fetal foot should always be carried over the pelvic brim in the cupped hand of the vet. as seen in Fig. 14.1-14.3, 14.10)In very prolonged dystocia and cases of ankylosis (abnormal immobility of a joint) → the limb can-not be extended and must be cut at the carpus (wire-saw fetotomy)
Incomplete extension of the elbow(s)Cow, Mare and EweThe digits emerging at the same level as the fetal muzzle (instead of before it)The head is pushed back → each limb is pulled in turn (the leg is pulled in an oblique upper direction so as to lift the processus olecranon over the maternal pelvic brim)→ traction of the forelimbs + head
Shoulder flexion posture = complete retention of the forelimb(s)Cow, Mare and EweMay be unilateral or bilateral (Fig. 14.4-14.5)In bilateral type the head in partially of completely born, but there is no-signs of the feet (in bilateral carpal flexion the head can-not be advanced so far)In a “roomy” cow with small calf → traction in the abnormal posture may helpIf it is not possible to pull the fetus out in this posture (to big) → postural correction is usually easy (unless there has been much delay)If the fetus is dead and the extruding head is swollen (to big to push back) → Krey’s hooks are placed in the orbits and the head is pulled – so as to bring the head beyond the vulva → amputation of the head (at occipito-atlas joint) → following this, the fetus is pushed back and the retained feet tend to come forward → the fetus forearm is grasped and the defect is easily converted to carpal flexion posture and relieved accordingly (Fig. 14.4-14.5)In more difficult cases, the limb must be caught → then the noose pushed back until it lies above the fetlock (metacarpal joint)→ the forefoot are turned to their natural parturition position (as described before)→ the fetus is pulled outIn delayed cases, such manipulation may be impossible → fetotomy of the feet
Foot-nape postureMareUpward (above the head) displacement of one or both forelimbs →unique to Eq – due to a more slender head and longer limbs of the foal (great danger of penetrating the vaginal roof by the feet)The foal head is pushed back, while the uppermost limb is pulled → similar manipulation of the other foot → finally, the head is raised again and each limb is placed underneath → traction of both head and forelimbsIf the limbs penetrated the vaginal roof → epidural anesthesia or deep narcosis→ reposition is attempt, but if it is not possible → amputation (wire-saw) of the head or upper limb (which-ever is easier)If one foot is already protruding through the ruptured perineum or rectum → incision of the perineum may be necessary → extraction of the fetus → repair both the laceration and the incision
93. Dystocia due to deviation of the hind limbs (in posterior presentation) (R&O - 261)99. Fetotomy operations in the posterior presentation101. Bisection of the pelvis in breech presentation
Hock (tarsus) flexion postureCow and MareThe condition is usually bilateral (14.15) → the hock may be felt in front of the pelvic brim or inside the birth canalThe aim of the procedure is to extend the hock joint(s) and the difficulty is in finding sufficient space for this to be done (with or without epidural anesthesia and/or fetal fluid replacement – if needed)In new cases the posture may be corrected by hand → the fetus is pushed back as far as possible → the hand grasps the fetal hock → the points of the digits are cupped in the hand and the foot is lifted over the pelvic brim (the limb extends into the vagina)In cases where it is impossible to extend the hock due to lack of space→ an assistant inserts his arm and press forwards and upwards on the point of the hock, while the vet. tries as before to bring the foot into the pelvic canalAn alternative method is to tie a rope around the hock flexure, and the rope passes out between the digits (Fig. 14.16) → the fetus is pushed and while an assistant pulls the rope → the foot is lifted over the pelvic brimIn cases where it is impossible to extend the hock and usually the calf is dead → 2 alternatives:1. Cutting the Achilles tendon allows maximum flexion of the hock and thus allow the limb to be pulled into the birth canal2. The limb may be amputated below the point of the hock (wire-saw fetotomy)(Fig.-14.17)Mare → the same methods as in cattle, but due to the longer limbs of the foal – the procedure is much more difficult and fetotomy is more often
Hip flexion postureCow, Mare and EweBilateral retention = “breech presentation” → usually on rectal examination, the calf tail is recognized (Fig.-14.18) and the degree of obstruction of the birth canal variesThe aim of the treatment is to convert the condition into a hock joint flexion, and than continue as described before (with or without epidural anesthesia and/or fetal fluid replacement – if needed)If epidural anesthesia is applied, it is possible (but usually not necessary) to suspend the cow by attaching its hind legs to an overhead beam → can be very helpfulThe calf is pushed back (with a view to bring the retained limbs within reach) → the leg is grasped as close to the hock as possible → traction of the limb converts the posture into hock flexion → continue as described beforeIf it is impossible to bring the hock within reach (usually the calf is dead) → fetotomy to remove the retained hind-limb (wire-saw fetotomy) → the femur is sectioned through its articular head → the detached feet is removed, and the other foot is sectioned in the same wayAnother method after the section of one foot → apply traction by an anal hook which is passed into the fetal anus and over the fetal pelvic brim (Fig.-14.19) → attempt to deliver the calf without extending the other footOccasionally, after amputation of one hind limb, it is possible to extend the other limb and deliver the fetus by traction of the extended limbMare → occasionally a mare will foal un-aided despite complete retention of the hind limbs, and in many cases it is possible to deliver breech presentation by traction without correcting the posture (but in recent cases, especially if the fetus is alive, an attempt should be made to extend the limbs – although much more difficulty is expected because of the long limbs of the foal)
92. Dystocia due to pathological position of the fetus (R&O – 266)94. Dystocia due to pathological presentation, position and posture of the fetusPositionMore frequent in horse than in cattle – due to that in late gestation or 1st stage labor (not in cattle) there is physiological rotation of the fetus from ventral to dorsal position, and this mechanism occasionally breaks down → the fetus then presents longitudinally (anterior or posterior) – either with its vertebral column applied to one side of the uterus (right or left lateral position) or facing the floor of the birth canal (ventral position)The process whereby Cow or Ewe fetus sometimes comes to lie in ventral position is not understood (probably rises during 1st stage due to uterus peristaltic forces and relaxation)In order to make birth possible → the fetus must be rotated into normal (dorsal) upright position (pushing the fetus and then rotating it – the mother must be standing + epidural anesthesia)In Ewe we use the same methods as for Mare and Cow – but by raising the Ewe hindquarters and supplementing fetal fluid → rotation is much easier and instruments are rarely required
Anterior presentation, lateral position (Mare, Cow and Ewe)If fetus is alive → vet passes his hand to the fetal head and presses on its eyeballs – which cases convulsive reflex response in the fetus and by applying rotational force in the appropriate direction, it is easy to turn the fetus into dorsal position → the fetal nose and limbs are advanced into the birth canal → pulling with maternal helpIf the live fetus is un-responsive to the presses on its eyeballs → mechanical rotation (with epidural anesthesia) by Cammerer’s torsion fork (U-shaped) and ropes on the head and forefeet → another 2 ropes are passed and encircles the upper-forearm → the fork is passed into the vagina and each tooth is attached to one of the upper-forearm ropes → the vet pushes the fetus with the fork, and at the same time turns it vigorously to the appropriate side → if there is sufficient space and fetal fluids (can be supplemented) – the fetus rotatesKuhn’s crutch can be used instead of Cammerer’s fork
Anterior presentation, ventral position (Mare, Cow and Ewe)Eyeball pressure with manual rotation or mechanical rotation by torsion forkIf the dam is down and will not get up → should be placed in dorsal recumbency → raising the hind quarters can be helpfulIf the fetus rests on its back with the head and limbs flexed on its neck and thorax → fetus is pushed and the head and forelimbs extended → rotation
Posterior presentation, lateral position (Mare, Cow and Ewe)The vet. inserts his hand and grasps the upper part of the limb → simultaneous pushing (down) and rotation – to rotate the fetus in 90 → if its impossible – Cammerer’s torsion fork applied to the hind-limbs
Posterior presentation, ventral position (Mare, Cow and Ewe)The vet. inserts a hand between the fetus hind-limbs – up to the inguinal region, where one of the thighs is grasped → the fetus is pushed and rotated in a half circle → if its not possible - Cammerer’s torsion fork should be used An alternative method is to place a traction bar and tie it by rope to the hind-feet → rotation force is applied to the traction barThere is high risk that the hind-feet of a foal in this position – will penetrate the vagina and rectum → if it did penetrate → cesarean section and later correction of the fistula
PresentationThe vertebral column of the fetus is displaced vertically or transversely to the pelvic inlet (instead of being in line with the birth canal) → since there is limited space in the vertical plane, absolute vertical position is not-possible and oblique vertical presentation is rare (in Mare)Classification is according whether the fetal vertebral column or abdomen is presented at the pelvic inlet Dorso-vertical presentation = the fetal vertebral column is presented at the pelvic inletVentro-ventral presentation = the fetal abdomen is presented at the pelvic inlet = “dog sitting position”
Oblique dorso-vertical presentation (Mare, Cow and Ewe)According whether the head or breech (hindquarters) is nearer to the pelvic inlet, the presentation is converted into anterior or posterior longitudinal = bring the fetal head and/or limbs to the pelvic inlet → convert the defect into ventral longitudinal presentation → then rotate to dorsal position (as described before – pushing and presence of natural or artificial fluid are both essential)The fetus is griped by Krey’s hook as near as possible to the more proximal fetal extremity → then, the fetus is pushed and the hook is pulled – until the fore or hind quarters of the fetus are in the pelvic inlet → adjustment of the position and posture → delivery by traction
Oblique ventro-vertical presentation (Mare, Cow and Ewe) = “dog sitting position” (Fig-15.2)Diagnosed by – protrusion of head and forelimbs (which have been pulled without success) = the head and forefeet are in the vagina and its hind-parts in the uterus (hind-feet are also in the birth canal and the rest on the pelvic brim) → the more the fetus is pulled – the greater the impactionMost cases are severely impacted → epidural anesthesia and adding lubricant fluid into the uterus → pushing the fetus sufficiently to allow the hindquarters to be pushed off the pelvic brim into the uterus (thus converting the dystocia into simple anterior presentation) If it former is not working, the new aim is to push the front of the fetus and to convert to posterior presentation, ventral position → a rope is tied in the upper part of the forelimbs and connected to Kuhn’s crutch or Cammerer’s torsion fork → the fetus if strongly pushed (with the instrument) → as soon as it is possible – ropes are tied to the hind feet → the fetus is pushed again while the hind-feet are held strongly (this way, the fetus might be pushed into the uterus – in posterior presentation, ventral position) → then the fetus is rotated from ventral to dorsal position → traction of the hind-legsIn case that the head, neck and forelimb protrude from the vulva, pushing will-not succeed → mare should be sedated (or better under general anesthesia) and placed in dorsal recumbency → fetotomy (the loop of the weir is placed as far as possible around the fetal thorax) → evisceration → ropes are attached to the hind-feet → the stumped vertebral column is pushed, while the ropes are pulled (the remainder of the trunk is pushed into the uterus) → rotation and traction of the hind-feet (if there is swelling of the vaginal mucosa – which prevents vaginal manipulation and fetotomy cesarean section)
Dorso-transverse presentation (Mare, Cow and Ewe) Fig.-15.3-15.4The vet. should decide which extremity of the fetus is nearer to the pelvic inlet → correction by pushing the fetus and pulling his nearer extremity to the birth canalUnless one extremity is within easy reach – it is very difficult or impossible to reach it in the uterus → if there appears to be a chance of success, the Cow should be given epidural anesthesia and the Mare deep sedation (or better general anesthesia – so she can be placed on her back) → supplement of fetal fluid → attempt is made by manipulation of the proximal fetal extremity to turn the fetus into ventral position, anterior or posterior presentation → rotate the fetus into dorsal position → delivery by traction (if this version can-not be done cesarean section because fetotomy is very difficult to carry out in this type of dystocia)
Ventro-transverse presentation (Mare, Cow and Ewe) Fig.-15.5A variable number of fetal appendages may enter the birth canal (must be distinguished from twins and double monsters and from schistosoma reflexes) → (presence of uterine fluid is essential) epidural anesthesia in Cow or deep sedation (or better general anesthesia – so she can be placed on her back) in Mare → convert the abnormality into longitudinal (usually posterior presentation, ventral position) presentation – by pulling the posterior extremity (with ropes) and pushing the anterior extremity (with Cammerer’s or Kuhn’s crutch and cuffs) → the fetus is rotated from ventral to dorsal position → delivery by traction of the hind-limbs → unless conversion progress is rapid and successful, cesarean section is indicated (fetotomy requires a lot of efforts, dangerous to the dam and un-certain to success)In bi-corneal type (Fig.15.6) of transverse presentation (the fetal extremities are disposed in the 2 horns and its trunk lies across the anterior portion of the uterus body) → if ventral displacement of the uterus had occurred, it may be impossible to palpate the fetus → cesarean section
95. Twining in uniparous animals as a common cause of dystocia (R&O – 272)Mare – abortion is more likely than dystocia (very small uterine capacity)Cow – twins can cause dystociaSheep – it is un-certain that twins predispose to dystocia (dystocia due to twins is balanced by reduced feto-pelvic disproportion)Twin dystocia is of 3 types:1. Both fetuses try to pass the birth canal together (Fig-16.1-16.2)2. One fetus in the birth canal – but with defective posture, position or presentation (usually due to insufficient uterine space)3. Uterine inertia (over-stretching of the uterus by excessive fetal load or premature birth defective uterine contractions birth of the 1st or 2nd fetus does-not proceed although presentation is normal)If the twins are of small body size → manipulative correction and delivery are possibleFirst the dystocia must be diagnosed (as a rule in all cases of difficult birth – the presenting fetal appendages must be identified this way the vet. will-not apply traction to the 2 fetuses at once, nor should the twins be mistaken for schistosomus, double monster or ventro-transverse presentation of a single fetus)Where a twin is presented with an abnormality of posture it is treated as if it were a single fetus (if it is un-known that twins are present – but it is suspected because the fetus is small or because of the history of the dam → the uterus must be searched for another fetus)Simultaneous presentation of twins (type no.1) is treated in logical sequence:The polarity of the fetuses is determined → the more advanced fetus is recognized → its presenting extremity are pulled out (by rope)Any defect of presentation, position or posture – must be diagnosed and treated (epidural anesthesia may help) → the less advanced fetus is pushed, while the nearer one is pulled and delivered → the 2nd fetus posture…is corrected → delivery of the 2nd fetusIt is easier to deliver if the hindquarters are raisedThe uterus should always be examined for another fetus (2nd,3rd…)If correction is impossible → fetotomy of the presenting fetus or cesarean section
96. Dystocia due to fetal monsters (R&O – 273)Mare – monsters are rare except of - Wryneck = torticollisCattle and SheepSchistosomus reflexus = the lateral edges of the somatic disc in the developing embryo curve upwards instead of downwards the viscera float free in the amnion, the head and tail are curved up towards each other the fetus creates dystocia with the free floating viscera or the 4 limbs and the head all together, presenting in birth canalAnkylosis = abnormal immobility and consolidation of a joint (calf legs are bent and fixed in flexion and there is some deformity of the spine)Perosomus elumbus = the vertebral column stops at the caudal thoracic region and the posterior part of the body is joined to the front half be soft tissue onlyDouble monsters = Siam twinsDropsical fetuses = edema = abnormal accumulation of serous fluid in the abdominal cavity or in the cellular tissuesAnasarcous = extensive subcutaneous edemaHydrocephalus = enlargement of the cranium due to abnormal accumulation of CSF within the cerebral ventricular systemPig = Hydrocephalus = see in Cattle and SheepDouble monsters = see in Cattle and SheepPerosomus elumbis = see in Cattle and SheepDelivery of monsters Recognition of the exact disposition of the fetal extremities and an estimate of fetal size may be very difficult → the vet. must decide if traction (with lubrication and protection of the birth canal from irregular objects) can do the jobPrior to traction, the diameter of anasarcous, ascites and hydrocephalus – can be reduced by appropriate manipulation or single incisions with a fetotomy knife If moderate traction does-not succeed → fetotomy (wire-saw) of cesarean section (fetotomy should be first considered – due to price and recovery of the dam, and also in all cases where sufficient reduction of the fetal diameter may be achieved by simple sections thus, fetotomy is indicated in ankylosis, wryneck, perosomus elumbus, anterior duplication and schistosomus)Hydrocephalus whose head is too rigid to reduce by cranial puncture → saw-off by wire or chainIf several fetotomy incisions are required (as in excess fetal size - as in anasarca, extensive duplications, or very irregular presentation) → cesarean sectionOccasionally, the presenting part of the fetus is normal, but the distal part is grossly malformed → parturition is normal until the malformed portion engages the pelvic inlet (the cause is not apparent and may be impossible to know) → for example perosomus elumbus, hydrocephalic fetus in posterior presentation, anterior duplications presented posteriorly → in this cases, heavy but unsuccessful traction has usually been applied before the arrival of the vet.→ this history, together with the normal appearance of the presenting portion – should make suspicious of an abnormality → cesarean section is the easier solutionObstetric management of Schistosomus reflexusFetal viscera may be seen protruding from the vulva (if not, they are soon located by vaginal exam.) → the viscera may be mistaken for those of the mother – and uterine rupture may be suspected (shouldn’t be difficult to differ by careful exam. of the organs and the absence of uterine tear)The viscera must be torn away → the fetal diameter is now compared with that of the birth canal → if it seems favorable to birth → Krey's hooks are fastened to the fetus → reasonable traction with adequate lubrication (the expulsive efforts of the cow are gently aided) → if it doesn’t work – wire-sow fetotomy (at the spinal flexure of the fetus Fig-16.3) or cesarean section → the small parts are with-drown by Krey’s hooks → if it is not possible to with-draw they are cut again – perpendicular (90) to the 1st cut
97. Fetotomy – generalSubcutaneous fetotomy – forelimbs (R&O – 242)1. The leg is tied in the metacarpal region – and the rope is pulled by an assistant → The vet. makes a small incision (with scalpel) into the skin in front of the metacarpal joint → Roberts’s fetotomy knife is inserted into this cut, and longitudinal incision is made (on the front of the forelimb) – from the metacarpus to the scapula2. “Skinning” the limb in situ (Fig-13.4) = separation of the skin from the muscles by hand3. Division of the adductor muscles by Roberts’s knife – with vigorous probing → the muscle mass is separated into several ‘strings’ → each ‘string’ is cut by the knife4. Disarticulate the metacarpal joint – so that the digit is left connected to the detached skin of the metacarpus → then, a rope is attached to the cannon bone (3rd metacarpal of Eq or 3rd and 4th metacarpal of Ru)5. The rope is pulled by 2 assistants (with traction bars) and the denuded forelimb is disconnected by the forcible traction of the 2 assistants, while the vet. pushes the front of the fetus (this way, the muscles attached to the top of the scapula are broken and the limb comes away)In many cases the removal of one forelimb gives sufficient reduction in fetal diameter to allow delivery by traction → if delivery is not-possible, the other foreleg must be amputated the same wayOccasionally, after removal of one or both legs – and despite partial rotation of the fetus, the hindquarters become locked at the pelvic inlet → now the calf should be withdrawn as far as possible, and the protruding part of the trunk is completely cut → fetal abdomen is eviscerated → one of the hind-limbs must be removed – and there are 2 ways to do so (the one chosen depend on the mobility of the retained legs):If it is possible, the posterior part of the calf is pushed and one hind-limb is brought forward with the aid of a rope → removal of he limb by subcutaneous fetotomy (as described)If it is not possible to grasp the limb (after pushing) and bring it forward, the leg is amputated by direct cutting fetotomy knife (as Unsworth’s) → an incision is made over the hip joint of the leg to be removed → the muscles lateral to the femoral head are divided and the upper extremity of the femur is isolated → pulled by a rope, the teres ligament of the femur head is torn and the head is freed from the acetabulum → then, the rope is tied around the trochanter and the leg is pulled out of the skin after one hind-leg is removed, the remaining of the posterior part of the fetus can be withdrawn by traction (by a double hook)
Subcutaneous fetotomy – hind-limbs (R&O – 247)A nick is made just above the metatarsal joint – on the posterior aspect of the extended fetal leg → into this nick is placed the ‘beak’ of Roberts’s knife → an incision is made with the knife up the back of the limb up to the anterior gluteal region → the skin is separated all around the leg → the muscles above the hip joint and the abductor muscles are divided → the femoral head is detached from the acetabulum (by forcible rotating the limb laterally) → the skin is cut around the metatarsal joint → a rope is placed over the freed end of the metatarsus → traction of the rope by 2 assistants while the vet. is pushing the calf → removal of the leg allows traction and expulsion of the whole fetus → if it does-not, the other hind-limb is similarly removedIf after removal of one or both hind-legs – the fore-quarters become obstructed at the pelvic inlet → as much of the calf as possible is pulled out of the vulva and amputated → evisceration → the reminder is pushed back → an incision is made (Unsworth’s knife) in the skin over the scapula cartilage and the muscles which connect the scapula are divided → the upper end of the shoulder is isolated (knife dissection) → Krey’s hooks are connected to the scapula and help to pull out → the remainder of the calf is pulled
Percutaneous fetotomy – forelimbs (R&O – 245)Delivery by wire-saw tubular fetotomyFor ease of sterilization – the model preferred is the Thygesen’s instrumentRemoval of the fetal head, neck and one forelimb (Fig – 13.6) → the wire is looped around the neck and forelimb and pushed back as far as possible (behind the posterior angle of the scapula – where a deep incision is made with Unsworth’s knife to accommodate the wire) → the head of the instrument is brought to the base of the neck – on the opposite side to the foreleg being removed → the wire is pulled in long strokes – so as to move the max. length of available wire → the detached segment is drawn-out of the birth canal → the remainder is delivered by tractionIf birth is not possible (after cutting the head and one forearm) → the calf is pushed back and the wire is put around the trunk of the calf (Fig-13.7) → the vertebral column is cut --. The anterior part of the calf is delivered → the remainder of the abdomen is eviscerated → cut the hind extremity in a sagital plane (the wire is passed around the sacrum and behind the perineum and the head of the instrument is placed against the fetal spine Fig-13.8) → the hindquarters are divided and each half can be pulled out in turn (by double hook)
Percutaneous fetotomy – hind-limbs (R&O – 248)The wire-loop is placed over one foot and passed up the limb – until it lies anterior to the external angle of the ileum (where a cut in the skin is done by Unsworth’s knife)→ the head of the instrument is placed lateral to the anus, and the tail of the calf must be introduced into the loop (otherwise the wire will slip during sawing – and the section will be made through the distal 1/3 instead of the upper extremity of the femur) → the cut limb is removed → the rest of the body is pulled by Krey-Schottler hook (attached to the perineum) or with the aid of Obermayer’s anal hook (passed over the calf’s pubic brim) → if delivery is still impossible, the other hind-limb must be removedIf the calf can-not be removed after removal of both feet → the trunk is cut (wire loop) as far as possible → then one or if necessary both forelimbs are amputated (the wire is passed with the aid of Schriever’s introducer) → the cut limb may be pulled out by Krey’s hook → the anterior portion of the calf is pulled out → if its not possible, the other forelimb must be cut in the same manner
102. aftercare and examination of the dam after fetotomy ( J 171 )
the vagina and uterus of the dam should be manually examined after fetotomy for evidence of soft-tissue damage. Local and parenteral antibiotics should be administered. If the placenta is readily detachable from the uterine caruncles it should be removed. Careful nursing for a few days s indicated.
1. Examination for the presence of another fetuses in the uterus and abdominal cavity → careful palpation or ultrasound2. The genital canal and uterus should be examined for the presence of an invaginated uterine horn, laceration, ruptures. * small, superficial tears of the cervix, vagina or vulva → nor important unless there is retained placenta. * in the vulvo-vaginal border, laceration may lead to infection and necrosis → local treatment with healing protective ointments + antibiotic * extensive laceration of the cervix → may lead to cervical induration and chronic cervicitis any teat or rupture of the uterus → poor prognosis → slaughter, laparotomy, hysterectomy. * large tear in vulva, vagina, cervix or uterus → suture ( puling the cervix and uterus back or outside the vulva make the suture easier. * small uterine rupture (mainly in dorsal wall) → may heal spontaneously, and the uterus should be stimulated to contract by oxytocin . 3. examination of placenta + placentome ( cow + mare) → avoid retained placenta.4. uterine infection → antibiotic, local treatment of uterus with antiseptics, oxytocin (stimulate uterine involution + prevent sepsis), removal of any placenta present. 5. prevent possible uterus prolapse after forced extraction → oxytocin (prevent prolapse by aiding involution + separate fetal membrane from uterus)6. animal unable to rise → examination for paresis, hip-dislocation, spinal injury, pelvic injury. 7. examination of udder for any wounds / laceration that occur during the dystocia.
104. Laparohysterotomi (cesarean section) in the sow (R&O 329)
indication – irreducible vaginal prolapse, fetal emphysema, secondary uterine inertia. Preparturient vaginal prolapse may be complicated by rectal prolapse and even the gravid uterus and often undergoes marked edematous swellingin secondary inertia, it is not always easy to be certain that fetuses remain in the uterus (→ X ray)
Anesthesia The operation is usually performed under deep sedation and local analgesia, or general anesthesia.
Operative techniqueThe operation is performed through a vertical flank incision on either side. The gravid horn should be exteriorized for incision outside the peritoneal cavity in order to minimize peritoneal contamination. If the fetuses are not emphysematous, it is possible to evacuate both horns through a single incision as close to the uterine body as possible. The piglets in the ovarian poles of the cornua are squeezed down then horn and grasped through the incision. If the fetuses are emphysematous multiple incision sited directly over or between them may be necessary. Placenta which have not separated should be left inside and not forcibly removed by traction. because the cornua is long it is important to be sure that all the piglets have been removed. The uterine incision is repaired with inversion sutures.
Maternal recovery and causes of deathDeaths are usually due to the combined effect of toxemia and surgical shock and occur during the immediate postoperative period. Animals which are in high risk to die can be identified according to cyanosis of the limbs, ears and udder. Sever preoperative vaginal prolapse may recur after surgery and require the insertion of a temporary retaining perivaginal suture.
105. Laparohysterotomi (cesarean section) in the bitch and queen (T 819, R&O 332)
bitch
IndicationThe decision to operate is based largely on a subjective assessment of the circumstances of the case * the duration and prognosis of the whelping, * the number and viability of fetuses born and unborn * the nature of vaginal discharge * changes in the pattern of straining * uninformative information on vaginal examination * delay in the initiation of parturition * delay in propulsion * delay in delivery despite vigorous straining in any case of delay in parturition, the border between decision to operate, or manipulate by other ways, depends on the case and experience of the vet. In some brachycephalic breeds, pregnancy is routinely terminate by cesarean section, largely on the high incidence of dystocia and stillbirth. Whatever the reason, surgery should normally be delayed until the onset of first stage labor in order to avoid the risk of fetal pregnancy.
AnesthesiaThe choice for anesthetic technique is important to ensure fetal viability or because of the condition of the bitch after a protracted or complicated whelping. Fetal viability can be confirmed preoperatively, but the absent of positive signs does not necessarily mean that all the fetuses are dead. The delivery of live fetuses depends on correcting or preventing fetal depression and hypoxia which may be due to: * placental separation* Maternal hypotension (over dose)* inadequate pulmonary ventilation of the bitch during anesthesia
Operative techniqueThe operation is performed either through a flank or a midline laparotomy. The linea alba is ideal approach to the gravid uterus. Vein between the rows of mammary gland immediately below the skin have to be ligated the incision may be extended cranially as far as necessary, and there is access to both uterine horns. The wall of the gravid uterus is thin and stretched and tears easily in a circumferantial manner around the horns or body. If the uterus can be exteriorized, al the fetuses should be removed through a single, longitudinal incision on the dorsal surface of the uterine body. Those in the upper segment of the cornua are milked through the uterine wall until their membranes rupture and the fetal extremities, can be grasped with fingers through the hysterotomy incision. If the placenta slips out with the fetus, it is likely that the puppy is dead, but immediate palpation is still indicated for evidence of heart beat. Fetuses bathed in dark-green fluid are usually dead. After exteriorization of the uterus, the peritoneal cavity is packed with swabs to prevent subsequent contamination with uterine fluid. The uterine incision is closed with two rows of interrupted or continuous inversion sutures. The peritoneal and muscle layers of the laparotomy wound are repaired with interrupted stitches and the subcutaneous dead space is obliterated with a row of absorbable sutures. the skin sutures should be loosely but securely tied. The immediate administration of oxytocin induces uterine involution and expulsion of remaining placenta and uterine debris
Postoperative period
* a continuing vaginal discharge of blood after cesarean section may indicate serious hemorrhage from areas of placental attachment if placentas have been forcibly detached. This a life-threatening complication and indicate the need for further oxytocin therapy immediately.
Queenindicationcesarean section should be considered in the following situation:* in a 70 – day pregnancy when medical induction has not been possible * in unresponsive primary or secondary uterine inertia * irreducible obstructive dystocia* when kittens are valuable and it is believed that other manipulation may damage kittens or the dam’s genital system (especially if two or more fetuses are retained) * when a heavy discharge is present and uterine infection is suspected* a female with a history of recurrent cesarean section. * surgery should be considered in females with elevated or subnormal temperatures, since operation may be less stressful than prolonged labor
106. Laparohysterotomy (cesarean section) in the ewe and doe (R&O 330, T 892, 592 )
EWEIndicationThe main indication for cesarean section in the ewe are failure of the cervix to dilate, irreducible or severely traumatized vaginal prolapse, fetopelvic disproportion and fatal emphysema after protracted dystocia. Vaginal prolapse should be initially be treated conservatively by reposition and the insertion of vulval retention sutures, in the hope that pregnancy will continue to term. Operative techniqueHysterotomy is performed through a left flank incision under paravertebral nerve block or local infiltration analgesia with the animal in the right lateral recumbency.
AnesthesiaCare is essential in inducing local analgesia in sheep because accidental intravenous administration or the injection of an excessive quantity of anesthetic agent may rapidly result in convulsion. All general anesthetic technique incur some risk of regurgitation and many depress the fetus
Operative techniqueThe viability, position and number of lambs present at the time of surgery should be considered when selecting the site for the abdominal incision.The most used approach is through the left flank, although the midline, paramedian, right and left dorsoventral abdominal incision can be used. An incision of 15 cm is made through the abdominal wall and into the peritoneal cavity. the most accessible extremity or the head of the lamb then palpated within the uterus and gently manipulated through the incision. The uterine wall is incised through a relatively a vascular region, avoiding any cotyledons. The incision should be made over a sufficient length to enable easy manipulation and rapid delivery of the lamb. Prolonged manipulation of the lamb in uterus may stimulate the lamb to breath amniotic fluid, which is often contaminated with meconium. The sheep is highly susceptible to the toxemic effect of intrauterine clostridial infection, and most deaths are due to this complication.
GOATIndicationCesarean section is made to relieve dystocia, to obtain caprine arthritis-encephalitis (CAE0-free kids.The doe should be careful physical evaluated before the surgery. If signs of shock (hypovolemic and cardiovascular collapse) are evident, I.V therapy should be given.
AnesthesiaIf the doe is profoundly depressed, she may require only leg restrain and local anesthesia at the incision site (30 ml lidocaine). The regional therapy of choice is epidural analgesia at the lumbosacral junction.
Surgical procedureThe left paralumbar fossa is clipped, prepared, and draped for aseptic surgery. A 15-cm incision, centered in the left paralumbar fossa, is made beginning approximately 4 cm ventral to the lumbar transverse processes. The skin, external abdominal oblique, internal abdominal oblique and transverse muscles of abdomen and peritoneum are incised or split separately. The gravid uterus is located and gently delivered to the incision. It is often possible to completely exteriorize the gravid horn. The uterus is incised along the greater curvature, preferably between rows of placentomes. This incision should be of sufficient length to avoid tearing the uterus. The fetal membranes are incised, and the fetus is extracted. Contamination of the abdomen with uterine fluids should be prevented. The umbilical cord is stretched and broken near the body wall. Excessive hemorrhage can
be controlled with a simple ligature. The uterus should be evaluated closely for additional kids. These may be delivered through the original incision or, if necessary, a second incision may be made along the greater curvature of the other uterine horn. The uterus is closed after the practitioner has assured that there are no additional kids. The placenta may be partiallyresected to facilitate uterine closure. If the fetus is dead or emphysematous or if there is evidence ofmetritis, antibiotic or antiseptic boluses may be placed in the uterus. The uterus is copiously lavaged with sterile saline and is returned to the abdomen. It is palpated to ensure that it is in normal position. following surgery, the doe may be given 5 units of oxytocin intravenously or intramuscularly to aid in involution of the uterus. Within 24 to 48 hours the cervix will usually dilate and the placenta will be passed.
PrognosisThe prognosis after cesarean section is good if the surgery was preformed electively. A guarded prognosis for life and fertility should be given if the fetus was emphysematous or macerated or if the doe was seriously ill prior to the operation
107. choice of anesthetic procedure according to surgical approach (Laparohysterectomy) (T 351, J 153)
usually epidural anesthesia and regional or local anesthesia are sufficient for most patients. General anesthesia and deep sedation should be avoided when the fetus is alive. Xylazine can be used, but it has disadvantage by adversely increasing myometrial tone. A muscle relaxant drug, isosuprine, is used to simplify manipulation of the uterus at the laparotomy incision. Oxytocin is used after surgery to neutralize the action of relaxant.
Flank operation – standing animal – epidural injection of 5 – 10 ml 2% solution procaine hydrochloride will reduce abdominal straining, defecation and tail movement and preserve the standing position. Linear infiltration of the dorsal and cranial boundaries of the operative field with 2% procaine hydrochloride provides satisfactory anesthesia.
Ventral midline approach – low epidural anesthesia aids in preventing abdominal straining during the procedure. The ventral surface of the abdomen is shaved. The midline is infiltrated with 2% procaine hydrochloride from 7 cm anterior to the umbilicus to the base of the udder.
EweLocal anesthesia is normally used and may be given by local infiltration, inverted L block or paravertebral method. 60 ml of 2% lignocaine is required for the local infiltration. Epidural anesthesia is useful to prevent straining during surgery and 2 – 4 ml of 2% lignocaine is injected using the space between the first and second coccygeal vertebrae.
Dogs and cats – although local and epidural anesthesia can be used for cesarean section, general anesthesia is more satisfactory. Almost all anesthetic and sedative agents will cross the placenta and have some adverse effect upon the fetus. Gaseous anesthetics are rapidly excreted via the respiratory system in both kittens and puppies and are the safest anesthetic agents for cesarean section. Masking down with halothane followed by intubation and maintenance with halothane and oxygen produces satisfactory anesthesia. A good supply of oxygen at all times, including the pre-induction period, is very important to ensure a good supply of this vital gas to the young. Halothane may reduce the activity of uterine muscle and postoperative administration of oxytocin to encourage uterine involution is advisable. A good supply of oxygen must be maintained throughout surgery to ensure that fetal life is not compromised. Recovery from general anesthesia must be monitored. Vomiting may occur in the recovery phase (as it may during induction) if the stomach was full at the time of surgery. Preoperative starving is seldom possible in emergency cesarean section cases.
108. ventral midline approach in the cow (T 352)
when cesarean section is done in young beef heifer, the ventral midline approach is better. This site is also useful when the operator encounters a large, greatly distended, septic uterus. low epidural anesthesia aids in preventing abdominal straining during the procedure. The patient in cast and restrained at an angle between right lateral and dorsal recumbency by tying the head and forelimb anteriorly and the left hindlimb posteriorly. The right hindlimb is secured dorsally.The ventral surface of the abdomen is clipped or shaved and scrubbed from the udder to a transverse line 12 cm anterior to the umbilicus. the midline is infiltrated. A sufficient size sheet is put to cover the abdomen, udder and hindlimb.The skin incision is begun 5 – 7 cm anterior to the umbilicus and is carried posteriorly as needed. following incision of the subcutaneous fascia, the abdominal tunic and peritoneum are incised longitudinally. Upon opening the abdominal cavity, the free edge of the greater omentum is identified internal and posterior to the posterior commissure of the abdominal incision. This free edge is drawn anteriorly, thus exposing the uterus. The gravid horn is exteriorized by grasping a fetal part, usually one or both pelvic limb. Incision of the uterus, removal of the fetus and suturing of the uterine incision are performed as usual. Following return of the uterus to the abdominal cavity, the greater omentum is drawn posteriorly over the exposed viscera. The peritoneum and abdominal tunic are closed together, using a continuous overlapping mattress suture. The skin and fascia are sutured with a continuous pattern.
109. Hysterectomy in the bitch and queen ( S 1303 )
indicationelective sterilization is the most common indication for ovariohystrectomy. Removal of the ovaries and the uterus is the usual treatment for many of the ovarian and uterine disease ( ovarian cyst, pyometra, uterine torsion). Ovariohysterectomy is also indicated to prevent recurrence of vaginal hyperplasia. The average age for spaying of cat and dogs is around 6 month, either just before or after their first estrus.
ProcedureThe length of the midline abdominal incision is based on the size of the animal and whether it is a dog or a cat. The distance between the umbilicus and the pubis is divided into thirds. In the dog, the incision is made in the cranial third because the ovary are more difficult to exteriorize than the uterine body. In the cat, the incision is made in the middle third because the uterine body is more difficult to exteriorize than the ovaries. If the uterus is distended or enlarged, the incision is lengthened. A flank incision is not performed because the entire uterine body is difficult to remove. The right uterine horn is located by means of an ovariohysterectomy hook or the index finger. A clamp is made on the proper ligament of the ovary and is used to retract the ovary while the suspensory ligament is stretched or broken with the index finger. A window is made in the mesovarium caudal to the ovarian vessels the ovarian pedicle is triple clamped, and the pedicle is severed between the clamp closet to the ovary and the middle clamp. The clamp most distant from the ovary is removed so that the pedicle ligature can be placed in its groove.Absorbable suture material is used for ligatures. The pedicle is grasped with small hemostats, the remaining clamp is removed, and the pedicle is inspected for bleeding. The pedicle is gently replaced into the abdomen, and the hemostats is released. The procedure is repeated on the opposite ovarian pedicle. In young dogs or cats two clamps can be used because it is not necessary to groove the pedicle. The broad ligament is severed or torn. If the broad ligament is vascular, it is ligated with one or two sutures before it is cut. Three clamps are placed on the uterine body just cranial to the cervix. The uterine body is severed between the proximal and middle clamps. The uterine arteries are individually ligated caudal to the most caudal clamp. The caudal clamp is removed and the uterus is ligated in the groove that remains. The uterine pedicle is grasped with a small hemostat above the clamp, the clamp is removed, and the pedicle is inspected for bleeding. The pedicle is gently replaced into the abdomen, and the hemostat is removed.
110. Hysterotomy, hysterectomy, hysteropexy, episiotomyHysterotomyIncision of the uterus (cesarean section) → See question no. 104-108
HysterectomySurgical removal of the uterus → See question no. 109
HysteropexyFixation of a displaced uterus by surgery → See question no. 82-84
Episiotomy (T – 341)Surgical incision into the perineum and vagina for obstetrical purpose (the basic assumption is that surgical incision is preferable than tearing, trauma or laceration)Indications =Mutation deliveryOversized fetus deliveryInsufficient dilation of the vulva (hypoplasia or juvenility)Induration of the vulva or vestibule (due to previous trauma)Congenital vulval stenosis (episiotomy can be performed to enlarge the stricture permanently – to void difficult matting and dystocia)In the case of decomposing fetus, partial fetotomy is preferable to episiotomy due to the great contaminationTechnique = 1. Anesthesia is not required for incision (the stretched tissues are insensitive to pain), but it may be required for suture after deliveryEpidural → slow onset (mainly if animal is recumbent) and it may inhibit the desired abdominal pressing once delivery starts againLocal infiltration → ineffective and unnecessary if the limiting fetal part is stretching the vulva2. The incision (scalpel or scissors) begins at a point along the free edge of the stretched vulva, 3-5 cm from the dorsal commisure (the vulva tearing tends to begin at the dorsal commisure and to extend dorsally into the anus and rectum) → the whole vulval lip is cut and the incision continues in dorso-lateral direction (the length of the incision depends on the need for enlargement of the orifice, and usually 7 cm are sufficient to allow delivery without tearing)3. Delivery4. The incision is cleaned5. Suture (absorbable or non-absorbable) with a modified vertical mattress suture (the deep part of suture passes through the skin, fibrous tissue and vestibular submucosa, while the superficial part passes through the skin alone)6. Aftercare include antibiotics and examination of the patient before next breeding season
111. trauma to the birth canal (R&O 278)any part of the birth canal may suffer contusion during forcible extraction of an oversized fetus, but the cervix and vulva are likely to be lacerated than the dilatable vagina. The considerable fat content of the vagina of heifers of the beef breeds makes such animals particularly prone to vaginal contusion when the fetus is oversized. Infection by fusiformis necrophorus is then probable, and a most severe vaginitis ensues. The condition is very painful and cause continuous marked toxemia.
pyogenic infection is also possible. All vaginal contusions and laceration should be treated with antibiotic preparation. Parenteral antibiotics should also be given. Epidural anesthesia gives temporary relief from straining. Rupture of the vagina should be repaired, , if possible, by suturing. Infection following rupture may give rise to peritonitis, with marked toxemia or abscess formation with subsequent vaginal constriction. All vaginal injuries should be treated with attention to the possible sequelae. Wounds of the perineum and vulva are easily sutured. If laceration of the vulva and perineum are left unsutured, scar tissue formation and distortion impeded the sphincter action of the vulva, with consequent aspiration of air, vaginitis and metritis. Than, much more difficult operation is required. When the vulva is incised during parturition of a foal, the incised tissue should be resutured immediately after delivery. Repair of the vulva, perineum and cervix may be done under epidural anesthesia.
112. trauma to the urinary bladder and intestines during parturition ( J 180)
Eversion of the bladderEversion is seen in the mare where the short wide urethra predisposes to the condition in the Post-parturient period.
Clinical signs
The everted organ lies within the vagina or protrudes from the vulva. Examination reveal that the inner surface of the bladder is exposed; the trigonum vesice is seen, with urine coming from the ureter.
TreatmentAfter gentle cleaning the bladder is manually replaced under epidural anesthesia by pushing it back down through the urethra.
Herniation of the bladderThe bladder passes through a tear in the vaginal floor and its serosal surface appears at the vulva → the peritoneal surface of the bladder is visible. It may occur in all species.
Clinical signsA fluid-filed viscus appears at the vulva. In the cow, it might be mistaken for a portion of fluid-filed amnion. In many cases obstruction of the urethra occurs as a result of the displacement of the bladder, which fills with urine.
TreatmentThe bladder is emptied by catheterization or cystocentesis. With the animal under epidural anesthesia the bladder is replaced in its correct position and the torn vaginal floor is repaired. Foley catheter may be left in place for 48 h to prevent filling of the bladder.
Intestinal injuryIt is uncommon but lesion can be seen in cattle slaughtered after parturition. Signs are seldom seen in living animals unless severe intestinal damage has been sustained.
EtiologyLoops of small or large intestine are trapped and squashed between the fetus and the pelvis, especially in cases where dystocia is prolonged, fetal fluids are lost and excessive traction by manipulator has been used.
Clinical signsMinor damage will pass unnoticed. If rupture of the bladder has occurred the signs of developing peritonitis will be seen. Within few hours anorexia, pain intestinal ileus and pyrexia are seen. A full clinical examination is essential and the presence of peritonitis and its extent is established by rectal examination.
TreatmentIntensive antibiotic and supportive therapy (fluid and Non Steroid Anti Inflammatory Drug ) is used. Intraperitoneal antibiotic therapy may also be given. Laparotomy in normally not indicated unless the exact location of the primary injury is known.
113. inversio and prolapsus uteri (R&O 302)
prolapse of the uterus is a common complication of the third stage of labor in the cow and the ewe. it occurs less frequently in the sow and is rare in the mare and bitch. In the ruminant species the prolapse is generally a complete inversion of the gravid cornu, while in the sow and the bitch inversion is generally partial and comprises one cornu only. Cases are on record in which the bitch
has everted one cornu before she has completely delivered the fetuses from the other. In the mare the rare cases of prolapse are generally partial only.
CowMultigravida (of the dairy breeds) are more often involved than heifers. In the majority of instances the prolapse occurs within a few hours of an otherwise normal second-stage labor, although in some it may be delayed several days.
EtiologyThe cause of prolapse of the uterus is not clear, but it occurs during the third stage of labor, within a few hours of the expulsion of the calf, and at a time when some of the fetal cotyledons have separated from the maternal caruncles. The only force that can lift the heavy uterus out of the abdomen into the pelvis and hence propel it to the exterior is abdominal straining. Straining occurs normally during the third stage and is synchronous with the continuing peristaltic contraction of the uterus which occur ever 4 minutes. Uterine inversion and prolapse are associated with the onset of uterine inertia during the third stage when a portion of detached afterbirth occupies the birth canal and protrudes from the vulva. The association with inertia correspond with the greater frequency of prolapse in cows than heifers, in dairy rather than beef cows. it was found that the pregnant horn does not undergo a progressive inversion from its anterior extremity; only the posterior two-third inverts. The affected cow is recumbent, and if in lateral recumbency ruminal tympany will be prominent, but occasionally the cow is standing with everted organ hanging down almost to its hocks.
PrognosisThe prognosis depend on:* type of case* duration of the condition before the treatment * whether the organ has sustained severe injury
replacement of the organ does not offer insurmountable difficulties and recurrence after replacement is uncommon. Such animals conceive again. Occasionally prolapse of the uterus is followed by death of the animal.
TreatmentThe prolapsed viscus should be wrap in a large towel to prevent further contamination. Ruminal tympany should be relieved, if present, by passing stomach tubeAn epidural anesthesia should be given. This will prevent straining, and also has the advantage that defecation is in abeyance during the operation. The everted organ should be washed with warm saline solution. If the fatal membranes are already partially detached and their complete removal can be carried out easily and without injury to the caruncles, this should be done. When attachment is complete or when attempts at detachment are associated with hemorrhage, it is better that the organ be replaced with the membrane still adherent. The prolapsed organ should be palpated in order to detect the possible presence within it of a distended urinary bladder → it should be relieved by the use of a catheter. The operator should replace the uterus, starting with those portions nearest the vulval lips. By gentle pressure, the nearest cotyledons are pushed into the vagina, taking care that the lips of the vulva remain well apart and do not become turned inward. it is better to replace portions of the upper and lower surfaces alternately. As the mass disappears through the lips of the vulva the operator should continue to press it forward to the full length of the arm. The uterus should be pressed forward beyond the cervical ring.To help restore uterine tone, and prevent recurrence of the prolapse, a postoperative injection of oxytocin should be given.
A final advantage of apidural anesthesia is that for an hour after replacement of the organ ant tendency to strain will be removed.
EWEThe operation is very similar to the cow, but it is easier. Epidural anesthesia is not required but it prevent straining after the organ is replaced. The fatal cotyledons cannot readily be detached and it is preferable to leave them attached and return them with the uterus.
114. Atonia uteri post partum ( T 242)uterine atony without any form of disturbance of the detachment process can be a cause of retained placenta. The fetal membrane are already detached and cannot be expelled because of the absence of uterine contraction, or the mechanical process of detachment is hindered by the insufficiency of the uterine contraction and muscle tone. In this case, it is possible to remove the cotyledons from the caruncles without causing any harm by pulling slightly on the fetal membrane.
Ca deficiencyExhaustion (long parturition) – (secondary) ↓low / no – activity of uterus after parturition ↓ retained placenta ↓infection, edema, fluid accumulation.
Primary = Ca deficiencyOver – stretching (twins)Toxic degeneration in bacterial infectionHormone deficiency (estrogen / progesterone, oxytocinHereditary weakness of myometriumSystemic illnessDietary deficiencyFatty infiltration Pre-mature birth / late abortionVery small litter (fail to supply adequate endocrine contribution)Torsion / tear uterus → myometrial contraction ↓125. Paresis puerperalis (M 739) parturient paresis is an febrile disease of mature dairy cows that occurs at or soon after parturition and is manifested by changes in mentation, generalized paresis and circulatory collapse.
Etiology
At or near the time of parturition, the onset of lactation result in the sudden loss of calcium through milk. Serum calcium levels decline from a normal of 10 – 12 mg / dL → 2 – 7 mg / dL. Commonly, serum magnesium is increased, and the cows are hyperglycemic. The disease may occur in cows at any age but is most common in high producing dairy cows above 5 years.
Clinical signs and diagnosisParturient paresis usually occur within 72 h of parturition. The disease can contribute to dystocia, uterine prolapse and retained fatal membrane. There are 3 stages of parturient paresis:* during stage one, cows are able to stand but show signs of hypersensitivity and excitability. Cows may be slightly ataxic, have fine tremors over the flank. Cows may appear restless huffing their rear feet and bellowing. * in stage two, cows are unable to stand but can maintain sternal recumbency. Depression, anorexia, subnormal body temperature and cold extremities are seen. Smooth muscle paralysis leads to GI stasis, which can be manifested as bloat, failure to defecate, and loss of anal sphincter tone. * in stage 3, cows lose consciousness progressively to the point of coma. They are unable to maintain sternal recumbency, have complete muscle flaccidity and can suffer severe bloat. As cardiac output worsens, heart rate can approach 120 beats / min, and pulse may be undetectable. Cows in stage 3 may survive only few hours.
TreatmentTreatment is directed toward restoring the serum calcium level to normal as soon as possible to avoid muscular and nervous damage and recumbency. Recommended treatment is I.V injection of calcium gluconate salt. A general dose is 1 g calcium / 45 kg body W. in heavily lactating cows, a second dose is given SC because it provide a prolonged release of calcium into the circulation. Calcium is cardiotoxic; therefore calcium containing solutions should be administrated slowly, while cardiac auscultation is performedIn mild cases, administration of oral calcium is preferred, because it avoids the risk of cardiotoxic side effects.
Parturient paresis is ewes
Parturient paresis in pregnant ad lactating ewes is a disturbance of metabolism characterized by acute hypocalcemia and rapid development of hyperexcitability, ataxia, paresis, coma, and death.
EtiologyThe exact cause is unknown. Deficiency of calcium or magnesium, or both, may be contributing factors. The disease occurs t any time from 6 weeks before lambing to 10 weeks after, principally in highly conditioned older ewes at pasture.
Clinical signs an diagnosischaracteristically, the disease occurs in outbreaks. The incidence in severe outbreaks can be 30 % at one time. The earliest signs are slight hyperexcitability, muscle tremors and a stilted gait. These are soon followed by dullness, sternal decubitus, mild ruminal tympany and regurgitation of food through the nostrils, coma and death within 6 – 36 h. diagnosis is based on the history and clinical signs. In outbreaks occurring before lambing, pregnancy toxemia is the main differential diagnosis. Diagnosis of hypocalcemia can be confirmed by a dramatic and usually lasting response to calcium therapy.
Treatment
Consist of I.V or SC calcium, preferably with some added magnesium. Affected sheep should be handled with care, lest sudden death occur from heart failure.
126. Eclampcia puerperalis (M 733, 745 )
MareHypocalcemia (Eclampsia) is a rare condition associated with acute depletion of serum ionized calcium. EtiologyProlonged stress and excess calcium losses in milk may result in clinical signs of hypocalcemia. In lactating mares, high milk production and grazing of lush pastures appear to be a predisposing factors. Hypocalcemia after prolonged physical activity results from sweat loss of calcium, increased calcium binding during hypochloremic alkalosis, and stress induced high corticosteroids level. corticosteroids inhibit vitamin D activity, which leads to decreased intestinal absorption and skeletal mobilization off calcium.
Clinical signs The severity of clinical signs corresponds with the serum concentration of ionized calcium. Increased excitability may be the only sign in mild cases. Severely affected horses may show behavioral changes (increased muscle tone, prolapse of the third eyelid, stiffness of gait or hindlimb ataxia, dysphagia, salivation, coma and death). In lactating mares, the disease may take a progressive and sometimes fatal course over 24 – 48 h.
DiagnosisDiagnosis is based on clinical signs, history, and response to treatment. definitive diagnosis requires demonstration of low serum level of ionized calcium.
Treatment
I.V administration of calcium solutions (20% calcium borogluconate), usually result in full recovery. These solution should be given slowly and the cardiovascular response should be closely monitored. If the horse is not improving after the initial infusion, a second dose may be given after 30 minutes. Some horses require repeated treatments over several days.
BitchPuerperal hypocalcemia is an acute, life threatening condition that usually occurs 2 – 4 weeks after whelping. Small bitches with large litters are most often affected.
EtiologyHypocalcemia result from the loss of calcium into the milk and from inadequate dietary calcium intake. This imbalance in calcium metabolism occurs because calcium mobilization from bone into the serum pool is insufficient to maintain the efflux of calcium leaving through the mammary gland. heavy lactational demand from large neonates or a large litter are often noted. Hypocalcemia can occur in any breed of dogs, with any size litter, and at any time during lactation. (rarely) it may occur during early lactation in queens. In dogs, Hypocalcemia has an excitatory effect on nerve and muscle cells. Excitation-secretion coupling is maintained at the neuromuscular junction in dogs with hypocalcemia. Tetany occurs as a result of spontaneous repetitive firing of motor nerve fibers. As a result of the loss of stabilizing membrane-bound calcium, nerve membranes become more permeable to ions and require a stimulus of lesser magnitude to depolarize.
Clinical signsPanting and restlessness are early clinical signs. Tremor, tetany, muscle spasm and gait changes result from increased neuromuscular excitability. Hypothermia may occur is severe cases. Behavioral changes (aggression, salivation, hypersensitivity to stimuli and disorientation) are frequent. Tachycardia, hyperthermia, PU, PD and vomiting are sometime seen.
DiagnosisDiagnosis is made from the history, clinical signs and response to treatment. a pretreatment serum calcium concentration (<7 mg / dL ) usually confirm the diagnosis. A serum chemistry profile is useful to rule out concurrent hypoglycemia and other electrolyte imbalances.
TreatmentSlow I.V Administration of 10 % calcium gluconate. This usually result in rapid clinical improvement within 15 min. muscle relaxation should be immediate. During administration of calcium, heart rate should be monitored for bradycardia or arrhythmia. Once the animal is stable, the dose of calcium gluconate is reduced to saline (0.9 % ) and given S.C. The bitch may remain nonresponsive after correction of hypocalcemia if cerebral edema has developed. Vitamin D supplementation is used if serum calcium concentration remain low.
127. ketosis as a cause of reproductive dysfunction during post partum period ( M 736 )
ketosis is a metabolic disease, characterized by weight loss, decreased milk production and neurologic abnormalities that occur usually during the first 6 weeks of lactation. Predisposing and
concomitant conditions are retained fatal membrane, metritis, mastitis and displaced abomasum. After a cow develops the condition once, she is more likely to b affected during succeeding lactation.
EtiologyKetosis is a result of a negative energy balance in the 6 weeks after parturition. The cow is unable to eat enough nutrients to meet her energy needs for maintenance and milk production during this period. Therefore, blood glucose level drop and hypoglycemia develop. In an effort to correct this condition, body fat and limited protein stores are mobilized for gluconeogenesis. Ketone bodies are produced during the mobilization process.
Clinical signsOnset of signs are usually gradual. Initial signs include a slight decrease in food intake, drop in milk production and firm mucus-covered stools. As the disease progresses, a marked weight loss occurs, movement is limited. There may be an acetone odor to the breath, urine, or milk. Walking may be abnormal with circling and falling. If ketosis is untreated, milk production decrease to a level that does not require much energy to produce.
DiagnosisIt is extremely important to obtain a complete history when ketosis is suspected. Special attention should be given to length of dry period, parturition date, nutrition since parturition and daily milk production records. Rapid loss of body weight, depression and decreased appetite suspect ketosis. All cows suspected of having ketosis should receive physical examination along with special test for ketone body. (Rothera’s test) Blood glucose levels are also helpful. Normal levels of 40 – 60 mg / dL drop to below 25 mg / dL in clinical ketosis
TreatmentRoutine treatment I I.V administration of 500 ml of 50% glucose and I.M administration of glucocorticoid.Glucose administration results in an increase in blood glucose and improve in clinical signs and milk production. However, the recovery is usually transitory, and both clinical signs and milk production soon return to pretreatment level unless glucose treatment is repeated in 24 – 48 h. To effect a rapid and lasting recovery, any predisposing conditions must also be eliminated, and proper nutrition provided.
128. mania puerperalis (B 461)
MANIA
Mania is a manifestation of general excitation of the cerebral cortex. These areas are highly susceptible to influences (anoxia and increased intracranial pressure) which affect the brain generally. In mania the animal act in a bizarre way and appears to be unaware to its surrounding. Maniacal actions include licking, chewing of foreign material, sometimes themselves abnormal voice, walking into strange surroundings and aggressiveness in normally docile animals. Mental disorientation is a component of mania.
Disease characterized by mania include:* encephalitis (the furious form of rabies, Aujeszky’s disease in cattle)* degenerative disease of the brain (early polioencephalomalacia) * toxic and metabolic disease of the brain (pregnancy toxemia, acute lead poisoning, severe hepatic insufficiency in horses)
129. dysgalactia post partum ( M 1020 )
SowPost partum dysgalactia syndrome (PPDS) is characterized by transitory hypogalactia. It can lead to acute multiglandular mastitis.
Clinical signsPPDS is seen within the first 3 days after farrowing. It is associated with fat sow syndrome, prolonged farrowing and high postpartum fever. Management practices include too much manual intervention during parturition or too many parenteral injections to sows (antibiotics, oxytocin) or piglets (antibiotics). Piglet losses are due to emaciation or diarrhea, as a consequence of poor nutrition during the first few days postpartum.
DiagnosisThe diagnosis is based on clinical signs. clinical examination is best performed while piglets are nursing; milk ejection in affected sows is absent or brief duration, which causes the piglets to actively nurse for an extended time. During the initial stages, the piglets repeatedly attempt to nurse at frequent intervals. As a result, the teats may be traumatized. As the energy reserve of the piglets are depleted, their attempts to nurse decrease, and they migrate to warm places. The mammary gland vary from normal to swollen, firm, and warm to the touch. Pure bacteria culture may be isolated from milk samples. rectal temperature of the sow varies from normal to markedly increased (>40.5Oc ). Physiologic hyperthermia observed in lactating sow should not be confused with fever. Reduced appetite to anorexia, constipation and depression may also be seen.
TreatmentSystemic or local therapeutic intervention can sometimes be helpful but only on a short time basis. (antibiotics, glucocorticoid). Oxcitocine or prostaglandin can be useful in cases of prolonged farrowing or postpartum endometritis. 130. the care of parturient cows in large scale herds, its organization and the care of the newborn
as soon as cow shows complete relaxation of the posterior border of the sacroiliac ligament she should be put in a clean, well bedded box and kept under frequent observation (not in Israel). If after
12 hours of restlessness there is no straining a veterinary examination should be made to exclude primary uterine inertia, failure of the cervix to dilate and uterine torsion. If a cow comes into a normal second stage and there is no progress after 1 hour of straining she should be examined to ascertain the cause of the obstructive birth. The immediate approach of labor can be recognized by slackening of the pelvic ligaments and the change of the mammary secretion from a relatively transparent to an opaque cellular secretion – colostrum. When the temperature is checked, change of more than 0.5Oc is a good sign that delivery is going to be occur.
Onset of spontaneous respiration. If parturition occurs normally, spontaneous respiratory movement will occur within 60 second of expulsion; if there is a delay, respiratory movement can sometimes occur before the offspring has been completely expelled (very important in the case of posterior presentation). There are some factors that are responsible for the initiation of spontaneous respiration: * during the birth process PO2 and blood pH are falling and Pco2 is rising due to the start of placental separation and occlusion of the umbilicus → restricting gaseous exchange. If the face of the lamb is cooled with water there is stimulation of respiratory movement, licking and nuzzling of the dam provides some stimulus. Survival of the newborn is dependent upon the rapid onset of normal spontaneous respiration. Once birth is complete it is important first to ensure that the upper respiratory tract is cleared of fluid, mucus and attached fatal membrane. This can be done with the aids of fingers.
Thermoregulation Following birth the body temperature of the newborn falls quickly from that of the dam before it eventually recovers; in the fall and calf the fall is transient; in the lamb recovery occurs within a few hours; the piglets takes up to 24 h or even longer in cold condition; in the kitten and puppy the period before the temperature recovers to that of the birth is 7 – 9 days. The newborn has little subcutaneous fat and insulation is poor. The body surface is wet and heat is lost due to evaporation. Heat lost is greatest in smaller individuals because they have a greater surface area per unit of body weight.
131. perinatal and early postnatal mortality (T 417, B 109)
calves born dead and those that have died by 24 h after birth give a good indication of calving management. Factors contributing to calf mortality are:* condition score of heifers and cows – high condition score have a higher risk for dystocial mortality* sire selection and ease of calving* observation of cows in early stages of parturition * cleanliness of calving area, hands, and equipment if calving difficulties arises* ability and training of individuals working in calving area* colostral management* pneumonia is very important cause of mortality in beef calf followed by exposure to extremely cold weather or being dropped at birth into deep snow. 132. Hypoxia neonatorum (B 119)
Hypoxia can occur as a result of influences during the birth process or they can occur because of pulmonary immaturity in premature birth. a special cause of hypoxia, due to hypovolemia in addition
to inadequate oxygenation of blood, occur in the foal as a result of an inadequate placental blood transfusion when the umbilical cord is severed too early after birth and may lead to neonatal maladjustment syndrome. The response of the neonate to hypoxemia is an increase in blood pressure and a redistribution of cardiac output with increased blood flow to the brain, heart and adrenal gland and a reduction in flow to the lungs, kidney and gastrointestinal tract. Failure of these regulatory changes leads eventually to cerebral anoxia. Maintenance of adequate oxygen supply is essential in the care of hypoxemic and premature foals. Fetal anoxia may be an important cause of the weak calf syndrome. Affected calf are fully developed at birth and may be born with or without assistance. They do not make the usually effort to sit up in sternal recumbency and usually can’t stand even when assisted. They are dull and inactive and the sucking reflex is poor or absent. They may die within few minutes or hours. The cause is unknown, but intrapartum hypoxemia due to prolonged parturition, is considered as a possible cause. In lambs, severe hypoxia during birth results in death shortly following birth and there is an increased risk in those that survive for metabolic acidosis and depressed heat production capacity which causes hypothermia. There is no effective practical treatment for calves affected with intrapartum hypoxia other than the provision of ventilation.
Umbilical bleedingA syndrome of unknown etiology in newborn piglets. Following birth and for periods up to 2 days afterwards, blood drips from the umbilicus of affected pigs to produce severe anemia with death
frequently occurring from crushing. A variable number of piglets within the litter may be affected and the syndrome may have high incidence on certain problem farms. the addition of vitamin K and folic acid to the sow’s ratio may be followed by a drop in incidence. Dosing pregnant sows with vitamin C has been found to be effective. The defect appear to be one of immaturity of collagen so that a proper platelet clot does not form. The navel cords are abnormally large and fleshy and fail to shrink after birth. Vitamin C must be given for at least 6 days before farrowing. Shorter periods of supplementation reduce the severity of bleeding, but do not completely prevent.
Urachus patens
Urachus – fetal canal connecting the bladder with the allantois via the navel. If it fails to close → continuous dripping of urine (from the navel) Failure of the urachus to close at birth occurs most commonly in foals but is also seen in other species. Failure to close causes to leak from the umbilicus. The urine flow varies and may be a continuous stream, dribbling or a continuous moistening of the umbilical stalk. Cystitis is a common sequel but omphalitis and urachal abscess also develop as complication. The urachus can be cauterized with phenol or silver nitrate to induce closure. If cauterization fails, surgical correction is required. When the infection is localized in the urachus, there are usually signs of cystitis, especially increased frequency of urination.
Meconium colic
EpidemiologyColt foals mostly. Worst in dry years Foals which have a narrow pelvis are most susceptible.
Clinical findingFrequent staining. Meconium palpable on rectum. May be severe pain and tympany of large bowel.
TreatmentMedical with lubricants and fecal softener mostly sufficient. Enterotomy rarely.
134. Dyspepsia neonatarum
Etiology – Escherichia coli
pathogenesis + clinical signs = colonize the intestine shortly after birth under certain conditions (changes in the host or bacterium) it becomes pathogenic mucosa adhesions, metabolic dysfunction, death of enterocytes, affect local or systemic vasculature or septicemia : 1. enteric = common in young (after weaning or feed changes) pathogen adhere to mucosa and proliferate in small intestine toxin production stimulate excessive secretion of fluid from intestinal mucosa and goblet cells varying degree of diarrhea.2. enterotoxemic = grow in small intestine produce toxin absorbed and acts elsewhere sudden death (Su.) or anorexia, nervous signs edema (edema disease) vasculitis and necrosis of vessel walls PM changes may be absent (in sudden death) or subcutaneous edema in frontal area, over the snout, in eyelids, submandibular, ventral abdominal and inguinal areas and ln., hydro- pericardium, encephalomalacia in brain stem (associated with lesions in cerebral vessels).** edema disease in Su3. local invasive = man organism penetrate and destroy the intestinal epithelium ulcerative enteritis.4. septicemic = mainly calf mastitis, metritis, cystitis, omphalophlebitis or enteritis E. coli invade the systemic circulation produce endotoxins toxic shock, cardiovascular collapse (hemorrhages on epicardium, endocardium, parietal and visceral pleura), focal ulcers in stomach (or abomasum), hypothermia, coma high mortality and survivors may develop disease due to bacterial localization (arthritis, meningitis, ophtalmitis and pyelonephritis).
Diagnosis isolation of E. coli in large numbers from more than one parenchymatous organ together with gross or microscopic lesions
man is infected by ingestion of undercooked beef, or foods or water contaminated with bovine feces.
135. Omphalophlebitis (B 140)
OmphalophlebitisInflammation of the umbilical veins which may involve only the distal parts from the umbilicus to the liver. Large abscesses may develop along the coarse of the umbilical vein and spread to the liver with the development of a large hepatic abscess which may occupy up to one-half of the liver.
Affected calves are usually 1 – 3 months of age. The umbilicus is usually enlarged with a purulent material. However, in some cases the external portion of the umbilicus is not enlarged. Placing the animal in dorsal recumbency and deep palpation of the abdomen dorsal to the umbilicus in the direction of the liver may reveal a space-occupying mass. Ultrasonography may assist in the diagnosis. Affected valves are inactive, inappetent, and may have a mid fever. Parenteral therapy with antibiotic is unsuccessful. Exploratory laparotomy and surgical removal of the abscess is necessary.
Diagnosis * Place the animal in dorsal recumbency → deep palpation of the abdomen – dorsal to the umbilicus in the direction of the liver → may reveal a space-occupying mass. * ultrasound
136. reproductive efficiency indexes – definitions ( T 400 )
Interval to first estrus – time between the parturition until first estrus Interval to first breeding – time between the parturition and first insemination Days open – the time from parturition until successive insemination First service conception rate – percentage of cows that became pregnant after first insemination Service per conception – number of services which is needed until the cow become pregnant Intercalving interval – amount of cows that become pregnant after first insemination 138. factors influencing the fertility of domestic animals (R&O 346)
the factored which influence the fertility in cows can be divided into two main groups – anatomical factors and functional abnormalities.
Anatomical factors
Both congenital and acquired abnormalities of the genital system can influence fertility, but acquires abnormality are more frequently observed. Anatomical abnormalities usually affect individual cows or heifers and don’t have a major influence on fertility in a herd.
Congenital anomalies * ovarian agenesis one or both ovaries may be absent and in these cases the genital tract is infantile and cyclical behavior is absent. * Ovarian hypoplasia One or both ovaries are small narrow and functionless. When both ovaries are hypoplastic the genital tract is infantile and estrus cycle doesn’t occur.Ovarian hypoplasia should be distinguished from functional anestrus in heifers. In anestrus of heifers, the ovaries are not small, their surface are smooth rather than furrowed and the shape is rounded rather than spindle-like. Also the tubular tract is better develop. This is associated with poor body condition and is reversible when this improves. An extreme form of ovarian hypoplasia may be seen in the bovine freemartin.
* Freemartinism Sterile females born twin to a male. In cattle with multiple conception, the placental blood vessels usually fuse so that a common circulation develops between the fetuses, which allows the antimüllerian ducts hormone and testosterone secreted by the male to inhibit development of the female tract. The tubular genital organs in affected animals range from cord-like bands to near normal uterine horns. Freemartins have a short vagina that ends blind and does not communicate with the uterus. The cervix is absent. The ovaries fail to develop and remain small. In calves(1 – 4 weeks old ) the normal vaginal length is 13 – 15 cm, while in a freemartin it is only 5 – 6 cm. Vaginal length is measured by a well-lubricated probe with a blunt end. The interchange of cells that occur in the placental circulation between the two fetuses can be demonstrated by detecting two different blood types in a single animal.
Acquired abnormalities Lesions of the uterine tube and adnexaThe most frequently observed lesions are between the ovary and the ovarian bursa. The extent of the adhesions varies: they consist of web-like strands in the depth of the bursa, which do not involve the uterine tube. In others there is complete envelopment of the ovary in a closely applied fibrous bursa. The site of ovarian attachment is frequently the scar left from a regressed corpus luteum. Where the bursa is diffusely applied to the ovary, ovulation is prevented and luteinization of the follicles occur. Regressed luteinized follicles of past cycles are often present in the same ovary. Diagnosis of the ovarobursal adhesions in life is difficult and may be impossible. Only half of the lesions that cause infertility are diagnosed by rectal palpation. There is no satisfactory treatment for the condition. Some cases may be prevented if rough manipulation of ovaries and irrigation of uteri with large quantities of irritant antiseptics are avoided.
Adhesions of the uterusAdhesions of the uterus to the omentum, intestine or abdominal wall. A similar lesion may follow uterine rupture. Such lesions may accompany ovarobursal disease. They are frequently associated with sterility. 139. Physical examination of the reproductive system ( T 95, 577,897 )
examination of the female reproductive tract is essential for diagnosis of pregnancy, estimation of the gestational age of the conceptus and characterization of her reproductive physiological pathologic status.
COW
History
Physical examinationThe most accurate method of examination is per rectum palpation of the cervix, uterus, ovaries and supporting structures. Cervix – the palpable characteristics of the bovine cervix change very little with the stages of the estrus cycle.
Membrane slip – from 30days ( the connective tissue band on the lesser curvature of the chorioallantoic membrane
Amniotic vesicle – from 30 – 65 days of gestation ( moveable oval object within the uterine lumen) Placentomes – from 75 days of pregnancy ( soft, thickened lumps in the uterine wall)Palpation of the fetus – only until the fetus “fall” ( after 2 month of gestation) and from 8 month of gestation)
GOAT
Examination can be done only during laparoscopy
SOW
External genitalia Observation of the vulva can help detect potentially sterile or slow-breeding females. The most commonly observed abnormality is the infantile vulva. The infantile vulva is usually accompanied by small, prepubertal ovaries and uterine horns.
140. Infectious pustular vulvovaginitis ( M 1034 )
Infectious pustular vulvovaginitis
Caused by bovine herpesvirus -1 and is transmitted by natural service or by nasogenital contact. It is characterized by vaginal lesions. Affected cows show signs of vaginal discomfort (raised tail, frequent urination) and have many, round, white raised lesions of the vestibular mucosa. Within a short time, these lesions progress to pustules or ulcers. The histologic lesions consist of necrosis of vestibular and vaginal epithelium with intranuclear inclusion bodies typical of herpesvirus infection. The virus may be secreted in the semen of infected bulls (witch have similar lesions of the penis and prepuce). Intrauterine inoculation of the virus produces necrotizing endometritis and cervicitis. In genital infection (of herpes virus 1 ) the first signs are frequent urination, elevation of the tailhead and mild vaginal discharge. The vulva is swollen and small papules are present on the mucosal surface. If secondary bacterial infection do not occur, animals recover in 10 – 14 days.
Diagnosis – uncomplicated BHV – 1 infections can be diagnosed on the characteristic signs and lesions. Samples should be taken early in the disease, and a diagnosis should be possible in 2 – 3 days.
TreatmentAntimicrobial therapy is indicated to prevent or treat secondary bacterial pneumonia. Vaccine (modified live or inactivated virus ) One cause of vulvitis in sheep is ulcerative dermatosis, which is characterized by crusted ulcers of the vulvar skin, penis, prepuce and facial skin.
141. Oophoritis et perioophoritis acuta et chronica
Oophoritis – inflammation of the ovary.
Ovarities, inflammation or infection of the ovary, may occur secondary to trauma, to infection from the uterus that passes through the uterine tubes, or by extension through the uterine walls causing a peritonitis and perimetritis. Trauma may frequently be produced by rough handling or massage of the ovary. Scars, usually star-shaped or transverse, are common in the ovaries of cows where corpora lutea have been enucleated or cysts ruptured by manual manipulation per rectum. Bleeding may occur and hematoma form around the ovary; subsequently this hamatoma organized and produces extensive adhesions. It can disturb passage of sperm or ova and cause infertility.
Treatment – ATB – Sterilization (if damage of CL and follicles or ovaries is severe).
PerioophoritisInflammation of the ovarian surface, infundibulum, broad ligament (mesovarium, mesosalpinx)
EtiologyMetritis, endometritis, pyometra, septic metritisAfter abortionRetained placentaCareless rectal examination → rupture of cysts.Oviduct tuberculosisAdhesions from slight bleeding after ovulation.
142. Reproductive failure in fur animals ( M 1365, 1386 )
Mink
Seasonal breeders (activity correlated with increase daylight) → artificial light may adversely affect photoperiod and interfere to normal reproductive cycle. Breeding season last 4 weeks (late February – early March). Mating should occur within 1 hour of placing the ♀ in the ♂ pen (usually mated again 7 –8 days after) Ovulation is induced by coitus. Pregnancy last 40 – 75 days. Mastitis = E. coli, staphylococcus, streptococcus, Abortion = Proteus, klebsiela Plasmacyosis (Aleutian disease) – poor reproduction (viremia, weight loss, gastrointestinal bleeding) Diethylstilbestrol poisoning → reproductive failure (no estrus, abortion), urinary tract infection Thyroid + parathyroid glands included in meat trimmings fed to mink → aneastrus or silent heat.
RabbitNo estrus = decrease light, vitamin deficiency, nutritional deficiency, over-feeding. Decrease milk = bacterial mastitis → septic (trauma, poor sanitation) → non septic ( = non breeding rabbit → associated with increase estrogen, uterine hyperplasia or uterine adenocarcinoma) PyometraEmbryo mortality = toxins, trauma, stress. Prolapse of uterusTumors (senile trophy of endometrial glandular cells) → papillary cyst, adenoma, hyperplasia.
Chinchilla Mastitis, metritis
Guinea pigInfertility or decreased production of young = bacterial infection Estrogen contaminated feed Genitalia impaction by bedding Wire floors Heat stress Nutritional imbalance Environmental disturbances. Prenatal death =* maternal infection by salmonella, bordetela, streptococcus, treatment is ineffective * Metabolic toxemia (linked to obesity, maturity, anorexia, hypoplasia of uterine artery) only chloramphenicol and sulfonamide can be used safely * asphyxia at delivery (main cause of death at delivery) * dystocia * traumastillbirth is related to litter size * small litter (1 – 2) carried less than 66 days * large litter (>4 ) carried mare than 72 days * any litter born in less than 62 or more than 75 daysabortion = (not related to litter size) = toxemia of the mother dystocia = common is obese ♀→ bloody or green-brown vulvar discharge, exhaustion, depression, large fetus in birth canal atonic uterusmetritis or general debilitation → reproduction decrease, infertility, stillbirth, abortionmastitis (mainly due to low sanitary condition) → milk become dark-red.
144. functional failures of the ovary – generally (R&O 356)
some functional problems occur because of some endocrinological abnormality which is difficult to specify even with current method of hormone assay, when a single sample of blood or milk are examined. The abnormalities occur as a result of inherited factors, nutritional deficiency or access, social influence arises from modern husbandry methods. Cyclic ovarian activity should maintained continuously except during pregnancy and for a short time postpartum. The only way of the farmer to know that this is occurring is the signs of estrus (every 21 days). It is possible that there are signs, but they are not observed.There are some possible causes:* The ovaries may be quiescent and inactive (true anestrus)* there may be normal cyclic ovarian activity but the cow doesn’t show the normal behavioral signs (silent heat)* there may be progesterone- producing structure in the ovary which is exerting an inhibitory effect upon the hypothalamus and anterior pituitary. This may be a persistence corpus luteum or a cyst.
True anestrusThe ovaries are quiescent with an absence of cyclic activity. The reasons may be insufficient release or production of gonadotrophins to cause folliculogenesis. The clinical signs are a cow or heifer which has not been seen in estrus. rectal palpation reveals small ovaries which are flat and smooth, especially in heifers. The main feature is the absence of corps luteum (mature, developing or regressing). Old cows frequently have roughened irregular ovaries because of the presence of old regressed corpora lutea and corpora albicantia. It may be difficult to differentiate between a small developing or regressing corpus luteum and anestrus ovaries. Confirmation can be obtained by reexamination of the cow per rectum after 10 days. In each case the cow in true anestrus will have virtually unchanged ovaries whilst a cow in late diestrus or early diestrus will have a distinctly palpable corpus luteum. Milk or blood progesterone determination are helpful in confirming the diagnosis.
TreatmentImproved feeding, particularly increasing the food intake. Temporary weaning and restricted suckling together with the use of progesterone during the time of calf removal can result in reducing the time to first ovulation postpartum. Equine Chorionic Gonadotrophin (eCG) can be used to stimulate ovarian activity. If the cow is not inseminated there is a possibility that she will relapse into anestrus. Progesterone treatment, together with estrogen, has been used to induce ovarian activity postpartum. These are effective because they stimulate the short luteal phase that usually precedes the first normal estrus cycle or cause an accumulation of gonadotrophin by exerting a negative-feedback effect on the anterior pituitary.
Silent heatThe first and second ovulation postpartum are frequently not preceded by behavioral signs of estrus and are “silent heat”. After the second estrus it is unlikely that many true “silent heat” occur. When ovulation occurs in the absence of observed estrus it is more likely to be the result of a failure of observation than to poor detection. Diagnosis of the condition is made on the clinical history and rectal palpation of the genital system. The corpus luteum must be differentiated from a cyst. It may be persistence or the cow may be pregnant. If there is any doubt then a reexamination should be made in 10 days. Since the accuracy is not 100%, the determination of progesterone in milk or blood can be useful. Treatment – is a mature corpus luteum is present and the cow is not pregnant, PGF2α is indicated.
Persistence corpus luteumAnything which interfere with the production or release of endogenous luteolysin will result in persistence corpus luteum.
Pregnancy is the condition which most frequently result in persistence of the corpus luteum, but in the presence of uterine infection and inflammation of the tissue there is interference with the production or the release of luteolysin. One consequence of this is pyometra which can persist for several month if untreated. The condition can be treated with administration of PGF2α or analogues
145. Ovarian cystic degeneration in the mare - very very rare.
146. ovarian cystic degeneration in the cow ( M 1005)
3 ovarian structures in cattle include the term: cyst. Follicular cyst, luteal cyst and cystic corpus luteum. cystic corpus luteum are known to be a normal stage or variation of corpus luteum development because they are found in normally cycling and pregnant cows without concurrent abnormal reproductive performance. Cystic corpus luteum have a soft, mushy core area, due to presence of fluid from a degenerating blood clot. Cystic corpus luteum are most often detected 5 – 7 days after estrus when the structure is nearing the end of the corpus hemorrhagicum or growth phase.
EtiologyHereditary predisposition has been implicated as an etiological factor. During normal prestrus, regression of the corpus luteum coincides with development of a selected follicle, while the growth of any additional follicles is inhibited. In animals developing cystic ovary disease, ovulation fails to occur and the dominant follicle continues to enlarge. Other follicles may grow and form multiple cyst bilaterally or unilaterally. Follicular cyst resemble enlarged follicles 2.5 – 6 cm in diameter. Th size and form of an affected ovary depends on the number and size of cysts present. The cystic ovary is capable of steroidogenesis and its products can be estrogen, progesterone and androgen.
Clinical signsRelaxation of the vulva, perineum, and the large pelvic ligaments, which causes the tail to be elevated, is common in chronic cases. Some affected cows show these signs, but other may not. This variation is due to the condition and the nature of the hormone signals During the first week, the uterine wall is thickened and edematous as an extension of the preceding estrus. toward the end of the first week, the uterine wall develops a sponge-like consistency. In chronic cases, atony and atrophy of the uterine wall are common. Some degree of mucoid to mucopurulent vaginal discharge is common.
DiagnosisThe larger, multiple cysts are easily identified by rectal palpation. History, conformation and uterine changes, when present, provide supplemental diagnostic evidence. Palpation of the uterus is helpful for differentiation between a single follicular cyst and a mature graafian follicle. Only the estrus cow has a coiled, extremely turgid uterus. Ultrasound is also helpful in diagnosing cyst type (follicular / luteal) and in differentiating cysts from corpora lutea. TreatmentThe oldest treatment s manual rupture – the ovary is grasped and moderate pressure is applied until the cyst burst. After successful rupture, it is recommended that the ovary is compressed to minimize
hemorrhage. Hemorrhage probably occurs most often when the condition is misdiagnosed, and rupture of a corpus luteum or corpus hemorrhagicum is attempted. Hormonally, Human Chorionic Gonadotropin is available and commonly used. Gn-RH are equally effective but less antigenic than HCG. The two products may be alternated when retreatment is necessary.
147. failures in signs of estrous behavior ( T 962)
”silent estrus”mares exhibiting silent estrus show all the physiologic correlation of heat without any of the behavior signs. Tape-recorded sounds of a stallion soliciting mares and breeding them can help, as can the presence of stallion odor. The presence of a known stallion with whom the mare has a good social relationship can help. It may be necessary to permanently or temporarily wean the last foal.
SowOccasionally, gilts may initiate normal ovarian activity but fail to demonstrate estrus or standing heat in the presence of boars. If mated, (A.I ) behaviorally females are fertile. Behavioral anestrus can be differentiated from delayed puberty or prepubertal ovarian status (absence of corpora lutea) by analysis of plasma or serum for progesterone.
CowThe first and second ovulation postpartum are frequently not preceded by behavioral signs of estrus and are “silent heat”. After the second estrus it is unlikely that many true “silent heat” occur. When ovulation occurs in the absence of observed estrus it is more likely to be the result of a failure of observation than to poor detection. Diagnosis of the condition is made on the clinical history and rectal palpation of the genital system. The corpus luteum must be differentiated from a cyst. It may be persistence or the cow may be pregnant. If there is any doubt then a reexamination should be made in 10 days. Since the accuracy is not 100%, the determination of progesterone in milk or blood can be useful. Treatment – is a mature corpus luteum is present and the cow is not pregnant, PGF2α is indicated. 148. Salpingitis acuta et chronica
inflammation of the uterine tubes is characterized by macroscopic enlargement. Lesions are frequently bilateral and consist of infiltration by lymphocytes, plasma cells and neutrophils.
Most cases of salpingitis follow infections of the uterus. Necrotizing and granulomatous salpingitis may follow infection by Actinomyces pyogenes, mycobacterium tuberculosis and brucella abortus. Mild inflammation of the uterine tubes doesn’t result in permanent damage accompanies uterine infection caused by Campylobacter fetus. Salpingitis may be a sequel to manipulation of the ovaries and uterine tubes by palpation per rectum as well as to aggressive irrigation of an infected uterus and inappropriate treatment with estrogenic hormones.
Pyosalpinx is characterized by segmental accumulation of pus within the lumen of the uterine tube following mechanical blockage of either extremity. The tubes are not usually affected over their entire length. Pyosalpinx frequently follows severe cases of uterine infection and may be complicated by perimetritis and localized peritonitis. Hydosalpinx is characterized by accumulation of thin mucus within the lumen of the uterine tube. Hydrosalpinx is a common sequel to chronic salpingitis.
Clinical signsThe usual history associated with diseases of the uterine tubes is infertility. Additional history may or may not include uterine infection or traumatic therapy (uterine irrigation, enucleation of corpora lutea, administration of exogenous estrogen)In cows, lesions involving adhesions between the ovary, ovarian bursa, uterine tube and surrounding tissues may be identified per rectum by inserting two or three fingers into the ovarian bursa and rolling the tube. Diagnosis of diseases of the uterine tubes of ewe and does is impossible by physical examination. Diagnosis is made by observation of the tube by exploratory laparoscopy.
D.DOvarian neoplasia, parovarian cyst, cystic ovarian diseases and ovarian hematomas.
DiagnosisFor suspected unilateral blockage each uterine horn may be catheterized individually with a Foley catheter placed at the base of the horn, on different days.
Treatment Treatment of disease of uterine tubes is not successful. A period of sexual rest may be beneficial and is indicated in valuable animals. The prognosis for reproduction in cases of bilateral obstruction of the uterine tubes is poor.
150. Pyometra (M 1018, 1038 )
large animalspyometra is characterized by the accumulation of purulent or mucopurulent exudate in the uterus. In cows, it is invariably accompanied by the persistence of an active corpus luteum. In affected mares,
the cervix is often found to be fibrotic, inelastic, affected with transluminal adhesions, or in some other way impaired. Mares may continue to cycle normally, or the cycle may be interrupted. Discharge from the genital tract may be absent or intermittent and corresponding to periods of estrus. affected animals do not exhibit any systemic signs of illness.
Treatment – in cows, administration of PGF2α at normal luteolytic doses. Expulsion of exudate and bacteriologic clearance of the uterus follows 90% of treated cases. In mares, lavage of the uterus using large volumes of fluid is recommended, but the condition frequently recurs, and permanent cure in these cases requires hysterectomy. If pyometra is diagnosed in mall ruminants and swine, evacuation of the uterus is recommended.
Small animalsPyometra is a hormonally mediated diestrual disorder characterized by an abnormal uterine endometrium with secondary bacterial infection. In the normal bitch, the corpora lutea produce progesterone for 9 – 12 weeks after ovulation in each estrus cycle. In the cat, if pregnancy does not occur after a cat is induced to ovulate, the life span of the corpora lutea is 45 days.
EtiologyFactors associated with pyometra include administration of long-lasting compounds to delay or suppress estrus, administration of estrogens to dismated bitches and post-insemination or post-copulation infections. Progesterone promotes endometrial growth and glandular secretion while decreasing myometrial activity. Bacteria from the normal vaginal flora or subclinical urinary tract infection are the source of uterine contamination. E. coli is the most common bacterium isolated in case of pyometra, but also staphylococcus and streptococcus can be found. Because queen require copulatory stimulation to ovulate, form corpora lutea, and produce progesterone, pyometra is less common in queens than in bitch. Pyometra can develop in uterine tissue left after ovariohysterectomy. Pyometra can also occur secondary to postpartum metritis. Estrogen, by itself, does not contribute to the development pyometra → it increases the stimulatory effect of progesterone on the uterus. Administration of exogenous estrogens to prevent pregnancy during diestrus greatly increases the risk of developing pyometra.
Clinical signsClinical signs are seen during diestrus, usually 4 – 8 weeks after estrus, or after administration of exogenous progestins. The signs are variable and include lethargy, anorexia, polyuria and vomiting. When the cervix is open, a purulent vulvar discharge, often containing blood, is present. When the cervix is closed, the large uterus may cause abdominal distention. Signs can progress rapidly to shock and death. Physical examination shows lethargy, dehydration, uterine enlargement and mucopurulent vaginal discharge.
DiagnosisPyometra should be suspected in any ill, diestrual bitch or queen, especially if PU / PD or vomiting is present. The diagnosis can be established from the history, physical examination and abdominal radiography and ultrasound. Vaginal cytology is often helpful in determining the nature of the vulval discharge. The uterine exudate should be cultured and sensitivity test performed.
TreatmentOvariohysterectomy is the treatment of choice, but medical management can be done if it is needed. Fluid (I.V) and broad spectrum antibiotics should be administrated. Fluid, electrolyte and acid-base imbalances should be corrected before the surgery. The bacterial infection is responsible for the illness and will not resolve until the uterine exudate is removed. Oral antibiotics should be continued for 7 – 10 days after surgery.
Medical therapy with prostaglandins (PGF2α ) can be used for animals to be bred in the future. Prostaglandins cause luteolysis, contraction of the myometrium, relaxation of the cervix, and expulsion of the uterin exudate. PGF2α should be used with caution in the bitch or queen with a closed-cervix pyometra bacause the risk of uterine rupture is increased. Pregnanc must be ruled out because prostaglandins can induce abortion. Broad-spectrum, bactericidal antibiotics, should be given for at least 2 weeks. PGF2α can cause restlessness, panting, hypersalivation, abdominal pain, vomiting, urination and defecation. In cats, vocalization and intense grooming may be seen. These reaction disappear within 2 h of the injection. The animal should reexamined 2 weeks after. If mucopurulent vulval discharge or uterine enlargement is still present, PGF2α mat be repeated.
151. Endometritis in the mare ( T 718 )
PathogenesisThe action of the cervix, vestibular sphincter and vulva promotes removal of foreign material during estrus. mucus exudated and transudated flow outside while air and surface contaminants are excluded.
Neutrophils migrate from the circulation to the uterine lumen where they ingest and kill contaminating organisms. These cells are than eliminated mechanically. (fertile mare during early postpartum period.) the bacteria that gain access to the uterus during parturition and those deposited during breeding within the first 2 weeks are eliminated in 5 days after ovulation to allow pregnancy to become established. Aging, repeated foaling, anatomic breakdown and slowing of the cellular immune mechanisms eventually decrease the efficiency of bacterial clearance. If the uterine environment suffers from a prolonged inflammatory process, embryos die and mares recycle. The causal organisms of endometritis are common surface, fecal and soil bacteria. Streptococcus and pseudomonas are easily transferred to the uterus during breeding, foaling or examination. The severity of the contamination is unimportant in healthy mares. Failure of uterine defenses may occur abruptly following serious trauma to the reproductive tract, or gradually.
DiagnosisDiagnostic procedures should be targeted at detecting the signs of inflammatory change. Changes in the tubular tract can be detected by rectal or vaginal examination. Examination of the vaginal tract and cervix is done with a speculum. Changes in color of the mucosa, presence of exudate originating beyond the cervix or pooling in the vagina and traumatic lesions may be detected through the speculum. Rectal palpation of the uterus and cervix may suggest fluid accumulations in the uterus or local lesions in the tract. Support for the diagnosis may come from examining uterine cytology or endometrial histology. The bacterial pathogens involved in endometritis are Streptococcus, E. coli, Pseodomonas and Klebsiela
Therapy* correction of anatomic defects when indicated* reduction of the inflammation and bacterial numbers in the uterus – administrated locally (intrauterine) or by systemic routs. * prevention of recurrence of the disorder.
152. diseases of vulva and vagina, urovagina and vaginismus (T 345, 476, 479)
UrovaginaPooling of urine in the anterior portion of the vagina can be a cause of infertility. The condition is instigated by congenital or acquired cranioventral tipping of the pelvis, so the external urinary meatus is higher than the anterior pelvic floor, thus directing the urine flow inward. The collection of
increasing volume of urine in the anterior part of the vaginal vault induces drooping of the dilated vaginal vault into the abdominal cavity. The external cervical os is bathed in urine that may permeate the cervical canal and fill the uterus. Treatment – surgery
Segmental vaginal Aplasia
Segmental aplasia of the müllerian duct system is seen in cattle ( “white heifer disease”) and dogs. The occlusion created may be partial (hypoplasia ) or complete ( aplasia) and can occur anywhere along the vaginal wall. Hypoplastic conditions may only become apparent in bitches during natural breeding or parturition. Complete partitioning of the vaginal fluid during the estrus cycle can be confused with a closed-cervix pyometra. In breeding animals caudal and mid-vaginal stricture can be resect, and the vaginal segment are anastomosed. No treatment is required for a non-breeding, asymptomatic female with partial obstruction. Non-breeding symptomatic animals are treated by ovariohysterectomy and/or vaginectomy.
Congenital anomaliesCongenital anomalies may contribute to the formation of vaginitis, cystitis and difficulty in breeding.
Vulvar stenosisVulvar stenosis is detected at the junction between the vestibule and the vulvar labia and is thought to be the result of an imperfect fusion of the genital folds or genital swelling. An episiotomy can be performed to enlarge the strictured region permanently in order to prevent difficult mating and potential dystocia. Without surgical correction affected bitches require artificial insemination.
Atretic vulvaWhen vulvar hypoplasia or atrophy occur, the vulva appears small or infantile and is frequently retracted into the perineal skin folds. The condition is usually recognized in spayed females, who clinically present with a moist, perivulvar dermatitis caused by retention of urine within the skin folds. Estrogen therapy can b used to maintain normal vulvar size. Continual estrogen administration is required for its effectiveness, which may result in fatal bone marrow suppression. Exteriorization of the vulva is the treatment of choice.
155. Trichomoniasis (M 1027, R&O 405 )
A venereal protozoal disease of cattle characterized by early fatal death and infertility, resulting in extended calving intervals.
Etiology
The causative protozoan, trichomonas fetus, is found in the genital tract of cattle. When cows are bred naturally by an infected bull, 31 / 90% become infected. Bull s of all ages can be infected but this is less likely in younger males. Transmission can also occur when the semen from infected bulls is used for artificial insemination.
Clinical signsInfection is characterized by low pregnancy rates, a profuse mucopurulent vulval discharge, early abortion and pyometra. Cows and heifers which have been exposed to infected service can be:* full pregnancy without clinical signs of infection developing. * fail to conceive and develop an edematous condition of the endometrium. * conceive but abort at 2 – 4 months of gestation. * develop pyometra and become acyclic.
The organism produces a catharrhal endometritis and vaginitis with edema of the vulva, perivaginal tissue and uterine wall. Affected animals show vulval discharge and on rectal palpation the uterus is enlarged and flaccid. Manipulation of the uterus provoke a discharge from the vulva and motile trichomonas can be demonstrated on it.
DiagnosisAlthough clinical signs and history support the diagnosis, a positive diagnosis can be made by identification of the organism. The best source of material are the fatal membrane or the organs of an aborted fetus. The organism can be identified in vaginal mucus or mucopurulent discharge. In cases of pyometra, the pus should be examined because large numbers of trichomonas will be there. The material should be examined as soon as possible after collection.
TreatmentWhen more than one bull is being used in the hers, the general attitude is that all the cows are carriers despite the fact that examination indicate that one or other of them has not been exposed to infection.
156. Campylobacteriosis (Merck 997)
EtiologyCampylobacter fetus venerealis, Campylobacter fetus fetus.Campylobacter fetus is transmitted venereally and also by contaminated instruments or by artificial insemination using contaminated semen. The duration of the carrier state is variable; some clear the infection rapidly, while other can carry the bacteria for more than 2 years.
Clinical signsA venereal disease of cattle characterized primarily by early embryonic death, infertility and occasionally abortions.Cows are systematically normal, but there is a variable degree of mucopurulent endometritis that causes early embryonic death, prolonged luteal phases, and a protracted calving season.Generally in the herd, the pregnancy percentage will be low, great variations in gestation lengths.The first signs of genital vibriosis can be detected by the farmer by the number of cows that return to service by a newly introduced bull. Some return regularly, some irregularly. Bulls are asymptomatic and produce normal semen.
DiagnosisVibriosis is suspected when a majority of cows or heifers are returning regularly or irregularly to service. Campylobacteriosis and trichomoniasis are similar syndromes, and investigations should be directed at both diseases. Vaginal culture immediately after abortion or infection but the number of organisms may be low. It is difficult to isolate the organism – it survives only 6-8 hours after collection, collection of smears from the prepucial sac. Bulls should be sampled twice, 1 week apart. Swabs from the placenta might be contaminated with the non-pathogenic fecal campylobacter sp.Some diagnostic test can be used to diagnose Campylobacter fetus infection.
* direct smear or culture* vaginal mucus agglutination test
TreatmentTreatment is not needed because infected cows overcome the infection, or become immune after3 – 6 months.
Vibriosis (sheep) (M 993 R&O 456)
Etiology: Campylobacter fetus results in abortions in late pregnancy or stillbirth.
Clinical signs:Abortion can occur in late gestation, usually in the last 6 weeks. Vulval swelling and the presence of a reddish-colored vulval discharge occur in some animals. Ewes may develop metritis after expelling the fetus. Placentitis occurs with hemorrhagic necrotic cotyledons and edematous or leathery intercotyledonary areas. The fetus is outolyzed, sometimes with necrotic foci on the liver.
Diagnosis:Finding of organism in darkfield preparations from abomasal or placental smears or in uterine discharge.
Treatment and control:
Strict hygiene for stopping the outbreak (isolation of the suspected animal ). Tetracycline may help prevent exposed ewes from aborting. The disease tends to be cyclical, with epizootic occurring every 4 – 5 years, therefore, vaccination programs should be applied.
158. special investigational procedures in the gynecological practice (biopsy of endometrium, laparoscopy, diagnostic of tubal obstructions)
Biopsy of endometrium (mare) * luminal content may indicate presence of uterine fluid or exudate
* epithelial type is related to the hormonal status → cuboidal = estrus. columnar ( low to tall) = breeding season * trans-epithelial cells may indicate inflammation = neutrophil → acute reaction lymphocytes + plasma cells → chronic reaction focal /diffuse cellular pattern, amount of cells, degree of infiltration → severity of inflammation. * peri-glandular fibrosis (fibrotic nests) → may interfere with endometrial gland function and may be a factor in early embryonic death (we can also find glandular distention – which is normally found during pregnancy, but here it indicate that the fibrosis obstructs the gland = cystic glandular distention)
* the endometrium is classified into 3 categories: I – no significant changes and no treatment is required Endometrium with any peri-glandular fibrosis will not be classified here. The estimated foaling rate is 80 – 90 % II – divided into 2 categories:(broad category that includes mast mares)II A = mare with less severe changes → estimated foaling rate is 50 – 80 % II B = mare with more severe changes → estimated foaling rate is 10 – 50 %
Therapy may be indicated to improve the state of the endometrium by reducing the inflammation, cystic glandular distention, and lymphatic lacunae → improvement may be followed by re-classification (there is no effective treatment to reduce peri-glandular fibrosis) III – endometrium with wide-spread, severe changes (including glandular fibrosis or inflammation) Estimated foaling rate is < 10%
Laparoscopy ( T 779)It is important to histologically evaluate the extent of normal, unaffected endometrium (not with the presence of any particular lesions). Indication for diagnostic Laparoscopy* infertility* ovarian biopsy* biopsy of pelvic masses* microbiologic culture of the infundibulum* aspiration of cysts* AI in sheep* Exploration of genital tract in sheep
the instruments for laparoscopy include a laparoscope, a trocar with sheath to permit introduction of the instrument through the abdominal wall, a verres needle and a light source with a fiberoptic conduction system. A surgical laparoscope will permit passage of a biopsy forceps, which can be utilized to obtain samples from the ovary and other pelvic organs. Other instruments that may be introduced through a laparoscope include probes for manipulation, swabs for obtaining samples from the infundibulum for microbiologic culture and suction equipment for obtaining ovarian fluid.
The technique involves the insertion of a biopsy instrument through the cervix and into the uterus. With the biopsy instrument in the uterine lumen, a gloved hand is inserted into the rectum to allow manipulation of the instrument into the desired position. The sample is taken by closing the jaws of the instrument and tugging sharply. To avoid damage, the tissue is carefully transferred into a fixative solution with a fine needle. If the uterus appears normal on palpation, the sample should be
taken from one of the areas of embryo fixation – the uterine-horn body junction on either side. If the uterus is abnormal on palpation, the sample should be taken from both the affected area and a normal area.
Diagnosis of tubal obstruction
1. rectal palpation = rotation of the right ovary by the left hand – in order to free it from the bursa (opposite for other hand) ↓ held tightly between the thumb and fore-finger, while the other 3 fingers are extended into the bursa ↓ detect adhesions between the ovary and bursa2. laparotomy → Endoscopy → direct vision of the ovary + bursa3. starch particles = stimulate the transport of oocyte or zygote4. phenol- sulfur – phtalein absorption ( PSP test)
20 ml of 1% PSP is placed in the uterine lumen (not absorbed there but pass-on) ↓if the oviduct are opened, the PSP passes along them into the peritoneal cavity where it is absorbed into the blood ↓excreted by the kidney into the uterine ( within 30 – 60 minutes) ↓0.2 ml of 10% trisodium ortho-phosphate buffer is added to 10 Ml urine (turn the urine to alkali) ↓If PSP is present – the urine will become pink or red (if the oviduct is occluded → no passage of PSP → no discoloration of urine)
* False positive in case of endometrial erosion (due infection and inflammation ) or during follicular phase of cycle* a more accurate method which examine each oviduct separately: a Foley-type embryo-flushing catheter is introduced into one horn ↓ the cuff is inflated to prevent reflux of dye to the other side ↓ a small amount of dye is infused into the tip of the horn ↓ if the duct is patent – the dye will appear in urine
159. examination schedule for a dairy reproductive program
the examination can be divided into 3 parts: * early puerperium examination 10 – 14 days after parturition* 30 days postpartum* early pregnancy diagnosis
puerperium examinationinvolution – reduction in the size of the genital tract. The greatest change occur during the first few days after calving. Uterine contraction continue for several days. The speed of involution of the non gravid horn is more variable than that of the previously gravid horn, which depends upon its degree of involvement in placentation. The cervix constrict rapidly postpartum. After 96 hours it will admit just two fingers. The cervix also undergo atrophy and shrinkage due to the elimination of fluid and the reduction in muscle tissue. During the firs 7 – 10 days after parturition there is loss fluid and tissue debris.
30 days postpartumhormonal level and return of normal ovarian activity
Early pregnancy diagnosisPregnancy diagnosis can be done by the determination of the progesterone concentration in the plasma of cows. The corpus luteum persist as a result of the pregnancy – if a blood sample is taken at 21 days after the previous estrus progesterone levels remain elevated. If the cow is not pregnant and is close to or at estrus then the progesterone level will be low. The changes in progesterone concentration in the milk closely follow those in the blood or plasma.
Palpation of the amnionic vesicleIt is possible to identify the amnion towards the end of the first month of pregnancy. The bifurcation of the uterine horn is located, the horn uncoiled and gently palpated along their entire length between the thumb and middle two fingers. The amniotic sac can be felt as a distinct, round turgid, 1 – 2 cm in diameter floating in the Allantoic fluid.
Palpation of the allantochorion (membrane slip)In the cow, attachment of the allantochorion to the endometrium occurs only between the cotyledons and the caruncules and the intercotyledonary part of the fatal membrane is free. (5 weeks of gestation). Identify the bifurcation of the uterine horns, pick up the enlarged, gravid horn between thumb and the index finger just cranial to the bifurcation and gently squeeze the whole thickness of the horn. The allantochorion is identified as a very fine structure as it slips between the thumb and finger before the uterine and rectal walls are lost from grasp.
Unilateral cornual enlargementPalpation of the early fetus ( 45 – 50 days of gestation)
163. reproductive management of large dairy herds- quality control of human factors (fertility disturbances due to human factors)
No observed estrus = ignorance of true signs Herd is too large to detect Short duration of estrus + activity at night Overcrowding False identification of the cow.
Too short time spent on observation Incorrect timing of AI Nutritional deficiencyNutritional excess (overfeeding)Injury to animal due to careless manipulation / examination / milkingIncorrect procedure of AI Stress (overcrowding, careless, manipulation, rough handling) Undetected diseasesUntreated diseases Incorrect assistance in delivery → calf may die + ♀ can be injured, uterus prolapse Lack of assistance during calving (the farmer didn’t recognized dystocia)Careless handling of herd-bookCareless identification of animals (wrong numbers, unclear numbers)
164. Cervicitis – etiology and symptoms ( R&O 395 ) inflammation of the cervix occur after obstetric trauma incurred during the relief of difficult dystocia, and in this circumstances, it usually accompanies puerperal metritis. (it occurs also after retained placenta ). The organisms present in these infections are those normally found in the posterior vagina : E. coli, streptococcus, staphylococcus and Campylobacter pyogenes, which is the most infective. Third degree perineal laceration due to calving trauma result in cervicitis due to fecal contamination. The treatment is surgical correction. Cows were diagnosed as having urovagina. In such animals urine accumulates in the anterior vagina penetrate into the cervix, and causes inflammation of the cervix. The inflammation than extends into the uterus, causing endometritis. Stretching of the suspensory apparatus of the genital tract as a result of several pregnancies may be a factor. Surgical treatment can be one.
165. collection of samples for laboratory investigation in cases of infertility (T 424, 457) Endometrial biopsy of cow
Repeated biopsies don’t cause adverse effect of the cow’s reproductive tract. The lesions resulting from the biopsy heal rapidly. Hemorrhages are quickly absorbed. Specimens should be taken from the left and right horns and the body of the uterus. The instruments should be sharp in order to avoid artifacts.
The biopsy instrument consist of 2 concentric tubes. The outer tube is made of steel, while only the proximal portion of the inner tube is made of steel. This proximal part contains a sharp cutting edge for cutting the endometrium. The outer tube has a small window near its tip that can be opened by the inner tube. The instrument is placed in a cylindrical speculum. Other biopsy instrument include alligator type forceps with a biopsy punch. The tissue specimen should be removed and immediately immersed in a fixating solution to prevent drying out. (10% formalin) The biopsy specimens are cut and stained with hematoxylin and eosin. The bovine endometrium can be evaluated for periglandular fibrosis and cystic glandular changes. They are considered pathologic lesions of the uterus. Periglandular cysts is the most frequent abnormality found in cows. The severity is based on the visibility and clarity of the fibroblast surrounding the endometrial glands in the connective tissue stroma. Varying degrees of fibrosis between each horn and body of the uterus may exist simultaneously. As the number of normal sections in a cow’s uterus decreases and the degree of fibrosis increases, there is a trend toward poorer conception. The occurrence of cystic glands show no significant relationship to breeding performance. Mild chronic endometritis is one of the most common causes of repeat breeders. The majority of cows with clinical deviations of the reproductive tract show endometritis in varying degrees. Some cows with mild endometritis are able to conceive and maintain a pregnancy.
Bacteriological swab (bitch)
blood or milk can be evaluated for progesterone level→ identify the luteal tissue serum → specific serologic tests (mucus agglutination test, fluorescent –AB test for campylobacter fetus)
semen evaluation
166. Freemartinism, Hermaphroditism, Infantilism ( M 987, T 900 )HermaphroditismMay occur in all species but it is most common in goats and pigs. True hermaphrodites have both ovarian and testicular tissue and exhibit anomalies of the external genitalia. Pseudohermaphroditism are more common; they have one or the other type of gonad and an anatomy of the external genitalia that resembles, that of the opposite sex. The male hermaphrodite I more common, with testes in the abdominal cavity or beneath the skin in the scrotal region, and external genital organs that resemble those of females. The müllerian ducts are paired embryonic ducts that develop into the anterior vagina, cervix, uterus and oviducts. Segmental aplasia of the müllerian ducts leads to various anomalies of the vagina, cervix , uterus and oviducts. The ovaries develop normally. Developmental obstruction of the tubular tract mat lead to accumulation of secretions anterior to the obstruction. The most common aberration is a variable degree of persistence of the hymen. Segmental aplasia of the uterus may involve one horn ( uterus unicornis ), both horns, or only part of one horn (which may result in cystic dilatation of the uterine horn anterior to the area of dilatation ).
FreemartinsSterile females born twin to a male. In cattle with multiple conception, the placental blood vessels usually fuse so that a common circulation develops between the fetuses, which allows the antimüllerian ducts hormone and testosterone secreted by the male to inhibit development of the female tract. The tubular genital organs in affected animals range from cord-like bands to near normal uterine horns. Freemartins have a short vagina that ends blind and does not communicate with the uterus. The cervix is absent. The ovaries fail to develop and remain small. In calves(1 – 4 weeks old ) the normal vaginal length is 13 – 15 cm, while in a freemartin it is only 5 – 6 cm. Vaginal length is measured by a well-lubricated probe with a blunt end. The interchange of cells that occur in the placental circulation between the two fetuses can be demonstrated by detecting two different blood types in a single animal.
InfantilismA common abnormality in pigs and is generally associated with confinement-reared gilts. The presence of a very small vulva and the absence of estrus are suggestive of this condition. The infantile tract is 30% of the size of a tract from a normally cycling gilt. The ovaries are hypoplastic and nonfunctional, with numerous small follicles and no corpora lutea. This condition is common in gilts with delayed puberty or gilts less than 6 months of age.
167. ovarian hypoplasia
Hypoplasia of the ovaries This defect is conditioned by a single recessive autosomal gene with incomplete penetration. This Gene affects both cows and bulls in equal proportions. The affected ovary may be partially or totally hypoplastic. Depending on the severity of the hypoplasia and whether the condition is unilateral or bilateral, infertility or sterility will result. In the latter instance the affected heifer is an-estrous. This condition can be recognized in affected heifers by rectal examination as early as 9 months of age. The incidence of partial or transitional hypoplasia occurred in about the same percentage as the total hypoplasia of the ovaries or testes. These intermediate conditions can be evaluated only by repeated rectal examinations of the ovaries over a period of time or at the time of slaughter. The hypoplastic ovary undergoes incomplete development and a part or the whole ovary lacks a normal number or complement of primordial follicles. Both ovaries of normal heifers contained a total of 50,700 primordial follicles, range 6,800 to 100,000. Both ovaries, in affected heifers in which one ovary was totally or partially hypoplastic averaged 19000 to 23000 primordial follicles. In affected heifers with bilateral hypoplasia there were fewer than 500 primordial follicles in partially affected ovaries and no follicles were present in the heifers with totally hypoplastic ovaries. In heifers the hypoplastic ovary is so small that it may be difficult to locate. It is a thin, narrow, structure of firm consistency, or in severe cases only a cord-like thickening, in the cranial border of the ovarian ligament. The ovary has a shriveled or shrunken appearance affecting the entire ovary in total hypoplasia or usually the medial half or two-thirds of the ovary in partial hypoplasia. In other cases one-half of the ovary feels slightly raised and firm like a pea. In other cases the ovary of an adult cow may feel like a kidney bean with the surface smooth and stretched. If the surface of the ovary is rough due to luteal scars the ovary can be considered functional. In one-sided hypoplasia the tubular portion of the genital tract develops normally. In bilateral total hypoplasia the genital tract remains very small and infantile; estrus does not occur and there is no development of the secondary sex characteristics due to a lack of estrogens.
In ovarian hypoplasia treatment with hormones is useless. The condition of hypoplasia should be differentiated from nonfunctional or atrophic ovaries in cows and small, inactive ovaries in heifers associated with a delayed onset of puberty due to inanition or underfeeding.
168. Dairy herd management system (T385)
170. mastitis-metritis-agalactia syndrome ( B 618 )
The MMA syndrome occurs in sows between 12 – 48 h after farrowing.
EtiologyThe precise etiology has not yet been determined. The list of proposed causes include infectious mastitis, metritis, overfeeding during pregnancy, nutritional deficiency and endocrine dysfunction. The disease occur most commonly in sows which are farrowed indoors and only occasionally in sows farrowed outdoors. The predisposing factors include overfeeding during pregnancy, a drastic change of feed at farrowing, insufficient time for the sow to adjust to the farrowing crate after being transferred from the gestation unit and constipation of the sow at farrowing. The incidence of the disease is higher in sows with large litters. Sows that had high-level feeding during pregnancy are more susceptible to the disease, especially if the food was changed immediately prior to parturition.
Clinical signsThe sow is usually normal with a normal milk flow for the first 12 –18 h after farrowing. One of the first indication of the disease is the failure of the sow to suckle her piglets. She is interested in the piglets, generally lies in sternal recumbency and is unresponsive to the suckling demands. Litters of affected sows are more noisy and search for alternative food supply. The piglets may drink surface water or urine and infectious diarrhea may occur. Many piglets may die from starvation and hypoglycemia. Some sows are initially restless and stand up and lie down frequently which contribute to a high mortality from crushing and tramping. Affected sows do not eat, drink very little and are generally lethargic. The body temperature is usually elevated from 39.5 to 41Oc. mild elevation in body temperature of sows in the first 2 days after parturition occur also in normal healthy sows. In the mammary gland there is swelling and inflammation. There may be extensive subcutaneous edema around and between each section which result in a ridge of edema on the lateral aspect of the udder. The teats are usually empty and may be slightly edematous.
TreatmentMost affected sows will recover within 24 – 48 h if treated with a combination of antimicrobials, oxytocin and corticosteroid. Antimicrobials are indicated in most cases because infectious mastitis is one of the most common causes of the disease. The choice is determined by previous experience in the herd. The antibiotic should be given daily for at least 3 days. If there is a beneficial response to oxytocin treatment, the piglets should be placed on the sow if she is willing to allow them to suck. This will assist in promoting milk flow. Massage of the mammary gland with warm water may assist in reducing the swelling and inflammation and promote the flow of milk. The piglets must be given a supply of milk and/or balanced electrolyte and dextrose until the milk flow of the sow is resumed.
171. failures of estrus cycle (R&O 356, 523)
True anestrusThe ovaries are quiescent with an absence of cyclic activity. The reasons may be insufficient release or production of gonadotrophins to cause folliculogenesis. The clinical signs are a cow or heifer which has not been seen in estrus. rectal palpation reveals small ovaries which are flat and smooth, especially in heifers. The main feature is the absence of corps luteum (mature, developing or regressing). Old cows frequently have roughened irregular ovaries because of the presence of old regressed corpora lutea and corpora albicantia. It may be difficult to differentiate between a small developing or regressing corpus luteum and anestrus ovaries. Confirmation can be obtained by reexamination of the cow per rectum after 10 days. In each case the cow in true anestrus will have virtually unchanged ovaries whilst a cow in late diestrus or early diestrus will have a distinctly palpable corpus luteum. Milk or blood progesterone determination are helpful in confirming the diagnosis.
TreatmentImproved feeding, particularly increasing the food intake. Temporary weaning and restricted suckling together with the use of progesterone during the time of calf removal can result in reducing the time to first ovulation postpartum. Equine Chorionic Gonadotrophin (eCG) can be used to stimulate ovarian activity. If the cow is not inseminated there is a possibility that she will relapse into anestrus. Progesterone treatment, together with estrogen, has been used to induce ovarian activity postpartum. These are effective because they stimulate the short luteal phase that usually precedes the first normal estrus cycle or cause an accumulation of gonadotrophin by exerting a negative-feedback effect on the anterior pituitary.
Ovarian cystic degeneration3 ovarian structures in cattle include the term: cyst. Follicular cyst, luteal cyst and cystic corpus luteum. cystic corpus luteum are known to be a normal stage or variation of corpus luteum development because they are found in normally cycling and pregnant cows without concurrent abnormal reproductive performance. Cystic corpus luteum have a soft, mushy core area, due to presence of fluid from a degenerating blood clot. Cystic corpus luteum are most often detected 5 – 7 days after estrus when the structure is nearing the end of the corpus hemorrhagicum or growth phase.
EtiologyHereditary predisposition has been implicated as an etiological factor. During normal prestrus, regression of the corpus luteum coincides with development of a selected follicle, while the growth of any additional follicles is inhibited. In animals developing cystic ovary disease, ovulation fails to occur and the dominant follicle continues to enlarge. Other follicles may grow and form multiple cyst bilaterally or unilaterally. Follicular cyst resemble enlarged follicles 2.5 – 6 cm in diameter. Th size and form of an affected ovary depends on the number and size of cysts present. The cystic ovary is capable of steroidogenesis and its products can be estrogen, progesterone and androgen.
Clinical signsRelaxation of the vulva, perineum, and the large pelvic ligaments, which causes the tail to be elevated, is common in chronic cases. Some affected cows show these signs, but other may not. This variation is due to the condition and the nature of the hormone signals During the first week, the uterine wall is thickened and edematous as an extension of the preceding estrus. toward the end of the first week, the uterine wall develops a sponge-like consistency.
In chronic cases, atony and atrophy of the uterine wall are common. Some degree of mucoid to mucopurulent vaginal discharge is common.
DiagnosisThe larger, multiple cysts are easily identified by rectal palpation. History, conformation and uterine changes, when present, provide supplemental diagnostic evidence. Palpation of the uterus is helpful for differentiation between a single follicular cyst and a mature graafian follicle. Only the estrus cow has a coiled, extremely turgid uterus. Ultrasound is also helpful in diagnosing cyst type (follicular / luteal) and in differentiating cysts from corpora lutea. TreatmentThe oldest treatment s manual rupture – the ovary is grasped and moderate pressure is applied until the cyst burst. After successful rupture, it is recommended that the ovary is compressed to minimize hemorrhage. Hemorrhage probably occurs most often when the condition is misdiagnosed, and rupture of a corpus luteum or corpus hemorrhagicum is attempted. Hormonally, Human Chorionic Gonadotropin is available and commonly used. Gn-RH are equally effective but less antigenic than HCG. The two products may be alternated when retreatment is necessary.
Prolonged prestrus / estrus (bitch)The normal interval between the onset of prestrus and ovulation varies from 5 – 30 days. Most bitches ovulate by day 14 after the onset of prestrus, and those with ovulate later than this are often considered to have prolonged estrus. these animals do not require treatment but careful assessment of the optimal mating time. Cases in which prestrus or estrus persist longer than 30 days require treatment. the induction of ovulation may be attempted by the administration of hCG (20 IU / kg) Estrogen-secreting follicular cyst are very rare in the bitch, but these may produce persisting estrus. similar clinical signs may be seen with estrogen-secreting ovarian tumors where high concentration of estrogen may lead to bone marrow suppression resulting in anemia. In such cases, treatment is by unilateral ovariectomy.
173. Luteolysis – mechanism ( T 120, 481, 914 )
Cow Estrogen, produced primarily by a developing large antral follicle, initiate the process of luteal regression during late diestrus via induction of uterine PGF2 production. Administration of exogenous estrogens initiate luteolysis in cattle and has been shown to stimulate uterine PGF2 production during late diestrus. Uterine involvement in the luteolytic processes is supported, since prolonged maintenance of CL function results after surgical removal of the uterus during mid-diestrus.In cow and sheep, ovarian oxytocin is released during luteolysis. Oxytocin increase uterine PGF2 release and ensure rapid and complete luteal regression.
Bitch
PGF2 can be used to induce abortion in healthy bitches from mid-gestation to term, and a dosage of 25 to 250 μg / kg, I.M can be used. The effect is faster as the pregnancy progress.
SowThe porcine CL remains unresponsive to the acute administration of PGF2 until days 12 – 14 after ovulation. Prior to this time, treatment with prostaglandins causes no decline or only a transient decline in circulating levels of progesterone.
174.Fat cow syndrome (fatty liver disease of cattle ) as a cause of reproductive failure (M 731, B 1356)
fatty liver is most common in periparturient cattle. It usually develop before and during parturition. Endocrine changes associated with parturition and lactogenesis contribute to the development of fatty liver.
Etiology Fatty liver occurs during periods when blood concentration of nonesterified fatty acids (NEFA) are increased. The most dramatic increase occurs at calving. Uptake of NEFA by the liver is proportional to the concentration in the blood. NEFA taken up by the liver can be oxidized or esterified. The primary esterification product is triglyceride, which can be exported or stored. In ruminants export occurs at a very low rate; therefore, under condition of increased hepatic NEFA uptake and esterification, triglyceride accumulation occurs. Oxidation of NEFA leads to the formation of co2 and ketones. Ketone formation is favored when blood glucose concentrations are low. Conditions that lead to low blood glucose also contribute to fatty liver because insulin suppresses fat mobilization from adipose tissue. The greatest increase in liver triglyceride occurs at calving. The extent to which feed intake is depressed before and after calving or during disease moderate the degree of infiltration of triglyceride. Because of the slow rate of triglyceride export, once fatty liver has develop, it will persist for an extended period of time.
Clinical signs
In dairy cattle, the fat cow syndrome occurs within the first few days following parturition and precipitated by parturient hypocalcemia, retained fatal membrane or dystocia. The affected cow does not respond to treatment and become totally anorexic. The cow mat become recumbent and develop a secret form of ketosis, which does not respond to the usual form of therapy. There is marked ketonuria. The affect cow doesn’t eat and gradually become weaker, totally recumbent and die in 7 - 10 days. In cattle with moderately severe fatty liver the clinical finding are much less severe and most cows recover within several days.
DiagnosisThe disease must be differentiated from other diseases like left-sided abomasum displacement, downer cow syndrome and parturition syndrome.
Treatment Cows with fat cow syndrome which are totally anorexic for more than 3 days will die; those which continue to eat (even a small amount) will recover with supportive therapy and nutrition. The parenteral treatment is glucose, calcium and magnesium salts.
175. Nonsurgical collection and nonsurgical transfer of embryos ( T 59 )
the most commonly used equipment for non-surgical embryo transfer in the cow is Cassou AI gun and 0.25 ml French straw. With this equipment, each embryo is loaded into a straw with an air bubble on either side of the fluid containing the embryo itself. The air bubble act as barriers to prevent the indiscriminate movement of the embryos. The recipient is examined for the presence of an appropriate CL and a normal uterus, and an epidural anesthetic is given to eliminate rectal contraction. The straw is loaded into the Cassou syringe, and the sheath is placed over it. The vulvar area is cleaned and wiped dry. The Cassou gun is inserted to the external cervical os, punched through the protective sheath and threaded through the cervix into the uterine horn. A rapid atraumatic placement more caudal in the horn is preferable to a prolonged, difficult placement extremely cranial into the horn. The actual deposition of the fluid and embryo is accomplished with a slow motion similar to that of deposition semen. Advantage of nonsurgical techniques include the reduced amount of time required, the need for little or no special facilities and the reduced cost to the cattle breeder. 176. computer programs for evaluating reproductive performance in dairy herds
individual cow records insemination date (+ name of sire) pregnancy + - calving date milk yield culling medical records + treatment + vaccines body weight
herd management list of cows for insemination (seen in heat, synchronized) list of cows seen in heat (pedometers) list of cows to dry list of cows about to calve list of cows for reproductive examination (pregnancy diagnosis,, repeated breeding) list of cows illness, injury, an-estrus, retained placenta inventory listprograms for evaluating of ratiosdata on milk content (fat, protein )from laboratory
178. surgical collection and surgical transfer of embryos. ( T 59 ) the surgery can be done through a flank approach or the mid-ventral technique. In mid-ventral technique the cow is placed in dorsal recumbence (after general anesthesia ). Incision is made just anterior to the mammary gland into the abdominal cavity. Once the uterus has been located and a suitable corpus luteum has been confirmed in one of the ovaries, a small puncture is made into the lumen of the uterine horn in the same side of the CL. Thee pipette loaded with the embryo is introduced through the puncture and the embryo is deposited. Routine closure and post-operative recover follow. For surgical transfer, the flank approach is used. Palpation of the recipients is used to identify the site of the CL, which must correspond with the side of the flank incision. Paravertebral and local anesthesia is accomplished with a local anesthesia. Routine opening is accomplished, and the site of the CL is confirmed. The uterine horn is grasped and gently retracted to the incision. Transfer is similar to that in the mid-ventral approach, and closure is as usual.
