Identification of measures predictive of age at first puberty
Kody L. Graves, Bethany Mordhorst, Nicole Oldfather, Elane C. Wright,
Benjamin Hale, Aileen F. Keating, Ken Stalder, Jason W. Ross
What is the importance of age of first puberty?
• Impacts the profitability of a swine enterprise.
• Gilts that demonstrate puberty early have less non-productive days than those that demonstrate first estrus late. (Patterson et al., 2010)
• Heavier gilts at first breeding remain heavier compared to lighter counterparts at first breeding. (Rozeboom et al., 1996)
• Age at first puberty is an indicators of lifetime productivity.
• Lifetime productivity lacks heritability and can be influenced by environment.
Age of Puberty Impacts Fallout
Patterson et al., 2010 J. Anim Science
Figure 27.19
Hypothalamus
Late follicular andluteal phases
1
1
2 2
2
3
4
5
5
6
8
8
7 Slightlyelevated estrogen and rising inhibin levels.
Positivefeedback exerted by large inestrogen output.
Mature follicleCorpus luteum
Ovulatedsecondaryoocyte
Rupturedfollicle
LH surgeProgesteroneEstrogenInhibin
Hypothalamus
Early and midfollicular phases
Travels viaportal blood
Granulosacells
Inhibin
Androgens
Convertandrogens toestrogens
Thecalcells
Anterior pituitary
GnRH
FSH LH
The Hypothalamic Pituitary Gonadal Axis
Kiss1 is the Ligand for GPR54
Roa and Tena-Sempere, 2010
A proposed model linking energy balance and the initial GnRH pulsatile secretions responsible for puberty onset.
Figure 1 Serum concentrations of LH and FSH (means±s.e.m.) for prepubertal gilts receiving i.c.v. infusion of saline or either 10 or 100 μg kisspeptin (Kiss).
Lents C A et al. Reproduction 2008;135:879-887
© 2008 Society for Reproduction and Fertility
Variation in Prepubertal Follicular Development
Day 98 ± 4 days
N = 21 N = 27
Ross, Keating and Baumgard, unpublished.
Hypothesis
• Gilts that demonstrate follicular activity earliest will achieve puberty earliest. Additionally, these gilts will be phenotypically distinct in at least one physiological parameter.
Objectives
• To identify a specific time when a cohort of gilts demonstrate variability with regard to follicular development.
• To determine the feasibility measuring parameters related to follicular development during prepubertal development.– Trans-abdominal ultrasound– Vulva development– Serum estradiol– Body weight
• To determine if those factors have any relationship with age of puberty.
Experimental Design
• 155 Gilts ± 2 days of age• On Days 75, 85, 95, 105, 115 of age:
– Body weight– Ultrasound (trans-abdominal)– Measure vulva width, vulva length– Blood draw– Sacrificed 10 gilts
• Recorded follicular development• Uterine weight
Experimental Design
• Remaining 105 Gilts– Heat checked daily– Beginning at 129 days of age– Ending at 200 days of age
• Determine association between phenotypes on days 75, 85, 95, 105, and 115 and age of first estrus.
Body weight gain during prepubertal gilt development
75 85 95 105 1150
102030405060708090
Body
Wei
ght (
Kg)
Day of Age
Change in vulva length during prepubertal development
75 85 95 105 1150
5
10
15
20
25
30
35
40
Day of Age
Mill
imet
ers
75 85 95 105 1150
5
10
15
20
25
30
35
Change in vulva width during prepubertal development
Day of Age
Mill
imet
ers
75 85 95 105 1150
200400600800
100012001400
Day of Age
Mill
imet
ers2
Change in vulva area during prepubertal development
Prepubertal Follicle Development
75 85 95 105 1150
2
4
6
8
10
12
No Follicle develoment
< 10 small follicles
10->100 small follicles
Freq
uenc
y
Day of Age
Uterine Weight of Gilts Sacrificed during Prepubertal Development
75 85 95 105 1150
10
20
30
40
50
60
ab
bc
c
d
dDay Effect P < 0.001
Ute
rine
Wei
ght (
gram
s)
Day of Age
Distribution of Age of First Estrus
140-145
146-150
151-155
156-160
161-165
166-170
171-175
176-180
181-185
186-190
191-195
196-200
> 2000
5
10
15
20
25
30
Day of Age
Freq
uenc
y
75 85 95 105 1150
102030405060708090
Estrus
No Estrus
χ2 = .75 .57 .61 .78 .65
Body weight association with puberty by 200 days
Kilo
gram
s
Day of Age
135 155 175 19525
30
35
40
45
50
55r = -0.217P =0.055
Body weight at Day 75 is correlated to age at first estrus
Day
75
body
wei
ght (
Kg)
Age of First Estrus
135 155 175 19530354045505560 r = -0.136
P = 0.23
Body weight at Day 85 lacks correlation to age at first estrus
Age of First Estrus
Day
85
body
wei
ght (
Kg)
135 155 175 19540455055606570 r = -0.141
P = 0.22
Body weight at Day 95 lacks correlation to age at first estrus
Age of First Estrus
Day
95
body
wei
ght (
Kg)
135 155 175 19550556065707580 r = -0.068
P = 0.55
Body weight at Day 105 lacks correlation to age at first estrus
Age of First Estrus
Day
105
bod
y w
eigh
t (Kg
)
135 155 175 19560657075808590 r = -0.102
P = 0.37
Body weight at Day 115 lacks correlation to age at first estrus
Age of First Estrus
Day
115
bod
y w
eigh
t (Kg
)
Top Quartile
Middle Two
Quartiles
Bottom Quartile
Top Quartile
Middle Two
Quartiles
Bottom Quartile
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
77%
60%
46%
69%
60%54%
85%
72% 73%77% 77%
69%180
200
Relationship between body weight on days 75 and 115 and puberty onset
Day 75 Day 115
Perc
enta
ge
r = -0.217P = 0.055
r = -0.102P = 0.37
75 85 95 105 11505
1015202530354045
EstrusNo Estrus
Vulva Length association with puberty by 200 days
χ2 = .97 .93 .10 .69 .47
Mill
imet
ers
Day of Age
75 85 95 105 1150
5
10
15
20
25
30
35
40EstrusNo Estrus
Vulva Width association with puberty by 200 days
χ2 = .56 .74 .07 .24 .84
Mill
imet
ers
Day of Age
140 150 160 170 180 190 20010
15
20
25
30
35 r = -0.083P = 0.46
Correlation between Vulva Width at Day 75 to age at first estrus
Day
75
Vulv
a W
idth
(mm
)
Age of First Estrus
140 150 160 170 180 190 20010
15
20
25
30
35 r = -0.118P = 0.30
Correlation between Vulva Width at Day 85 to age at first estrus
Age of First Estrus
Day
85
Vulv
a W
idth
(mm
)
140 150 160 170 180 190 20015
20
25
30
35
40r = -0.117P = 0.31
Correlation between Vulva Width at Day 95 to age at first estrus
Age of First Estrus
Day
95
Vulv
a W
idth
(mm
)
140 150 160 170 180 190 20020
25
30
35
40
45 r = -0.20P = 0.07
Correlation between Vulva Width at Day 105 to age at first estrus
Age of First Estrus
Day
105
Vul
va W
idth
(mm
)
140 150 160 170 180 190 20020
25
30
35
40
45 r = -0.28P = 0.01
Correlation between Vulva Width at Day 115 to age at first estrus
Age of First Estrus
Day
115
Vul
va W
idth
(mm
)
Vulva Area association with puberty by 200 days
75 85 95 105 1150
200
400
600
800
1000
1200
1400
Estrus
No Estrus
χ2 = .56 .90 .10 .39 .64
Mill
imet
ers2
Day of Age
140 150 160 170 180 190 200200
400
600
800
1000
1200
1400
r = -0.075P =0.51
Correlation between Vulva Area at Day 75 to age at first estrus
Day
75
Vulv
a Ar
ea (m
m2 )
Age of First Estrus
140 150 160 170 180 190 200200
300
400
500
600
700
800
900
1000
1100
1200 r = -0.065P =0.56
Correlation between Vulva Area at Day 85 to age at first estrus
Age of First Estrus
Day
85
Vulv
a Ar
ea (m
m2 )
140 150 160 170 180 190 200200
400
600
800
1000
1200
1400
1600
1800 r = -0.119P = 0.30
Correlation between Vulva Area at Day 95 to age at first estrus
Age of First Estrus
Day
95
Vulv
a Ar
ea (m
m2 )
140 150 160 170 180 190 2000
200400600800
100012001400160018002000
r = -0.135P = 0.24
Correlation between Vulva Area at Day 105 to age at first estrus
Age of First Estrus
Day
105
Vul
va A
rea
(mm
2 )
140 150 160 170 180 190 2000
200
400
600
800
1000
1200
1400
1600
1800
2000 r = -0.167P = 0.14
Correlation between Vulva Area at Day 115 to age at first estrus
Age of First Estrus
Day
115
Vul
va A
rea
(mm
2 )
75 85 95 105 1150%
10%
20%
30%
40%
50%
60%
70%
< 1 St. Dev. Of Mean
Within or > 1 St. Dev of Mean
Total
Vulva Area association with puberty by 180 days of age
Vulva Area association with puberty by 200 days of age
75 85 95 105 1150%
10%20%30%40%50%60%70%80%90%
< 1 St. Dev. Of Mean
Within or > 1 St. Dev of Mean
Total
Summary and Implications
• These data demonstrate an association between vulva development on day 95 and ability to achieve puberty by 200 days.
• Of those animals that achieved puberty by 200 days:– body weight at day 75 and vulva width at days 105 and 115 were
significantly correlated to age at first estrus.
• These developmental time-points represent specific days in age that observations can be made to distinguish gilts with high and low probability of achieving puberty by 200 days of age.
Questions?
