Normal parturition process in large animals

(bovine and equine)M.Waseem

DVM, UCV&As, IUB

Why to study

normal process?

To understand the time of

calving

To assistance in calving

To understand

the dystocia

Parturition

Give birth to young one

Possible factors that induces parturition

Increases in fetal size

Fatty degeneration of placenta

Physiological factors Increased co2

in maternal blood due to fetal activity

Release of fetal antigen serotonin

Biochemical factors

ParturitionPhysiological factors

Biochemical factorsHypothalamus Anterior

PituitaryAdrenal Cortex

CRH ACTH

Fetal Corticosteroids(Cortisol)

Lung(surfactant)

Liver(glycogen)

Thyroid(metabolism)

Progesterone Estrogen PGF2a

UterineContractions

Relaxin

Oxytocin

Uterine Endometrium» Oxytocin receptors

Ovary(CL)

CLRegression

Pelvic ligament stretching

placenta

enzymes

17-alpha hydroxylase

aromatase17-20 dismolase

Enzymes converting P4 to E2

Final Role of OxytocinSensory Neurons in Cervix

Oxytocin fromPosterior Pituitary

MyometrialContractions

Signs of labor

changes in body temperature

enlargement of the vulva

relaxation of the sacro-sciatic

ligaments

dilation of the cervix.

changes in quantity and viscosity of vaginal

secretions

udder changes including enlargement, tenseness and filling of the teats

Process of parturition consists of 3 stages

stages

Stage 1: Cervical dilation

Stage 3: Expulsion of the placenta

Stage 2: Delivery of the fetus

Stage 1 signs

The pastured cow will usually seek an isolated

place.

Restlessness ,lie down and get up

frequently

Occasionally, she will kick at her belly and wring her tail.

The cow (particularly first-calf heifers) will

show signs of uneasiness and

pain.

Vaginal discharges increase

Stage 2 signs

cervix is fully dilated.

plus fetal parts enter the birth canal

second water sac (amniotic sac)

Normalp.p.p

presentation

position

posture

Anterior longitudinal

Dorsal or dorsosacral

extended

Expulsion of fetal

membranes

3rd stage