Parturition and Postpartum Period in Livestock: Hormonal, Stages, and Management

What initiates parturition?

Parturition is initiated by the fetus as the fetal hypothalamus matures.

What hormonal changes occur during parturition?

Low progesterone, high estrogen, high oxytocin, high PGF2 alpha, and high relaxin.

What are the signs of impending parturition?

Udder fills with milk, relaxation around tail head/flank, nesting behavior, isolation, off feed, colic/discomfort.

What happens during Stage 1 of parturition?

Uterine contractions become regular, the fetus rotates into position, and the cervix dilates.

What occurs during Stage 2 of parturition?

Water breaks, the fetus passes through the birth canal, and the umbilical cord breaks.

What is involved in Stage 3 of parturition?

The placenta detaches and is expelled.

What is the normal length of Stage 1 parturition in cows?

2-6 hours.

What is the normal length of Stage 2 parturition in sows?

150-180 minutes.

What are common causes of dystocia?

Small dam, first-calf heifers, oversized fetus, genetics, prolonged gestation, fetal malpresentation.

How is parturition induced in sows?

PGF2 alpha after day 112; before day 110 causes abortion.

What is puerperium?

The period when the uterus returns to normal size and condition after parturition.

What is the typical time for uterine involution in dairy cattle?

40-50 days.

What factors affect the return to estrus?

Milk suckling intensity, nutrition, parity, age, metabolism, and season.

What is the rebreeding goal for cows?

1 calf per year; breed back within 90 days.

What is the gestation length for ewes?

150 days.

What is the typical uterine involution time for mares?

21-28 days.

What is the impact of suckling on postpartum anestrus?

Suckling delays the return to estrous cycles by reducing GnRH/LH pulse activity.

What is the goal for rebreeding sows?

24 pigs per year per sow; wean at 18-21 days.

What hormonal changes trigger parturition?

Fetal cortisol increases estrogen and decreases progesterone, promoting uterine contractions.

What is the role of relaxin during parturition?

Relaxin helps with cervical dilation and pelvic relaxation.

What occurs during the delivery of membranes?

Chorionic villi detach and afterbirth is shed.

What is the typical postpartum interval for beef cattle to resume ovarian activity?

50-60 days.

What is the typical postpartum interval for sows to resume ovarian activity?

About 7 days.

What is the effect of nutrition on postpartum recovery?

Negative energy balance can delay return to estrus.

What is the significance of the fetal hypothalamus in parturition?

It releases CRH/CRF, stimulating ACTH release and initiating parturition.

What is the role of PGF2 alpha in inducing parturition in cows?

It can be administered before day 150 to induce parturition.

What is the typical length of Stage 3 parturition in mares?

About 1 hour.

What is the typical postpartum interval for ewes to resume ovarian activity?

About 180 days, depending on the season.