Page 955 - The Veterinary Care of the Horse

The placenta is normally expelled within 1 hour of the foal being born. The mare may go

down again and experience colicky pain as it is delivered. If the placenta has not been
VetBooks.ir delivered within 3 hours, notify your vet.

Induction of parturition

Mares are rarely induced to foal as the normal gestation period varies from 320 to 360 days.
The foal matures in the last 2–3 days of gestation and there is no 100% reliable method of

determining if this has occurred. Artificial induction before foetal maturation takes place
considerably decreases the foal’s survival chances. The procedure may be considered in:
• mares with prepubic tendon rupture

• cases where foaling problems are anticipated

• cases where the mare or foal is considered to be at risk if the pregnancy continues.

Oxytocin is most commonly used to induce parturition.

Complications of induction include:

• the birth of weak or premature foals

• premature placental separation: a thick red membrane (the allantochorion) appears at the
vulval lips instead of the white amnion (Figure 19.28)

• foaling difficulties

• retained placental membranes.