Horse Health

Draft Horse Gestation & Foaling

Gail Damerow and Jackie Clay
The normal gestation period of a pregnant mare is about 340 days, give or take ten days.

If the mare is due to foal in warm weather, she will likely foal on the early side. If she is due to foal in cold weather, she will likely carry a little longer. Since the mare's age and the number of foals she's carrying also influence her due date, a mare may foal early or late regardless of the time of year. It pays to start keeping an eye on your mare at least 10 days before she is due to foal.

The easiest way to calculate the due date is to subtract 25 days from the breeding date. If, for example, the mare is bred in February 27, she will be due to foal approximately on February 2 of the following year.

Mating & Gestation Stats
Proper age at first mating 1 1/2 - 2 years
Period of fertility 10-12 years
Average estral cycle (including heat)

21 days

Range 10-37 days
Average length of heat 5-6 days
range 2-11 days
Usual Ovulation 24-48 hours before estrus ends
Cycle returns, if not breed 21 days
Average gestation 340 days
Range 310-370 days

Signs that the mare is close to foaling include:

Milk veins (the veins under her belly, just in front of the udder) grow large and stand out.

Abdomen develops a point at the lowest portion.

Teats become shiny and tight.

Nipples wax up about 24 to 48 hours before the mare foals.

Milk may drip from the nipples when the mare walks.

Vulva enlarges and relaxes.

Tail and hip muscles drop, making the tailhead stick out.

When contractions begin the mare may exhibit the same signs as colic — looking at her abdomen, pawing the ground, lying down, sweating lightly. It's time to keep an eye on her. Bring her into a safe dry lot at the barn or into a large, roomy freshly bedded box stall. The foal is about to be born. rh horse logo

Jackie Clay was a regular contributor to Rural Heritage. This article appeared in magazine. Gail Damerow a the former editor. Comprehensive information on mares and foaling can be found in Complete Foaling Manual.

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