The best time to breed a mare is in the spring. This is the time of year she is most fertile. In the spring, heat cycles are more regular and more evident and the mare is more likely to conceive.
Heat cycles usually recur at 21-day intervals. However, these intervals may be as short as 10 days or as long as 37 days. The actual heat period usually is from 4 to 6 days, but it may range from 1 to 37 days.
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Signs that a mare is in heat are relaxation of the external genitals, more frequent urination, teasing of other mares, restlessness, and an apparent desire for company. There also may be a discharge from the vagina.
If you have a young, shy mare, present her to the teaser stallion fairly often as the breeding season approaches. This will acquaint her with the breeding procedure.
Since actual ovulation probably takes place toward the end of the heat period, you should mate the mare every day or every other day beginning with the third day after she first comes into heat Fillies usually start coming into heat when they are 12 to 15 months old.
However, most horsemen do not breed fillies until they are 3 years old so they will not foal until they are 4. Broodmares that are properly cared for may produce regularly until they are 25 years old or older.
When you select a mare for breeding, get one that is 3 or 4 years old if possible. If you select an older mare, make certain her breeding habits are regular and normal.
The gestation period of horses is about 336 days, or 11 months. This period may vary as much as 20 to 30 days with individual mares.
The first sign of approaching parturition may be a distended udder 2 to 6 weeks before foaling time. About a week before foaling, the muscular area around the base of the tail usually shrinks and the vulva becomes full and loose.
The teats usually fill out to the ends about 4 to 6 days before foaling. As parturition draws near, milk may drop from the teats. Do not milk the mare at this time.
If the weather is warm and dry, the ideal place for foaling is in a clean pasture away from other livestock.
If a stall is used, it should be at least 12 feet square; have a smooth, well-packed clay floor; be free of feed containers and other obstructions ; and be away from occupied stalls if possible.
As soon as the foal is born, treat its navel cord with tincture of iodine to reduce the danger of navel infection. A strong, healthy foal will be on its feet and ready to nurse in one-half to 2 hours.
Make sure the foal gets the colostrum, or ñrst milk. This milk contains antibodies that protect the foal temporarily against certain infections, and it also serves as a mild laxative.
Always watch the mare closely for any sign of trouble before, during, and after foaling. If you suspect trouble, call a veterinarian at once.
Mares usually come back into heat 7 to 11 days after foaling (foal heat), but the time can range from 3 to 13 days. Some horsemen rebreed mares during this first heat after foaling, usually on the eighth or ninth day, providing the birth was normal and the mare suffered no injury or infection. However, other horsemen prefer to rebreed ïïiares during the heat period that follows the foal heat, which is from 25 to 30 days after foaling.