Every winter, horse breeders try everything to give Mother Nature a little extra push in the right direction. Keeping maiden and barren mares under lights, feeding them a bit extra, stable managers try to fool these mares into thinking it was nearing spring and breeding season.
Timing is the key at thoroughbred nurseries, because all thoroughbreds celebrate their birthdays on January first. Getting mares pregnant as early as possible is one of the keys to success.
Amateur breeders don’t have quite the same tight timeline, but no matter if the mare is a thoroughbred brood mare or a pleasure horse on the family farm, successful breeding takes more than letting nature takes its course. Listening to the pros can give some good advice.
Even when you do all the tricks to help get your mares ‘in the mood,’ many still will not get pregnant early. Still, starting the breeding program early does have some advantages. Mares will need a negative uterine culture before they go to the breeding farm, and veterinarians will want to take that culture when she is in season. Keeping an eye on the mare early allows you to get that taken care of before going to the breeding farm, so you don’t miss out on any breeding cycles. Not only do missed cycles cost money, they also reduce the chances of the mare getting pregnant, especially if she is a maiden.
On professional breeding farms, barren and maiden mares begin the new year with daily visits to the teaser. This is incredibly helpful in determining the mare’s breeding status and determining if she is in season. Even without this help, you can often determine when your mare is coming into season.
Owners who know their mares well will notice when she becomes a little sulky at the start of her season. Also, mares will usually show heat to other horses when they are turned out together. Any time the mare is exposed to another horse, keep your eyes open and you might detect useful signs.
Especially with young maidens, mares who are coming in will usually urinate more frequently, and the urine will be thicker. Mares will also occasionally show a lower appetite than usual.
Your veterinarian can also help give your mare a little push in the right direction. Putting the mare on a ten-day course of progesterone followed with a shot of prostaglandin can help bring her into season. However, you should wait until they have cycled at least once so that the prostaglandin can work on a corpus luteum (an old ovarian follicle) and get the maximum benefit of the treatment.
Your veterinarian will play an important role in helping your mare to get with foal, whether she goes to stay at the breeding farm, is only shipped in for breeding and then brought home, and especially if she is artificially inseminated. Your vet will determine if she is in season, whether or not ovulation is imminent, and any additional assistance that might be required after breeding.
The vet can rectally palpate the mare two days after breeding to see if she has ovulated. If she hasn’t, you will need to return her to the breeding farm. If she has ovulated, the vet might recommend suturing her. Five days after breeding, the vet can check her blood progesterone levels. After eighteen days, tease her if you can to determine if she is in season. If not, the vet can palpate her again.
Pregnancy can be checked by ultrasound. If she is carrying twins, the vet might attempt to abort one fetus at this early stage to reduce the risk of miscarriage and complications. The heartbeat should be visible on the twenty-sixth day after breeding, and the vet will sometimes ultrasound again to check.
Also, blood tests at eighteen days can determine if the mare is pregnant. This is especially important for maiden mares without any pregnancy history to refer to. If the test indicates a need, the mare can begin taking supplemental progesterone at this time. However, oral synthetic progesterone supplements are expensive. One brand, Regumate, could cost between six and seven hundred dollars over the course of the mare’s pregnancy. If it is needed, vets generally recommend a one hundred fifty day course. Some breeders continue the supplementation all the way to term, but there is no evidence that the additional supplementation is helpful.
During the first and second trimesters, weight maintenance is generally the only extra consideration that a pregnant mare requires. An increase in feed is required in the last trimester, because the foal gains sixty-five percent of its overall growth in just this last trimester. Keeping the mare on her usual exercise regimen does no harm and may do a lot of good, at least during the first two trimesters. However, use common sense with any exercise program.
No matter what, making things as clear and easy as possible for the breeding farm makes sure that you get the most for your money and helps to eliminate mistakes. Give them all the information you can, from teasing charts to veterinary information to shot records. Make sure that your mare is de-wormed and has had her hooves trimmed if she is going to stay at the breeding farm for any amount of time. Also, make sure you send her with a good quality halter and, preferably, a neck collar with a name tag. And even if you plan to take her back home right away, make sure to remove her back shoes.
All these considerations will prevent mistakes and give you the best chance of being rewarded with a foal three hundred days from now.