By Tina L. Lewis
Preparing Your Mare For Breeding
By now you have probably chosen the Stallion you want to breed your mare to this Spring. The stallion you have chosen compliments your mare perfectly in conformation, disposition, pedigree and color and you are so excited you simply cannot wait, not only to get her bred, but for that gorgeous foal next year. Don’t wait. Get started now to insure you not only have a gorgeous foal next year, but that you have a foal next year by preparing your mare for a successful breeding, conception and full term gestation of that foal.
There are so many things to consider with regard to your mare’s health and breeding soundness and, depending upon the weather in your area, when you might want a foal to be born. In order to plan this well we need to first understand the mare’s estrus or “heat” cycle.
During part of the fall and most of the coldest winter months, nature gives the mare a break and she will stop cycling temporarily. This is called anestrus. This is nature’s way of preventing the mare from having a foal at a time of year that would not be favorable for it. Remember that the horse is a herd animal and in a herd environment, it is very hard for a foal to survive during the winter as food is scarce and the herd must move constantly to find feed, and wild animals prey upon the young, especially in the winter when they, themselves are hungry and food is scarce. A foal is an easy target. Spring is the time that a mare will naturally cycle. Depending upon where you live, anestrus can be a short period, or a very long period, as longer days and warmer weather determine its end. The beginning of the estrus cycle is known as proestrus or “transition period”. This is usually when there will be more activity on the ovaries and indicates that the mare is coming into her estrus cycle. The actual “heat” cycle is known as estrus and as estrus increases the mare begins to secrete hormones and will begin to show outward signs of heat, that will include, but not be limited to, squatting, turning her rear to the stallion, urinating (usually more of a milky urine than normal), tail lifting, and winking (rapid open and closing) of the vulva, and will exhibit general interest or attachment to the other horses. This is when the mare is most receptive to the stallion and will ovulate and be capable of conception. The estrus cycle of a mare usually last from 5-7 days.
After the mare ovulates and goes out of estrus, or heat, she goes into a period called diestrus. This is the period between estrus cycles during the Spring and Summer months. It will last until the next estrus cycle begins, about 14 days, for a total of about 21 days in her estrus cycle (give or take a day or two). The cycle of estrus and diestrus will continue all season until fall when the mare will go back into anestrus again for the winter and will no longer be receptive for breeding and will not conceive.
Most stallion owners and Stallion Stations will begin to accept mares about February 1, each year, for the breeding season, and begin their teasing program, but most mares will still be in proestrus or transition until the days get longer and warmer. If you want to breed as early as possible for a January foal you can put your mare under lights for about 90 days in her stall, beginning about November 1. She needs 16 hours of total daylight and it needs to be consistent. Most mare owners put the lights on a timer so they come on about 4 PM before it begins to get dark outside and stay on until about 11 PM or as many hours as necessary to reach 16 hours of daylight in your area. The key here is to have a total of 16 hours of daylight adding artificial light at the end of the day. Check your Time Zone for your local daylight hours and adjust your timer or schedule of turning on the lights in your barn accordingly. Remember, you should be able to easily read a newspaper in the darkest corner of her stall for the lights to be bright enough to simulate daylight and be successful in tricking her body into believing that it is Springtime and she should begin to cycle.
If you are going to allow your mare to cycle naturally then you can plan on about the first of March or, if she is in foal, you will need to plan according to her due date. Some mare owners like to catch the foal heat particularly if the mare is due to foal late in the season as this will move you up about 10 days to 2 weeks for foaling next year. The foal heat, unfortunately is very short, about 3 days or so, and it is tougher to get the mare in foal on this heat for this, and other reasons. You may want to opt for breeding her on her next heat for a better chance of getting her in foal, especially if you are shipping cooled semen or utilizing frozen semen. This heat cycle is usually about 30 days after her foal is born.
The body condition of your mare is also key in the success of getting her in foal. Your mare should not be too thin or too fat as both of these can cause your mares cycle to be slightly off or inactive and make conception difficult and even impossible. Monitor her weight and be sure she is free of parasites, on a good deworming schedule and fully vaccinated and up to date on all of these before taking her to be bred. Her teeth may also need floating to ensure she is getting the nutrition needed to keep weight on. You will also want to have her on a diet appropriate for her age and activity so as not to cause her to drop weight when it is so badly needed to keep her body condition in check and prepared for breeding, carrying a foal for over 11 months, delivering and nursing.
Lastly, an important step on the road to getting your mare in foal is a breeding soundness exam. It is crucial and should include a uterine culture. Many mare owners, understandably, try to cut a few corners here and there but this is not one that should be cut. It may cost you more time and more money in the long run. Typically, most breeding contracts require a current negative uterine culture and a breeding soundness exam and there are two important reasons why. If the mare is infected, she will not get pregnant and it will be a waste of everyone’s time and your money to continue to breed her live cover, artificially inseminate her or ship semen to her. These costs add up quickly. The stallion owner has a limited amount of semen, even with a live stallion as a stallion can only produce so much semen and the energy it takes to get a mare bred. It is a waste of time as well as stallion energy to collect and ship it to or breed to those mares who cannot conceive due to infection or breeding unsoundness. It also makes the stallion’s conception rate seem low, when, in fact, it is the mare who is responsible because she is unable to conceive in poor condition or with bacteria in her uterus. In addition, if the mare’s uterus is just slightly infected, she may get in foal. However, keep in mind that when the mare conceives, her cervix closes tightly to protect the fetus. It is like a steel door. Anything that has not been removed is trapped. This means that any bacteria that may have been present when she conceived, is in the uterus with your maturing foal. The chances of her aborting are greatly increased. The bacteria will continue to grow and, at some point, it will affect the maturing foal. To increase your chances of a live, healthy foal, the mare’s uterus needs to be healthy. Remember, achieving pregnancy is only one aspect of the breeding process, getting to term is quite another. There are many cases where mares were only slightly infected and were bred anyway. These mares conceive, only to abort the foal later in the pregnancy, too late to rebreed that year and all that time and money is lost forever. Taking the time to “clean up” the mare and insure she is breeding sound is an important and extremely cost effective aspect of the breeding process, whether she is being bred via live cover, artificial insemination or cooled shipped semen from across the country. You want to know your mare is clean and breeding sound and can conceive when she is bred, and so does the stallion owner. Most Stallion Stations and stallion owners have their stallion’s semen tested for concentration, progressive motility, morbidity as well as freezing/shipping ability to ensure they can, and will, impregnate your mare if she is breeding sound. These stallions are also capable of, and usually have, many foals on the ground to further prove their fertility as they can have many foals a year where a mare can only have the one with many more factors affecting her fertility each year. If your mare, for instance, had retained a placenta, even briefly, her last foal or was Artificially Inseminated unsuccessfully last year or lost a foal mid pregnancy. She is high risk for bacteria in her uterus and should be cultured before trying to breed her again. If you do not culture your mare and she does not get in foal right away or loses the foal mid pregnancy, this might be something to consider and a breeding soundness exam with a negative uterine culture would be advised before trying again.
