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Foal Heat Breeding...
BREEDING THE FOALING MARE
This week we will discuss breeding the mare that foaled this spring. One commonly accepted practice in the horse world is breeding on what is called foal heat. Most of our mammals and certainly the horse will have the first ovulation after foaling in about one half the time of a normal heat cycle. The ovaries have been resting thru most of pregnancy. Once the mare foals, the ovaries are stimulated to start cycling. They start from a stage similar to being one half way through a normal heat cycle. So it is only about ten days until the ovulation. Actually, this can vary: during this year I’ve seen foal heat range from five days to sixteen days.
When we actually think about it, the possibility the mare will breed on foal heat is pretty amazing. It has been only ten days since she delivered over 150 pound of foal, placental tissue, and the fluids that surround the foal! The uterus is frantically trying to evacuate itself so it can clean up the residue. It is doing this by contracting the muscles in the walls, directing the contents toward the cervix and outside. This is why the mare will often lay down and even roll on the day of and after foaling. These uterine contractions are strong and cause considerable discomfort.
The mare that passes the tenth day without showing signs of heat can be confusing to us. Almost all of these will have a normal follicle upon exam. They are physiologically in heat but are not psychologically receptive. This is because of the presence of the new foal and the mother’s concern for its safety in the presence of the screaming, charging stallion. While we normally discourage its use, some restraint may be necessary to accomplish a breeding. This would only be after an examination to determine the ovaries and uterus were showing signs of heat.
We do have criteria to follow when deciding if the mare should be bred on foal heat:
If the mare had any difficulty foaling, such as a prolonged labor, difficult labor requiring help, or received any injuries during the foaling process, we suggest not breeding on the foal heat.
Also, if the mare retained the placenta for longer than four hours, we suggest waiting.
Another criteria we use when deciding to breed the mare is the expense and trouble involved in getting the mare to the stallion. Breeding on foal heat will result in a pregnancy in fifty percent of the time. If you are taking the mare some distance away, or want to breed her with cooled shipped semen, we suggest passing on the foal heat in favor of the next heat which should give a considerably higher pregnancy rate.
For the mares we are breeding with shipped semen, we suggest flushing the uterus before the foal heat, along about seven days. This will evacuate the uterus and speed its recovery. We then let the mare pass through foal heat. Once foal heat is over, we culture the uterus to be sure there is no infection present. Culturing the uterus before foal heat is sure to find bacteria present as it is almost impossible to have a clean culture at this time. The process of having a heat is a cleansing time as the blood cells responsible for consuming bacteria are rushed into the uterus.
With a clean culture, we will induce a heat with the use of prostaglandin. This not only allows us to bring the mare into heat a week or so earlier than her natural heat, it also allows us to schedule the heat for our convenience in ordering semen or, for a time convenient for delivering the mare to the stallion. This procedure works very well and it should be used even if it is not a “natural” heat.
If all the conditions are met, foal heat breeding can help make next year’s foaling date earlier in the season. If foal heat breeding is being considered, following these guidelines will increase the probablility of success.
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