William Moyer, DVM, department head of large animal clinical sciences, College of Veterinary Medicine at Texas A&M University, answers this month's equine health question.
Q - I have decided to breed my eight-year-old Quarter Horse mare. I am wondering if there are measures I should take prior to the breeding season to enhance the likelihood of pregnancy.
A - Your question is an excellent one and timely. Fall is an ideal time to begin preparing the mare and planning for the breeding season.
First and foremost, ensure that the mare is in the best of general health. It's not unusual to be faced with trying to solve health problems prior to the breeding season. This can involve chronic lameness problems, which may cause a problem in carrying or delivering the foal. Overweight or underweight mares are not ideal candidates. Less than ideal body condition can negatively affect fertility and the ability to carry, deliver and sustain a nursing foal. There can also be problems with the reproductive tract.
The first consideration would be to have the mare examined by a veterinarian familiar with equine reproduction, whether the mare is a first-time breeder or an experienced broodmare. The age and experience of the mare plays a role in what the examination will involve. The first-time breeder, or maiden mare, under the age of eight years should be examined to ensure that the reproductive organs are intact and functional. This involves a transrectal examination and ultrasound of the reproductive tract and ovaries. A visual examination also is performed that includes the vulvar, vaginal, and cervical regions of the tract. This is done with a speculum. Although many breeding farms still require them, uterine cultures to detect bacterial infection is usually not necessary in maiden mares unless other aspects of the examination indicate a problem. Older maiden mares benefit from a uterine biopsy. This procedure is low in risk. It consists of taking a small piece of tissue from the uterine lining. A uterine biopsy is probably the single most informative procedure regarding a mare's ability to become pregnant and carry a foal to term. One reason is that older maiden mares, as opposed to mares that are pregnant year after year, can demonstrate evidence of age-related uterine problems that can't be detected by any other means. It then follows that the older the mare, the more valuable this examination procedure. Also, experienced broodmares may profit from an intrauterine bacterial culture. The examination should also include a general physical examination that includes dental health and status combined with an accurate history (medical and surgical) and an assessment of body condition.
The vaccination status of the individual should also be assessed. If the mare is sent off the farm or ranch to be bred, she can be exposed to horses that may be bringing disease to the farm. Most breeding operations, especially if crossing state lines, will require a recent Coggins test.
The suggested list of vaccines includes: Eastern and Western Encephalitis, West Nile Encephalitis, tetanus, rabies, equine flu and rhinopneumonitis. Vaccinate the mare at least two weeks prior to transport to allow adequate time for protective antibody titers to develop. These are decisions that can be facilitated by the examining veterinarian or the breeding operation that you've chosen to use.
Another consideration which is often overlooked is mares that have recently been in athletic competition or recently retired. Most equine reproductive experts are of the opinion that it's best to provide some time away from competition before the actual breeding season. This allows the mare to settle into normal heat cycles as well as allowing "withdrawal" of drugs, especially various forms of anabolic steroids, that may have been used. Unfortunately, the use of various forms of medication to enhance performance or allow horses to compete with problems is not unusual. Many of these drugs can have a negative effect on reproductive performance.
The time away from competition, in my opinion, also allows the individual horse to relax and live a more normal life. It is also useful to provide the breeder with an objective appreciation of the mare's behavior. This will greatly facilitate the process as well as lower the risk of injury to the mare and the stallion if live cover is to be used, and the handlers. Misbehaving mares can often - but not always - be managed by experienced handlers. But allowing them to find that out the first time they go to tease or breed the mare is really putting everybody at risk.
Other options include doing nothing and shipping her off, breeding her at home or using artificial insemination. Thus the decision may well be influenced by economics. I personally believe a reproductive and general physical examination is money well spent as repetitive trips or keeping the mare at a breeding operation can be expensive, and there are no guarantees that a successful breeding will take place. One's odds, however, are improved by knowing the health and reproductive status of the mare before the actual act.
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