Mare Infertility

June has arrived, and the beloved mare that you have been trying to get in foal since March is still not pregnant. How do you find out what is wrong and what to do about it? Equine reproduction is an area that has advanced greatly in the last few years. As a result, we are able to solve problems that until a few years ago weren’t even recognized.

The first step toward fixing any problem, is determining what that problem is. For mare infertility this is done through a breeding soundness exam. A breeding soundness exam should include a discussion of the mare’s breeding history, an ultrasound of the uterus and ovaries, a culture and biopsy of the uterus, and possibly uterine cytology. This exam is most effective when the mare is in heat. So to gain the best results, try to have your mare examined when she is in heat.

After your veterinarian has gotten the results of the breeding soundness exam, she or he will be better able to develop a plan for treating the problem. This will also let your veterinarian judge what the cost will be for the treatment, so that you can decide whether the value of the foal justifies the expense.

So what are the most common infertility problems that are faced by mares and their owners? The biggest difficulties are uterine infections and inability of the uterus to eliminate inflammation. In older mares (10 or older) or mares that have had several foals, the cervix (the entrance into the uterus) may be too relaxed and allow infection in. In addition, these mares’ uterus may not be able to drain the fluid that normally accumulates before or after breeding. This fluid, inflammation, and infection are deadly to both sperm and the fertilized egg. To treat these problems the uterus is commonly lavaged or flushed with sterile saline. This cleans or washes the harmful inflammation and infection out of the uterus. By performing this procedure before and up to 2 days after ovulation, we greatly increase the ability of the sperm and egg to survive. This increases our odds of obtaining a pregnancy.