Breeding the Older Mare

The ultimate goal of every breeder is for each mare to produce one live foal each year. However, as in most species, reproductive efficiency declines with age. By the time a broodmare enters her late teens and early 20s her ability to reproduce begins to diminish, and getting and keeping her pregnant become more problematic. Older mares have about a 30 percent chance of becoming pregnant and need to be bred twice as often as younger mares.

The most likely causes of reproductive difficulties in the older mare include poor uterine clearance, anatomical defects involving the reproductive tract, contamination, infection, aged eggs, overzealous use of antibiotics, cysts, ill health, lack of fitness and poor nutrition. Your veterinarian will need to make an accurate diagnosis of the cause of infertility in order to administer a therapy most likely to produce optimum results.

Testing, Testing

According to John Dascanio, VMD, Virginia-Maryland Regional College of Veterinary Medicine, a reproductive examination should start with evaluation of conformation (the uterus could be tilted, for example) and natural barriers that normal keep infection away. You or veterinarian should also examine the reproductive tract by palpation and by ultrasound examination. Following that, your veterinarian should examine the vagina and cervix with a vaginal speculum and manual exam. This may be followed by a uterine culture, cytology (microscopic study of cells) and biopsy, which can help predict the mare's chances of getting pregnant.

Should preliminary results turn up normal, other specialized tests can be performed. Your veterinarian may want to examine the oviduct (the passage through which the eggs move toward the uterus) to make sure it is clear. He or she may also want to test for anti-sperm antibodies, assess your mare's hormonal status and check for chromosomal abnormalities. These procedures may require special equipment or facilities and may not be done on the farm. Diagnostic information can even be gained from frequent ultrasound examinations, such as looking for fluid accumulation with the first day post breeding to help diagnose uterine clearance problems.


Treatments vary from simple to high-tech.

Common Sense Techniques

Good management and sensible, careful breeding techniques can also go a long way to improving the older mare's chances of pregnancy. Here are a few tips: