Breeding Horses

Breeding Horses

Horse breeding is a multi-million dollar international industry. For purebred horses, careful selection of the stallion and mare is essential to successful breeding. From conception to foaling, horse breeding today is carefully managed through modern technology. Whether you are breeding horses for racing, show competition or the family farm, a firm understanding of the breeding and foaling process will ensure a successful outcome. At Western Prairie Equine Service, we offer services for preparing your mare for natural breeding or managing artificial insemination with fresh, fresh cooled or frozen semen (including deep horn insemination). 

Equine Reproduction

While wild horses typically breed and foal in mid to late spring, domesticated breed for competition requires horses to be foaled as close to January 1st as possible for maximum competitive advantage in the Northern Hemisphere. To help stimulate the ovulation process during winter, you may elect to keep your mare under barn lights to mimic a longer day. A mare signals that ovulation is close, "in heat",  by urinating in presence of another horse, squealing, winking the vulva, and raising her tail to reveal the vulva.

Once an egg is fertilized, it will remain in the oviduct for 5-6 days before descending into the uterus; fixation will occur on day 16. By day 15, the embryo will be visible on a trans-rectal ultrasound, with a heartbeat detectable by day 23. The placenta will form around day 40 to 45 of pregnancy. The sex can be determined using ultrasound on day 65. The entire gestation process is approximately 11 months. 

Advanced planning will make the foaling process go as easily as possible for both you and your mare. While most mares can handle foaling on their own, it is best for you to have your veterinarian on alert in order to offer assistance if needed. While the majority of mares will foal 330 to 340 days from breeding, some may foal as early as 320 days. Mares should be immunized four weeks in advance of foaling with vaccines specifically approved for pregnant mares. These vaccines will stimulate the mare to produce antibodies, which will be passed to the foal in the mare’s colostrum.

Prior to foaling, prepare a foaling stall. Foaling happens quickly once it begins, so closely monitor your mare in the days leading up to the expected foaling date is crucial. Wrapping the mare’s tail will keep the area clean and easier to observe. Following foaling, a mare will lick the foal to clean it and stimulate circulation. A new foal should be able to stand and get milk from its mother within a few hours of birth.

If you are considering breeding your horses, feel free to contact Dr. Harris to learn more about what to expect and how best to prepare.



Contact Us

Get in Touch


Find us on the map


Monday - Friday:

8:30 AM - 5:00 PM


By Appointment


Emergency Services Available