Featured Article (December 2002)

5 Things Every Mare Owner Should Know About Long Distance Breeding

It is popular among horse owners today to book their mare to a stallion

a long distance from home using transported semen by artificial insemination (TAI). The reasons include safety for the mare, reduced risk of infectious disease transmission, and potentially reduced cost. This breeding alternative exists for most breeds. However, the mare owner should understand the inconveniences associated with keeping the mare at home for breeding. These include negotiating the breeding contract, communication with the stallion owner or manager to arrange semen collection and shipment, monitoring the mare's estrous cycle, frequent visits by the local veterinarian to determine readiness to breed, and early pregnancy diagnosis.

1. Communication between Stallion and Mare Owners

Communication needs to start early between mare and stallion owners. This involves contract negotiation in advance so that each party knows their respective responsibilities. The mare owner may need to pay for some or all of the transport-related expenses. These include purchase of, or a security deposit on, the semen shipment container, fees for each semen collection, and air or overnight-courier costs. The breeding fee may need to be paid in full in advance, or once the mare is declared in foal, or at the birth of a live foal, or there may be a set fee for each semen collection. There are few standards. Each stallion owner may have a different breeding management scheme.

Most stallions with excellent conception rate on their own farm have similar success with TAI, but not always! Ask the stallion owner to provide some information on the stallion you intend to use. You should expect a 60% conception rate per cycle for semen from a good "shipping stallion." It is a very good idea to make sure the stallion has been determined venereal-disease free. He should also be negative on serological testing to Equine Arteritis Virus (EAV).

2. Shipping Schedule

The stallion owner or farm manager may only collect semen on certain days of the week. Such limitations on availability of semen must be considered. The stallion may be a show or performance horse, and he may not be available for semen collection during certain days or weeks of the upcoming season. What seems like a convenience to the mare owner can easily become a coordinating conundrum.

3. Monitoring the Mare's Estrous Cycle

Documenting a mare's estrous cycles without a stallion to tease with on the mare's farm presents challenges of its own. Some mares will show signs of heat by changes in behavior that observant owners can identify. Some mares may also show interest in another mare, or a gelding. But, most commonly, the signs of heat are not evident to the inexperienced observer, and sometimes not even to the well-trained eye! The mare will, therefore, have to be examined internally for follicle development or be synchronized using hormones to prepare her for breeding on a specific date (or dates).

4. Readiness to Breed

Rectal palpation and ultrasound exams for staging the mare's estrous cycle and determining ovarian follicle development are a must. The investment in breeding fees, transportation costs, and the time and effort to arrange semen shipment schedules require it. At the bare minimum a cytology sample of the mare's uterus should be examined to screen for presence of inflammatory cells, which may indicate a uterine infection. Further pre-breeding diagnostics may also include a uterine culture and biopsy. Discuss these with your veterinarian.

Appropriate timing of TAI is very important. The goal is to predict the mare's ovulation in advance of its actual occurrence by at least 48 hours, and not later than 96 hours. This gives the stallion owner time to arrange a semen collection, and meet transportation schedules to allow timely arrival of the shipment. The TAI procedure is relatively routine and requires no special equipment.

5. Early Pregnancy Diagnosis

The final step is an early pregnancy diagnosis by ultrasound between 14-17 days after the mare's ovulation. Other benefits of this exam include detecting the conception of twins, and if the mare did not conceive, another estrous cycle has not been missed. She may be ready to breed again in a few days, starting the process all over. However, most mares bred by TAI to an otherwise "good shipping" stallion will conceive in less than three attempts.

Further information on this and other breeding topics can be found at Dr. Ley's website. Dr. Ley is a board certified specialist in equine reproduction and has authored multiple scientific journal articles and book chapters. He was formerly a professor of equine reproduction at both Virginia Tech in Blacksburg and Oklahoma State University in Stillwater, OK. Dr. Ley is currently in private veterinary practice at REACH, LLC on Long Branch Farm near Millwood, VA.