To determine an optimal breeding window, mares are examined by transrectal palpation and ultrasonography. This may be necessary anywhere from several times per week to several times per day, depending on the mare’s cycle, the insemination method, and the history of the mare.

After breeding, mares are examined for pregnancy approximately 14 days after ovulation. This is an important examination, as any twin follicles will need to be addressed between the 14-17 day period. Twin embryos result in low pregnancy success rates and can be dangerous for the mare and/or foal(s), so it is recommended practice that any secondary/twin follicles be pinched and aborted during this 14-17 day period in order to allow the other embryo to develop regularly.

Artificial Insemination (AI) involves the placement of frozen or cooled semen into the reproductive tract of a mare. This has become commonplace in the equine industry and offers several advantages over live covering.

• No contact between stallion and mare allows a safer environment for both horses and staff
• More collections from the stallion are possible
• Mare cycles can be micromanaged to ensure insemination within 24 hours of ovulation (6 hours for frozen semen)
• Semen may be frozen for use after a stallion’s death or prior to castration
• AI reduces the chances of venereal and non-venereal disease transmission
• Genetics/bloodlines from rare or valuable breeds/stallions are available internationally
• Antibiotics and extenders can effectively improve semen quality and life

When managing a mare to be bred with AI, we keep them at our facility for several days to evaluate follicular growth and quality; determine optimal breeding time; order, evaluate and inseminate the semen; and perform post-breeding treatments such as uterine antibiotic infusions. Medications or hormonal treatments are also used to help target or hasten ovulation, improve chances of conception, and treat conditions or infections in the mare which may prevent proper ovulation or difficulty maintaining an embryo. The chances of success in achieving an artificial insemination pregnancy can be improved significantly through an experienced veterinary team by using good quality semen and a fertile mare.

Delivery of semen can often cause some difficulties for mare owners and staff. As cooled semen is only viable for 24-48 hours after collection, it is often shipped overnight via FedEx or UPS. Deliveries needed on weekends or holidays can prove challenging. Sometimes we may even need to fly semen as cargo by plane and using a courier service, which increases costs.

Most stallions have set breeding seasons and regular scheduled collection days, which must be carefully considered when evaluating future reproduction work.

Frozen Semen

When breeding with frozen semen, which has a shorter lifespan when in the mare’s reproductive tract, it is essential that the mare be inseminated as close to ovulation as possible. Mares are examined for follicular growth every 4-6 hours to accurately predict when the mare will ovulate and inseminate in proper time. Frozen semen is

placed using a technique called deep-horn insemination, where the thawed semen is deposited closer to the site of fertilization than just in the standard uterine body.

Although fresh/cooled semen tends to provide a higher viable sperm count and improved pregnancy rates, both fresh and frozen semen are viable breeding options. Frozen semen is an especially good option for those wanting to breed to a stallion from another area, if a client wants to store the semen for future use in years to come, or to prevent any shipping delays that can be encountered with fresh semen.

Embryo Transfer involves removing a 6-8 day embryo from the uterus of a bred “donor” mare and transferring that embryo into the uterus of an open “recipient” mare. This requires that both mares’ cycles are synchronized, with ovulations in both mares occurring on the same day, so that hormonal levels are consistent and to allow the donor mare the best chance to support the growing embryo. This is achieved through close monitoring and hormonal medication. Most recipient mares are also supplemented with progesterone treatments after receiving a transferred embryo. They are also examined at 11 days, 14 days, 21 days, and 28 days following ovulation to monitor the embryo’s growth and confirm pregnancy.

• Embryo transfer offers several advantages to regular pregnancy:
• Older mares who no longer have the uterine competency to maintain pregnancy can continue to produce offspring
• Mares currently in use can produce offspring without taking too much time out of their competition or show schedules
• Multiple foals can be produced out of a single mare during one reproduction season, by one or several stallions
• Embryos from valuable mares can be flushed and frozen for future use or shipped worldwide

Embryos are flushed from the donor mare’s uterus via lavage through a filter that traps and collects the embryo. The embryo is then examined by a veterinarian to ensure viability before being transferred directly into the recipient mare or shipped to another location. If a facility is to receive a shipped embryo to be transferred into a recipient mare, it is imperative that they are given as much notice as possible to properly align the cycle of the intended recipient mare.

It is important to note that the repeated process of embryo flushes and transfers over years can take a toll on their reproductive capacity. A point of diminishing returns can be reached in doing repeated flushes year after year, and the success rate may begin to decline. Allowing a mare to occasionally carry their own foal to term is believed to help allow the uterus and cervix to undergo positive changes to their reproductive health. However, embryo transfer is still a safe and effective way to maximize the genetic and reproductive capacity of your mare.

Recipient Mares

The “recip mare” is one of the most important factors in any good embryo transfer program. Ideal recipient mares are 3-14 years old, healthy, of good temperament, with a clean reproductive history. It is ideal for the recipient mare to be built similarly or larger to the donor mare to ensure safe delivery of the foal. Mares with soundness issues or unfortunate backgrounds can be offered a safe and comfortable life as a member of a recipient mare herd.

South Valley Equine Reproduction is well-equipped to work with subfertile or problem mares. We will work with our clients to create a management protocol that provides the best chances at producing a pregnancy for your mare. Although some mares may have fertility difficulties, most mares we work with have normal fertility. If your mare has had difficulty in the past maintaining or achieving pregnancy, or had a previous difficult birth that may have damaged her reproductive system, we may suggest a breeding soundness evaluation at the beginning of the reproduction process while your mare is in heat. This may include an external vulvar exam, palpation and ultrasonography, a vaginal speculum exam, uterine cultures for bacterial growth, and/or cytology labs of the reproductive tract. This exam can help identify subfertility issues and necessary treatments to resolve these complications.

Certain management protocols may be able to help achieve and sustain a pregnancy if issues are detected early. Veterinary staff can closely monitor the mare’s condition, follicular growth patterns, ovulation abnormalities, uterine edema, cysts, and fluid retention within the uterus. Detailed mare management practices provide the best chance for a sustained pregnancy in mares with previous breeding difficulties.

The South Valley Equine Reproduction Center provides stallion owners with a convenient and efficient program for fresh/cooled semen collection and shipments. Our staff will collect semen from your stallion and can ship it to desired locations throughout the United States, or it can be taken for personal or local client use. After each collection, the semen is processed, and a sample is evaluated to ensure maximum possible efficiency and motility. We record the results of each analysis including motility value, concentration levels, viability, and the semen extender used.

SVE prefers to communicate directly with the mare owners to arrange delivery, sign release forms, and collect payments. If shipping for next-day delivery, we utilize FedEx (or UPS if requested). For same-day shipments, semen is collected in the morning, delivered by a courier to Salt Lake City International Airport, and shipped via airlines to the destination city. Owners wishing to export semen to Canada must adhere to strict guidelines and permits. Please contact us for more information on specific import requirements if wishing to ship internationally.

To ensure minimal shipping and processing delays, the South Valley Equine Reproduction Center requires notice by 4pm the previous day for stallion collections and shipments. Owners can trailer their stallion to our facility, where our staff will then collect the semen and process everything for the shipment while the owner takes the stallion back home. We do provide “teaser” mares in the event that it is needed for your stallion.

The Reproduction Center offers a complete frozen semen program from collection and freezing to storage to distribution. Frozen semen is an excellent option for those looking to expand their breeding program or preserve their stallion’s reproductive capabilities. Not all stallions are good candidates for semen freezing; a breeding soundness evaluation and test freezing will need to take place to determine their compatibility. Once collected, the semen will then be prepared through several freezing protocols, including a thorough post-thaw analysis. If an acceptable protocol is achieved, we can then proceed to board the stallion at our facility and collect from him every other day until the desired number of doses is obtained.

Frozen semen must be properly stored to retain viability. The semen is cryogenically preserved in a tank filled with liquid nitrogen to maintain the temperature. SVE has several tanks that are monitored regularly to minimize the possibility of semen loss due to tank failure. Frozen semen can be stored at our facility (should space allow) for a monthly fee or shipped to any destination in the US. When shipping, we package the requested doses in a dry shipper container filled with liquid nitrogen to maintain temperature, and upon receipt and transfer of this container at its destination, it is then shipped back to us. Included with each shipment are detailed instructions for thawing and handling their specific batch of frozen semen.

A breeding dummy, or “phantom,” is an object that a stallion mounts so semen may be collected. This eliminates the need for a mare in heat to be mounted and reduces the risk of potential injury or disease transmission. Stallions can be trained to use the dummy in a short period of time, although many stallions may still need a mare in heat to be present as a “teaser” mare. If your stallion has never been collected for artificial insemination or evaluation, our team of experienced staff are able to help train your horse to the breeding dummy in order to prepare for future collections or evaluations.

It is recommended that stallions intended for breeding are examined prior to the start of each reproductive season to potentially diagnose any problems the horse may have. Potential fertility prediction and fertility issue diagnosis may allow us to treat any potential reproductive issues before they interfere with the stallion’s breeding performance. Proper management of certain infertility issues may help improve pregnancy rates.

Initial cooled semen evaluation can determine if the stallion’s semen is viable at 24 hours and 48 hours post-collection. This also helps determine the appropriate semen extender process that will best enhance the semen’s fertility. In a full breeding soundness examination, the external and internal genitalia are also assessed visibly and with ultrasound.

We have the capacity to stand 5 stallions during the reproduction season here at South Valley Equine. Our facilities were designed with efficiency and safety in mind. Each stallion has access to a 14×16’ stall with daily exercise on our hot walker, and we work with you to create a feeding schedule that will best suit your stallion. Semen collections can be performed either on a set schedule or as needed by the client.