What is Embryo Transfer? It is the removal of a six to eight day old embryo from one mare (donor mare) and the transfer of it into another (recipient) mare's uterus to continue development.

Why Embryo Transfer? It is a very important technology in equine reproduction because it allows breeding of mares that may no longer be able to carry foals to term, i.e. mares with previous foaling injury, infection of the uterus or just old age. Furthermore mares with a heavy performance schedule are great candidates and some people use the technology to produce multiple foals from a single mare in one year.

What is Involved? The donor mare is cycled and bred in the usual manner, however, her cycle must be carefully followed. Daily palpations/ultrasounds are required. Precise detection of ovulation is critical. Exactly 7 days post ovulation, the embryo is "flushed" from the donor mare, specially packaged, and shipped to the transfer center. The transfer center chooses a recipient and places the embryo into this specially chosen recipient mare.

Why Use a Transfer Center? In order for the recipient mare to be able to accept the embryo as her own, her heat cycle must be timed to that of the donor's cycle. Two or three potential recipient mares are begun on an estrus synchronization program. The recipient mares need to be within 24-48 hours of the donor mare's ovulation schedule. This must occur for the recipient mare's uterus to be ready to accept an embryo.

What is the Procedure? Seven days following ovulation, the donor mare's uterus will be flushed with a special saline-type solution to collect the embryo(s). A special catheter and filter cup is used to help collect the embryo(s) as the fluid is recovered from the uterus. The filtered solution is examined under a microscope. Once an embryo is located, its quality is scored. The grades are from 1-5; one being excellent and 5 being a non-viable embryo. The grades are based on the morphologic appearance and apparent health of the embryo. Once recovered it can be transferred into a recipient mare immediately, or within 24 hours if it is being shipped to another facility. Once a surgical procedure, today, the transfer is carried out by placing the embryo in a "transfer gun". It is gently advanced through the vagina and the cervix into the uterus where the embryo is deposited.

What about the Recipient Mare? The recipients are housed and monitored for pregnancy, then they are usually leased or purchased for the year. After a recipient has been confirmed in foal, she is housed at the facility for 90-150 days depending on the program in which you participate. Then, she can be released to your farm. Most contracts provide for a refund if the recipient is returned in good condition.

Is Every Mare an Acceptable Donor Mare? Not all mares are fit to donate an embryo. Depending on the reproductive history of the mare, and in order to achieve the highest success rate for the collection of embryos, diagnostic tests such as Ultrasonic Evaluation of Ovaries and Uterus, Vaginal Examination, Uterine Culture/Sensitivity, Cytology and Biopsy may be recommended.

What Rate of Success Should I Expect? In young, healthy donor mares, the embryo recovery rate per cycle is about 60%, and the successful establishment of a pregnancy in a recipient mare is also about 60% when a grade 1-2 embryo is transferred, according to Chris Schweizer, DVM, Dipl. ACT (The Horse Magazine-April 2003). "Success rate for both embryo recovery and successful pregnancy decrease as the donor mare's innate fertility decreases and the embryo quality declines," she says.

Financially ~ What Can I Expect in Costs? You should budget about $5000 to $7000 for an embryo transfer. Please note that most costs are present whether or not an embryo is retrieved. Not every embryo flush attempt will be successful. For the donor mare management per cycle you must factor in ultrasound examinations, farm calls, board, reproductive medications as required and any transport costs. You will need to choose a commercial transfer center that will receive the embryo and perform the transfer. They will ask you to sign a contract for the recipient mare and may require a down payment. Prices range from $2500 to $4500. Read the contracts carefully before proceeding. We will help you with any questions you may have.