Equine Embryo Transfer - Frequently Asked Questions

What is embryo transfer?
Equine embryo transfer is a procedure performed by a veterinarian that transfers a fertilized egg (embryo) from a donor mare to a recipient mare. The recipient, or surrogate mare will then carry the pregnancy to term and deliver the foal 11 months later. When the foal is born, it retains the DNA of the original donor mare and stallion to which she was bred.

What are the reasons for doing embryo transfer?
There are many different reasons for choosing embryo transfer for your mare. Here are the most common reasons:
∙Allows a donor mare to continue in training or competition
∙Allows several offspring per year from the same outstanding mare (follow individual breed
 guidelines where applicable)
∙Eliminates the wear and tear of gestation and lactation on the valuable donor mare
∙Allows offspring from reproductively challenged mares

How does embryo transfer work?
The donor mare is bred and has her cycle monitored so that the precise day of ovulation is noted. It is also important to know whether there was a single or double ovulation, since a double ovulation may result in two embryos being produced in a single cycle. The fertilized egg is allowed to develop for 7 days, before it is flushed from the uterus. The resulting embryo is then transferred into a special embryo holding medium prior to being transferred to the waiting recipient mare. The recipient or surrogate mare has also had her cycle precisely monitored so that her ovulation date matches up with the donor mare. The embryo is inserted into the recipient mare’s uterus, where it will hopefully become a successful pregnancy.

How soon after the embryo transfer will I know if my recipient mare is pregnant?
When the embryo transfer is performed the embryo is usually about 7 days old. A normal pregnancy check can be performed about 8 days after the embryo transfer is performed, when the embryo is 15-16 days old.

What if my mare has multiple follicles that ovulate?
If your mare ovulates 2 or even 3 follicles, there is a chance that you will get 2 or 3 embryos from the flush. You can choose to have all of the viable embryos transferred into recipient mares (one per mare). This increases your chances of having at least one foal in case one of the embryos doesn’t make it. This also means that you may produce more than one foal, so you need to be prepared for that as well.

What kind of mare makes a good embryo donor?
The short answer is that any mare can be used as a donor for embryos. Most donors are typically mares that are actively showing or competing, or mares that have breeding soundness issues (cervical tears, can’t maintain pregnancy, etc.). Some mares that tend to have multiple ovulations also make good candidates because you eliminate the chance of her carrying twins.

What kind of mare makes a good embryo recipient?
Good recipient mares are young, big-bodied mares with a healthy, disease-free reproductive tract.

Do I have to bring my mare to you to perform all breeding services?
No. If you live out of state or have a veterinarian who is capable of doing your breeding work, then we can work with your veterinarian to accomplish your goals. Some people chose to have their veterinarian do all of the breeding and embryo transfer work, and we just supply the recipient mare. Others chose to have their veterinarian breed their mare, but then have us do the embryo transfer work. Please view our embryo transfer services link to view the different options that we provide.

Can I use one of my own mares as a recipient mare?
One of the keys to a successful embryo transfer is the timing of both the donor mare’s ovulation and the recipient mare’s ovulation. We keep a large herd of mares so that we continually have mares ovulating. It can be difficult and very frustrating to try to synchronize your mare’s ovulation with a single donor mare’s ovulation. The recipient mare must also be of complete breeding soundness. Our mares are mostly young, maiden mares which is usually the best type of mare for the job.

If I don’t want to keep my recipient mare, can I bring her back for a refund?
Yes. We will perform a breeding soundness exam and if we can use her in the embryo program again, you will receive either a $500 refund or credit for future embryo transfer services.

What is the cost of doing an embryo transfer?
The costs can vary. The main expense is purchasing the pregnant recipient mare for $3000. You will also have embryo transfer fees, which are $250 per cycle. You also have to consider your breeding expense, including the veterinarian fees for checking her cycle, AI, and possibly stallion collection and other related stallion fees. In general, you can expect to spend $4000-5000 for doing a single embryo transfer. Costs can increase if your mare is bred several times before a viable embryo is produced.