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Equine embryo under magnification
Equine Embryo Transfer

The Equine Reproduction Laboratory at Colorado State University offers a commercial equine embryo transfer service. There are two primary ways to participate in the program:

  1. You may bring your mare to CSU for us to manage the entire process from breeding to transfer, or
  2. You may breed and flush your mare at another facility and ship the embryo to CSU for transfer.

Pregnancy rates for recipient mares in each category are comparable; approximately 75-80% at 14 days and 65-70% at 50 days. In addition to these options, special arrangements can be made if the donor mare will be bred elsewhere and brought to CSU for embryo collection and transfer, or if you wish to provide you own recipient mare(s). Before participating in the embryo transfer program, it is important for each owner to know the regulations of their breed registry.

Communication is the key to a successful program. If you plan to ship an embryo, please call and let us know when your mare is in heat and, most importantly, the day she ovulates. This allows us to ensure that a suitable recipient is available for your mare. It is important when shipping embryos to find professionals with appropriate equipment to breed, flush and handle embryos.

Embryos are generally collected from the donor mare on day 7 after ovulation. The first pregnancy check on the recipient mare is day 11 of gestation (4 days after the transfer) and a definitive positive or negative is known by day 16 of gestation (9 days after transfer).

If you are interested in entering your mare in the program or have any further questions, please contact Dr. Pat McCue at the Colorado State University Equine Reproduction Laboratory at (970) 491-8626 (tel) or (970) 491-7005 (fax), or e-mail

Learn more about equine embryo transfer.

Information and Contract​​