Embryo Transfer

Embryo transfer involves removing a very young embryo from the reproductive tract (uterus) of a donor mare and transferring it into the uterus of a recipient mare to complete gestation. Although the foal is born and nursed by the recipient mare, it is the genetic offspring of the donor mare.

Embryo transfer advantages

• Allows athletic mares in competition to continue their performance careers

• Medical risks associated with pregnancy and foaling are avoided for the donor mare

• Outstanding mares may have more than one offspring per year (can inseminate with different stallions for each estrous cycle)

• Obtain foals from mares with reproductive problems / aged mares / immature 2 year old mares

 

The Procedure:
1. The donor mare
The donor mare is treated in a similar manner to any other breeding mare. Her heat cycle is monitored daily and breeding is timed accordingly. 7 to 8 days after ovulation (depending if used fresh or frozen semen), the embryo is removed from the donor mare’s uterus by a flushing technique. The embryo is detected by microscope in the flush liquid and is then prepared for transfer.

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2. The recipient mare
The "recipient" mare or "surrogate" mare is the mare in which the embryo will be transferred for gestation, foaling and nursing. The recipient mare should be young (3 to 12 years old), reproductively healthy and approximately the same size as the donor mare (same size or a bit bigger). Currently, the Service Vét Ambul Équin Dre Fany Pairault does not have any recipient mares to rent; the client must therefore be able to provide his own recipient mares. The recipient mare’s cycle is monitored daily by ultrasound examination and is manipulated so that the recipient mare ovulates in a 48h window following the donor mare. Ideally, 2 to 3 recipient mares are prepared for one donor mare per estrous cycle. Consequently, the best recipient mare could be selected to match the donor mare.