Embryo Transfer

Embryo transfer allows mares to be bred from without the mare having to carry a foal and take time off from competition. Instead an embryo is taken from the mare (donor) and transferred into a recipient mare who then carries the foal throughout pregnancy and gives birth to the foal. This also means that several embryos can be taken from one mare in a year, meaning you can breed multiple foals from your mare in a year. The procedure may also be suitable for mares that cannot carry a foal to term due to injury.

We offer non-surgical embryo transfer to either your own recipient mare or hired recipient mares.

For successful embryo transfer close management of both the donor and recipient mare is required.

Transfer Process

It is important that the donor mare and the recipient mares’ cycles are closely synchronised. For this to happen all mares need to be monitored closely via ultrasonography prior to any other procedures being undertaken.

In order to produce an embryo the donor mare must first be inseminated. This procedure can either be by artificial insemination with fresh, chilled or frozen semen or natural cover. The method used will most likely depend on the stallion chosen. Once it has been determined that the mares can be synchronised the donor mare is inseminated/covered at an appropriate time. Once the donor mare ovulates the recipient mare may be given an ovulation induction agent so she will ovulate approximately 48hrs after the donor. Although it is preferred that the recipient ovulates 24-48hrs after the donor it is still possible to perform the procedure if the recipient ovulates up to 4 days after the donor. Because the recipient has to ovulate within a small window of time compared to the donor, it is preferable to have 2 recipients per donor mare.

If fresh or chilled semen has been used the donor mare will undergo a flushing procedure to retrieve any embryos7 days after ovulation. If frozen semen has been used the flushing procedure is conducted 8 days after ovulation. If using your own recipient mare the embryo is transferred on site. A non-surgical transfer is conducted, which is similar to the insemination procedure used for artificial insemination. If using a hired recipient the embryo is specially packaged and sent by same day courier to the facility where the recipient mare is for transfer.

The recipient mare is then scanned for pregnancy at 14 days (which will be 6 or 7 days after transfer) and again at 25, 45 and 60 days.


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