Embryo transfer is a fantastic way to get one or multiple foals out of your valuable mare. It allows Dr. Geary to take the genetic material from your mare and stallion of choice and place it in a recipient mare for gestation. Countryside Veterinary Clinic is proud to offer two package deals on this service.

What is it?

Equine Embryo Transfer (ET) is a reproductive technique that allows a mare to produce a foal without carrying the pregnancy herself. Instead, the embryo is collected from the donor mare and transferred into a recipient mare, who carries the foal to term. Embryo transfer allows valuable mares to avoid pregnancy related risks, continue competing or training, and to produce multiple foals in one season.

How does it work?

1. Breeding the Donor Mare

The donor mare and recipient mare will be left at our facility once the breeding process begins until the heartbeat positive check (HB+) to ensure that our doctors and staff have consistent and timely access to the mares during critical hormone cycles. Both are checked via ultrasound daily to track heat cycles and determine best times to breed the donor mare, and if the recipient mare’s cycle will line up.

The donor mare is then bred via artificial insemination with the chosen stallion. We have several stallions on-site to choose from, however you are welcome to use any stallion you would like! Both fresh cooled semen and frozen semen is acceptable. Our on-site stallions are listed here.

2. Embryo Collection (Flushing)

About 7–8 days after ovulation, the embryo is flushed from the donor mare’s uterus. This process involves flushing the mare’s uterus to collect any embryos that may have developed, and then searching for it under a microscope to determine if the process was successful or not. This process is typically done with a small amount of sedation for the comfort of the mare.

Once the embryo is removed the donor mare will begin to return to her heat cycle.

3. Recipient Mare

We do have options for you to use your own recipient mare, however, Dr. Geary owns a herd of recipient mares that typically make the process go by a little easier by being able to select a mare that already has a heat cycle lining up with the donor mare’s, rather than trying to synchronize them.

The embryo is then placed into the recipient mare’s uterus after it has been flushed. It is typically another 7-10 days before we are able to ultrasound the mare again to check if a pregnancy has been established.

It is about another 1-2 weeks after the pregnancy scan that we are able to ultrasound the mare again to determine if she is heartbeat positive, which will be at roughly 25-30 days gestation for the embryo.

Additional Information

We have two contract options if you choose to use one of Dr. Geary’s recipient mares. One involved being able to take the recip mare home with you once she is confirmed heartbeat positive, and the other is to leave her here through her pregnancy and foaling, and allowing you to take the foal once weaned between 4-6 months old.

There are many other details regarding this process not outlined in this overview. If you are interested in an embryo transfer with your mare, please reach out to us with any other questions! We can send you the contract to read and help clarify anything. Email is typically best for this, gearycvc@gmail.com