Embryo Transfer is the process of transferring a fertilized egg (Embryo) from and donor mare to a surrogate mare.
The most common indications for ET include mares incapable of carrying a pregnancy due to age or injury and young performance mares.
Because mares have a long and variable heat cycle synchronizing the donor with one recipient is not recommended. We recommend that three recipient mares are synchronized with the donor mare. Alternatively, we have worked with several different recipient farms that maintain herds of mares large enough to insure that one is always available and “in sych” with a donor. We notify the farm when the donor mare comes into heat and when she ovulates.
The embryo is collected from the donor mare by flushing the uterus seven days after ovulation. Special fluids are infused into the uterus then drained out through a filter that captures and holds the embryo in the collection cup. The recovered fluid is searched under a microscope to find the embryo. Once identified the embryo is rinsed through four sterile fluid baths before it is ready for transfer. The next step depends on where the recipient mare is located. If the donor is on site the transfer is performed immediately. The embryo is drawn up inot a special straw similar to one used to inseminate a mare. The straw is passed through the cervix of the recipient mare and the embryo deposited in the uterus. The embryo can also be placed in a semen shipping container and shipped to a recipient mare farm. A third alternative is to vitrify (similar to freezing) the embryo and store it until a recipient mare is available.