Recipient mares must be palpated daily to record ovulations. It is essential for the donor mare to be synchronized with the recipient that will receive her embryo. The recipient can ovulate the day before, the same day, or up to two days after the donor to be acceptable. We have about 100 recipient mares cycling all the time, we calendar the ovulations, and have mares available for up to 5 embryo transfers per day. Recipients for oocyte transfer must be in estrus with a preovulatory follicle which we flush to keep the recipient egg from becoming pregnant. Recipients for ICSI will have ovulated a day after the oocyte was flushed from the donor mare.