ABSTRACT
Introduction The birth of the first calf from a frozen-thawed embryo was in 1973, but it was not until 1982 that scientists in Japan reported the birth of the first foal from a frozen-thawed equine embryo. The following year Colorado State University produced 2 foals from 4 frozen-thawed embryos transferred to recipient mares. Since that time there have been numerous studies evaluating various methods for long-term storage of equine embryos. However, only recently cryopreservation of equine embryos has gained popularity and become a viable clinical procedure.
