Embryo transfer (ET), an advanced reproductive technology, has several potential uses in equine reproduction. ET can be used to increase the annual reproductive rates in mares. For example, some breed associations will allow multiple foals to be registered annually per donor mare. Young mares (2 years old) can have offspring through ET where otherwise this might not be a good idea. Females in use for shows, training or exhibition can have offspring without being removed from their primary use. Last, less fertile mares — particularly those with uterine problems — can have foals.
"TNH1003-Embryo Transfer in Mares," The University of Tennessee Agricultural Extension Service, TNH-1003 2/03 E12-4415-00-010-03, http://trace.tennessee.edu/utk_agexani/22