Equine Embryo Transfer (EET) is a recognized reproductive technology that relates to the collection of an embryo (or embryos) from a donor female. It is a process that is becoming more and more popular in the equine world for obtaining foals. This technique involves recovering embryos from bred (donor) mares and placing them in a recipient mare who, in turn, carries the foal, or the embryo is transferred into a recipient or surrogate mother where a pregnancy can be established and maintained, resulting in the birth of live offspring. Embryo transfer has been used to a great commercial benefit in many species and has applications in equine procreation. There are several reasons for the use of this procedure. First, multiple foals can be produced from one mare (possibly genetically superior) in a breeding season. Second, it can be used to bring into being the foals from mares that cannot take time off from racing or showing. Third, embryo transfer can also be used to produce foals from sub-fertile mares that are incapable to successfully carry a foal to term. Fourth, young fillies that can produce feasible embryos but are not yet able to carry them may be used as donor mares. Fifth, older mares no longer competent of carrying a foal also make good candidates for embryo transfer. Last but not the least, the embryo transfer also cuts down on breeding injuries and the spread of venereal diseases to the horses. Nonetheless, this is not an accepted method of breeding for all breeds of horses. Better verify with the particular breed registry rather than choosing embryo transfer as a breeding method.

There are numerous opportunities for embryo transfer. (1) It permits horse breeders the entrance to a wider genetic group. (2) It allows owners of good quality mares to obtain progeny from their mares and to earn from the sale of embryos. (3) Mares can be bred throughout the year and the resulting embryos can be moved at a convenient time such as spring. (4) There is flexibility in importing and exporting of equine genetics. (5) It allows horse enthusiasts to buy the best quality horses at a fraction of the price of a live horse. Replication is applicable to equine veterinary custom as a system for economizing valuable equine genetics. Albeit the first studies on cloned equine pregnancies reported poor competence of production of cloned foals, 75%-100% of established pregnancies were lost, more current methods seem to be more efficient, with pregnancy rates per transferred embryo approaching those of standard embryo transfer and 50% or greater of established pregnancies going to term.

Although the horse was probably the first animal to experience and benefit from artificial insemination, it trailed the field somewhat with regard to the application of embryo transfer and other oocyte and embryo-related modern breeding technologies. But with a late run it is now back in mid-field and gaining fast on the other large domestic species in the application of the many technological advances of the past 20 years to sound breeding practice. Improvements in extenders and cryoprotectants have resulted in a veritable upsurge in the transport and insemination of cooled and frozen stallion semen, and parallel improvements in ovulation induction and synchrony, exogenous gonadotrophic stimulation of multiple fertile ovulations and simplified, more efficient methods for non-surgical transfer of embryos to recipient mares, coupled with relaxation of breed society registration restrictions, have together contributed to a similar upsurge in the application of embryo transfer to all breeds and athletic types of horses worldwide, with the continuing and notable exception of the thorough bred. While usual in vitro fertilization remains something of an un-jumped fence in equids, other contemporary breeding technologies like hysteroscopic low-dose insemination, fluorescence-activated sex sorting of stallion spermatozoa, between-species embryo transfer, embryo freezing and bisection, transvaginal ultrasound-guided oocyte collection, intracytoplasmic sperm injection for fertilization (ICSI), gamete intrafallopian transfer (GIFT) and nuclear transfer (cloning), have all been applied to equids with encouraging success. Cloning, especially, holds enormous promise for the sport horse industry to recreate champion geldings in stallion form for breeding purposes.