Biotechnology in equine reproduction: Prospects and limitations

Assisted reproduction techniques for horses are developing relatively slowly, compared to those for other domestic animals, because of a wide range of species-specific barriers, such as the lack of efficient methods for superovulation, frequent disorders of in vitro oocyte maturation, and the absence of standards for in vitro embryo culture. Despite these obstacles, attempts are being made to improve various biotechnological methods. In recent years, offspring have been obtained by cloning. A method alternative to the in vitro fertilization of oocytes is transfer to recipient mares (GIFT). Methods for oocyte and embryo cryopreservation are being improved. In recent years, there has been a great interest in studies of embryo biopsy for the genetic diagnosis of embryos. Despite promising results of several studies, it is necessary to intensify work on the optimization of methods for in vitro embryo production (in vitro fertilization, cloning), cryopreservation of gametes and embryos, genetic embryo diagnosis, and artificial insemination of mares with sex-sorted sperm.