New assisted reproductive technologies applied to the horse industry: successes and limitations

ABSTRACT

The development of assisted reproduction technologies (ART) in the horse has been slow compared with that in other large domestic animals. Besides artificial insemination and embryo transfer, other technologies based on in vivo and in vitro procedures of embryo production (IVP) have appeared, but the success rates of equine IVP are still far from allowing their use in routine protocols. Intracytoplasmic sperm injection (ICSI) is one of the most promising techniques applicable to the horse industry. With ICSI just one spermatozoon is injected into a mature oocyte, allowing the use of poor quality semen that could not otherwise be used for artificial insemination. Moreover, ICSI, followed by in vitro culture to the blastocyst stage, may be used in cases where multiple oocytes are available (e.g. when oocytes are obtained post-mortem). Those are just some examples to highlight the importance of ICSI in preserving genetic material. Cloning by Nuclear transfer (NT) can also be used for salvaging valuable equine genetics. The cloning process utilizing somatic cells is a powerful instrument for the preservation of animals with a unique genotype. Although recent reports on horse cloning show that it can be performed relatively efficiently, compared with other species, blastocyst production and thus live foal production is still low with this technique.(AU)