New Assisted Reproductive Techniques for Horses

Introduction Although embryo transfer provides a means of obtaining pregnancies from some mares that might not otherwise be capable of producing offspring, some mares cannot provide embryos for transfer. Mares in which embryo transfer may not be successful include those with: 1) failure of ovulation, 2) chronic endometritis (uterine inflammation), or 3) anatomical problems (e.g., cervical adhesions, etc.). However, these mares could be used as oocyte (egg) donors and continue to produce foals through other assisted reproductive techniques such as oocyte transfer, in vitro (test tube) fertilization or intracytoplasmic sperm injection. In addition, stallions with low sperm numbers and/or poor semen quality could also benefit from some of these newer technologies. Other reproductive technologies that are being developed include sexed semen, low-dose insemination procedures and cloning.