Efficiency of embryonic development after Intra-Follicular and Intra-Oviductal transfer of in vitro and in vivo matured horse oocytes

In vivo techniques, such as intra-oviductal Oocyte Transfer (OT) and Intra-Follicular Oocyte Transfer (IFOT) can be considered as alternatives to bypass the lack of efficient superovulation treatments and the inadequacy of conventional in vitro fertilization techniques in the horse. We compared embryo production following transfer of in vivo recovered oocytes (1) into a recipient’s oviduct or (2) into her preovulatory follicle either immediately after ovum pick up or (3) after in vitro maturation. Recipients were inseminated with fresh semen of a stallion with a known normal fertility. Ten days after surgery, rates of embryos collected in excess to the number of ovulations were calculated and compared for each group. Embryo collection rates were 32.5% (13/40), 5.5% (3/55) and 12.8% (6/47) for OT, post-IVM and immediate IFOT respectively. OT significantly yielded more embryos than immediate and post-IVM IFOT did. We also showed that in vitro matured oocytes could succesfully be used for IFOT. Our results also suggest that improvement of the IFOT technique could turn it into an inexpansive and easy to perform procedure that could be an answer to the inefficiency of superovulation treatments in the mare.