Repeated Superstimulation Facilitated Ovum Pick-Up and In Vitro Production (OPU-IVP) of Viable Bovine Embryos with No Apparent Adverse Effects on Donor Health

Objectives: of this study were to investigate effects of repeated superstimulation on the success of ovum-pick up and in vitro production of embryos (OPU-IVP) and donor health and evaluate the efficiency of a modified SOF sequential medium in producing viable embryos. Over 1 y, six cross-bred beef heifers and three beef cows were subjected to superstimulations and OPU-IVP. Oocytes recovered were used for in vitro embryo production and the resulting embryos were transferred as fresh or frozen-thawed. Number of follicles, oocytes recovered, cleavage and blastocyst rates substantially varied among individuals. However, repeated trials did not significantly affect the efficiency of OPU-IVP. The pregnancy rates (PR) 22 to 30 d after embryo transfer for in vitro-derived fresh embryos was similar to that of fresh in vivo embryos, whereas transfer of in vitro-derived frozen embryos reduced PR compared to frozen-thawed in vivo embryos. All recipient heifers diagnosed pregnant delivered a viable calf, suggesting developmental competence of the embryos. Repeated OPU-IVP had no apparent deleterious effects, as all donors had viable calves after ET. We concluded that multiple OPU-IVP cycles can be effectively performed for a prolonged interval to maximize embryo production from elite donors without compromising their reproductive health.