Multiple ovulation and embryo transfer with fresh, frozen and vitrified red deer (Cervus elaphus) embryos in Argentina

Two multiple ovulation and embryo transfer (MOET) programs with fresh, frozen and vitrified red deer embryos were carried out during the reproductive season of 2005 and 2006 in a local breeding farm in Argentina. Multiparous (n = 10 and 9, respectively) weaned hinds were used as donors for each year. The estrous synchronization treatment of donors and recipients consisted of inserting an ovine intravaginal sponge containing medroxiprogesterone acetate (MAP) for 12 days. Superovulation was conducted with a total dose of 180 mg of NIH-FSH-P1 (Folltropin®-V, Bioniche, Belleville, Ontario, Canada), given i.m. in eight decreasing doses every 12 h (40, 40; 27, 27; 15, 15; 8, 8 mg), from days 10 to 13. Donor females were mated with one stag of proven fertility. The recovery rate was 84.1% (122/145), obtaining 45.1% (55/122) of transferable embryos, 24.6% (30/122) of degenerated embryos and 30.3% (37/122) of unfertilized oocytes. Pregnancy rates after transfer of fresh, OPS vitrified/warmed and ethylene glycol (EG) frozen/thawed embryos were 64.3% (18/28), 53.3% (8/15) and 70.0% (7/10), respectively. Vitrification and freezing with ethylene glycol procedures constitute an interesting alternative for red deer embryo cryopreservation.