Bovine embryo production with a combination of SOV and OPU-IVF

Summary The aim of the present study was to examine the efficiency of total embryo production with a combination of SOV and OPU-IVF performed at 48 h after onset of estrus during the SOV. Forty-two Japanese Black cows were divided into two groups, the control group and the OPU-IVF group. In the control group, 25 cows were superstimulated with twice-daily injection of FSH with decreasing dosage manner for 4 days (total FSH is 24 AU). After 48 h of the first FSH injection, 500 micro g cloprostenol was injected i.m. Cows showed estrous behavior were inseminated artificially with 0.25 ml frozen semen and injected 100 micro g GnRH. After 7 days, embryos were collected nonsurgically from uteri by flushing. In the OPU-IVF group, 17 cows were treated with the same procedures as the case of cows allocated to the control groups. Then, OPU were performed to collect oocytes at 48 h after the onset of the estrus. The oocytes collected were cultured in TCM199 supplemented with 5% fetal calf serum (FCS) for 20 h, and the oocytes were inseminated into BO solution supplemented with caffeine, heparin and spermatozoa (10 * l0E6/ml). Then, IVM-IVF oocytes derived from OPU were co-cultured with cumulus cells for 9 days in TCM199 supplemented with 5% FCS. Blastocysts derived from OPU-IVF were transferred to recipient cows to confirm their competence of pregnancy. No significant difference was observed in the number of CL, persistent follicles, embryos collected and viable embryos between the control and the OPU-IVF groups. The oocytes collected showed low quality. The number of oocytes developed to blastocysts was 0.9=+-1.1 per one trial. In total embryo production, the OPU-IVF group recorded 6.3 blastocysts while the control groups recorded 4.6 blastocysts. These results indicate that OPU during SOV does not adversely affect embryo production by SOV but increases the total number of blastocysts compared with the number of blastocysts derived from only SOV treatment.