TECHNIQUE FOR EFFICIENT RECOVERY OF SHEEP OOCYTES BY LAPAROSCOPIC FOLLICULOCENTESIS

A simple and inexpensive pipette for in vivo recovery of sheep oocytes by folliculocentesis was developed. Two experiments were conducted to assess the recovery rate. In Experiment 1, 20 Merino X Corriedale ewe s were heat synchronized using intravaginal sponges containing 60 mg o f medroxyprogesterone acetate (MPA) for a period of 12 days. In Experi ment 2, 26 Merino X Corriedale ewes were synchronized with CIDR(R) dev ices for 12 days, with the original device being replaced by a new one on Day 10 (2 days before withdrawal). In both experiments, ewes were superovulated with a total dose of 16 mg of follicle stimulating hormo ne (FSH) given in six decreasing dosage injections, starting 48 h befo re sponge/CIDR removal. Folliculocentesis was performed 36-40 h after sponge removal, and 16-20 h after CIDR removal. Overall, an average of 12.5 follicles per ewe were punctured and 10.2 oocytes per ewe were r ecovered (recovery rate 81.9%). The differences between the two experi ments in terms of follicles punctured per ewe (10.8 vs. 13.7) and oocy tes recovered per ewe (8.5 vs. 11.5) were not statistically significan t (P > 0.05). The follicle size did not significantly (P > 0.05) affec t the recovery rate, although there was a tendency for higher rates of recovery from 15 mm follicles (88.5%) compared with follicles over 5 mm (79.5%).