Technique for efficient recovery of sheep oocytes by laparoscopic folliculocentesis

Abstract

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 × Corriedale ewes were heat synchronized using intravaginal sponges containing 60 mg of medroxyprogesterone acetate (MPA) for a period of 12 days. In Experiment 2, 26 Merino × Corriedale ewes were synchronized with CIDR® devices 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 hormone (FSH) given in six decreasing dosage injections, starting 48 h before 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 recovered (recovery rate 81.9%). The differences between the two experiments in terms of follicles punctured per ewe (10.8 vs. 13.7) and oocytes recovered per ewe (8.5 vs. 11.5) were not statistically significant ( P>0.05). The follicle size did not significantly ( P>0.05) affect the recovery rate, although there was a tendency for higher rates of recovery from 1–5 mm follicles (88.5%) compared with follicles over 5 mm (79.5%).