Ovum pick-up in sheep: efficiency of in vitro embryo production, vitrification and birth of offspring

摘要

At the Institute of Zootechnics Research Farm, Bonassai, Italy, during the breeding season of 1997-98, 20 Sarda [Sardinian] dairy ewes aged 4-8 years were each inserted with intravaginal progestagen-impregnated sponges (FGA) containing 40 mg fluorogestone acetate for 13 days. 96 IU FSH (Ovagen) was given at 12-h intervals on days 10, 11 and 12 after FGA. 415 oocytes were aspirated from 522 follicles (11.5 oocytes/ewe), and 328 of them (9.1 oocytes/ewe) were selected for in vitro embryo production procedure. Development into blastocysts occurred in 98 embryos (2.7 blastocysts/ewe), of which 64 were vitrified and 34 were transferred, in pairs, directly to recipients. The pregnancy rate at 80 days for fresh and vitrified embryos, did not differ significantly (47.1 vs. 42.8% respectively), but there were significant differences in lambing rates between the 2 groups (41.2 vs. 23.8%). Overall, 24 lambs were born; all had normal birth weights, but head deformities were observed in 2 cases. It is concluded that it is possible to obtain repeated embryo production and viable offspring using these techniques in sheep.