In Vitro Development of Bovine Oocytes Collected from Ovaries of Individual Cows after in Vitro Fertilization

Abstract

Bovine follicular oocytes (oocytes-cumulus complexes) were matured, fertilized and developed in vitro utilizing a co-culture system with bovine cumulus cells. Oocytes from individual cows were cultured separately throughout the experiment.
Experimental groups were classified into three groups based on the number of oocytes collected from individual cows: Group 1, n ?? 20; Group 2, 21 ?? n ?? 30; Group 3, n ?? 31.
Although there were no significant differences in the development rates of oocytes among 3 groups, percentage of embryos developed to blastocyst stage in Group 3 tended to be higher than those of Groups 1 and 2 (14.3% vs 9.0% and 7.9%). There were considerable differences in the rates of development to blastocyst stage within the same group (Group 1, 043.8%; Group 2, 026.1%; Group 3, 025.0%). The number of blastocysts obtained from individual cows after in vitro culture varied from 0 to 11. (mean=3). The result of this study indicates that oocytes from individual cows have different ability of development in vitro.