INVESTIGATIONS ON THE INFLUENCE OF INDIVIDUAL CHARACTERISTICS OF THE DONOR COW ON THE DEVELOPMENT OF INVITRO FERTILIZED OOCYTES IN CATTLE

Bovine oocytes have been matured, fertilized and cultured in vitro sep arated by donor cows. The breed of the donor cow, the reason for slaug htering the animal, the stage of cycle, the number of tertiary follicl es as well as the number of oocytes per culture well were registered. The influence on the number of oocytes per cow, the cleavage rate and rate of transferable stages was investigated. More transferable stages occurred in Holstein Frisian cows than in Simmenthal cows (32% and 28 %, respectively). In pregnant cows, more oocytes could be punctured th an in cyclic cows (23.2 oocytes/animal and 13.6 to 15.5 oocytes/animal , respectively) and higher number of oocytes developed to the morulae or blastocyst stage (36% in pregnant cows, 22 to 28% in cyclic cows). In cows with chronic diseases, cleavage rate as well as number of tran sferable embryos decreased (cleavage rate between 43 and 53%, 16 to 24 % morulae and blastocysts). The number of transferable embryos increas ed by the number of oocytes per animal that means per culture well (fr om 25 to 33%).