THE IN-VITRO DEVELOPMENTAL COMPETENCE OF BOVINE OOCYTES CAN BE RELATED TO THE MORPHOLOGY OF THE OVARY

This study was designed to assess whether the developmental potential of bovine cumulus-oocyte complexes (COCs) could be related to the morp hology of their originating ovary, providing a simple, noninvasive and objective selection criterion. Ovaries were divided into 3 categories on the basis of: A) presence of a follicle > 10 mm in diameter, B) pr esence of more than 10 follicles of 2 to 5 mm in diameter and no folli cles > 10 mm, and C) presence of less than 10 follicles of 2 to 5 mm i n diameter and no follicles > 10 mm. The COCs, isolated from ovaries o f Category C, showed lower rates of maturation and blastocyst formatio n than those from Categories A and B. Moreover, blastocysts derived fr om Category C ovaries had fewer cells than those derived from the othe r 2 categories. It is concluded that ovarian morphology is a simple an d noninvasive parameter for an effective selection of oocytes with bet ter developmental competence. (C) 1997 by Elsevier Science Inc.