Evaluation of the follicular population and oocyte quality of zebu cows (Bos indicus) with anovulatory anestrus

Abstract

The study aimed to evaluate the ovarian follicular population and oocyte quality of local zebus with anovulatory anestrus. It was conducted at Ngaoundere municipal slaughterhouse, Adamawa region in Cameroon. Of the 496 genital tracts examined, 145 (29.2%) presented an anovulatory anestrus. The mean number of follicles per cow was 37.5 ± 25.2. The number of small, medium and large follicles per cow were 21.7 ± 18.7, 14.9 ± 12.1 and 0.9 ± 1.1, respectively. The mean follicular populations of cyclic or in anovulatory-anestrus cows were 29.1 ± 18.1 and 41.9 ± 27.3 (p < 0.05), respectively. The number of oocytes per cow were 15.5 ± 4.5 and 15.6 ± 3.8 (p > 0.05) in cyclic and anestrus cows, respectively. The number of grade I, II, III and IV oocytes were 4.5 ± 4.1 (28.5%), 4.1 ± 3.7 (26.2%), 2.3 ± 2.4 (14.8%) and 4.8 ± 5.6 (30.5%), respectively. This study showed that anovulatory anestrus tended to enhance the follicular population but had no effect on the oocyte yield. The number of grade I and II oocytes acceptable for in vitro maturation were significantly lower in cows with anovulatory anestrus than in cyclic cows (p < 0.05).