Characteristics of ovarian follicular dynamics throughout the estrous cycle of Egyptian buffaloes

Abstract

Data of 56 normal and 9 abnormal estrous cycles were collected from 9 Egyptian buffaloes ( Bublus bublis) to describe the follicular growth wave pattern. Heat was checked twice daily while, ovaries were scanned daily to monitor the patterns of follicular waves. Day of ovulation was determined when the largest follicle was replaced by corpus haemorrhgicum (CH). Number of waves/cycle, day of emergence of the follicular wave, characteristics of the dominant follicle and corpus luteum (CL) growth features were monitored. Buffaloes displayed mainly two types of follicular waves; two (46.4%) and three (53.6%). In cycles of three wave pattern, time of emergence of the 1st wave post-heat was longer ( P < 0.05) and number of recruited follicles/wave were larger ( P < 0.05) compared to the corresponding values of the two wave pattern. Number of recruited follicles in early follicular waves (1st or the 2nd) had larger number ( P < 0.05) compared to the subsequent ones. Follicles that reached ovulation in both types of estrous cycle had shorter life-span ( P < 0.05) than the previous ones. Life-span of CH, growing and regressed CL were 3.6 ± 0.6, 11.2 ± 0.8 and 4.4 ± 0.5 days, respectively with no difference in both types of follicular wave. Three types of ovarian disorders were observed. Follicular waves and CL growth features showed unique pattern for each individual. These results demonstrate that buffaloes display two main types of follicular waves with dominance of three wave type.