A study on the ovarian follicular dynamic in Iraqi Northern Buffaloes

The aim of the present study was to test the hypothesis of wave pattern of follicular growth and to monitor the ovarian follicular dynamic in Iraqi buffalo cows. Reproductive tracts were collected at random intervals slaughtered at Mosul abattoir. According to morphological appearance of the corpus luteum, the estrous cycle was divided into four stages. The number of subordinate follicle (<5 mm in diameter) was higher during stage 1 (metestrous) and stage (proestrous and estrous) than during other stages of the estrous cycles, 13.5 +/- 6.08 and 4 9.41 +/- 3.94, respectively. There were fewer follicles (5-8 mm in diameter) during early diestrous and proestrous, 1.66 +/- 1.42 and estrous, 0.69 +/- 0.47 than during metestrous, 4.53 +/- 3.23 and late diestrous, 3.66 +/- 2.23. Follicles > 8-12 mm in diameter were more numerous during early diestrous, 1.62 +/- 1.29 and late diestrous, 1.03 +/- 0.72. A total 38 (64.6%; 82/127) animals examined showed follicles larger than 8 mm during early and late diestrous (stage 2 and stage 3). This indicated that these buffaloes developed two follicular waves in their cycle. Buffaloes did not show follicles larger than 8 mm during early and late diestrous were 45 animals (35.4%; 45/127), but all of these presented one large follicle during the following stage. These buffaloes develop only one follicular wave in their cycle. It could be concluded that, 64.6% of Iraqi buffalo cows develop two patterns of follicular waves, and 35.4% showed one wave of follicular dynamics.