OVARIAN FOLLICULAR DYNAMICS DURING IMMEDIATE POSTINSEMINATION PERIOD AND SUBSEQUENT CONCEPTION IN GIR AND CROSSBRED CATTLE

Abstract

Transrectal ultrasonography aided ovarian follicular dynamics of 20 cattle (9 Gir, 11 Crossbred) during 21-day post-insemination period was investigated to know the differences in cattle that subsequently conceived or failed to conceive. During this period, two follicular waves were observed in majority (p>0.05) of conceived (Gir, 66.7%; Crossbred, 80.0%) as compared to their non-conceived (Gir, 50.0%; Crossbred, 66.7%) counterparts. The linear growth and regression rate of 1st dominant follicle as well as the maximum diameter of 2nd dominant follicle were lower (p<0.05) in conceived cattle of both breeds compared to non-conceived cattle. Further, in the conceived crossbred counterparts, the 1st dominant follicle had delayed (p<0.05) beginning of regression phase (15.7±0.2 vs. 14.0±0.4 d) of shorter duration (4.7±0.6 vs. 7.0±0.4 d) as compared to non-conceived counterparts. In brief, a differential ovarian follicular dynamics exists during immediate post-AI period in dairy cattle.