The Follicular Distribution during the Estrus Phase and the Enhanced Estrus Behavior of Crossed Ongole Heifers Stimulated with a Non-superovulation Dose of PMSG

The experiment's objective was to study the follicle distribution during the estrus phase and the estrus performance of the Ongole-crossed heifer by injecting a non-superovulation (NSO) dose of PMSG. Nine PO heifers were randomly assigned to one of three treatment groups, each receiving a different dose of PMSG injection, i.e., 0, 0.5, and 1.0 IU/kg BW, respectively; this was done at the early second follicular phase. The evaluation was conducted during the estrus phase to assess follicle distribution and estrus performance and to collect the reproductive tract for biometrics evaluation. The results demonstrated that PMSG injection at doses of 0.5 and 1.0 IU resulted in an increase in mean follicle diameter size above 0.8 cm by 7.08 % (P0.05) and 15.04 % (P0.05), respectively. However, the total number of follicles above 0.8 cm at 1.0 IU/kg BW dose remains high (5.33±2.52, P0.05), indicating a continued propensity for multiple calving. The results demonstrated that the estrus performance score was enhanced with the administration of increasing doses of PMSG, which was accompanied by an increase in the biometrics of the ovaries (P0.05) and the diameter of the uterine body, uterine horn, and cervix (P0.05). It was concluded that the NSO dose of PMSG could facilitate follicle development and enhance estrus quality without increasing the risk of multiple calving.