The effectiveness of different hormone protocols for improving ovarian function before ovum pick-up in crossbred Japanese black cattle.

Background and Aim: Producing and transferring embryos Materials and Methods: 30 crossbred Japanese black cows were divided into five equal groups, which were either untreated or treated with different hormone protocols before OPU. Group 1 (cows in estrus) and group 2 (cows in diestrus) were the untreated controls. Cows in group 3 were treated with GnRH + FSH + CIDR + PGF Results: Group 3 presented the highest large follicle numbers, and groups 3-5 had more medium follicle numbers, not different among groups but they had this parameter more than those of control groups 1 and 2. Moreover, groups 3-5 did not differ in combined grades A + B oocytes (good-quality oocytes). Groups 3 and 4 had more A + B oocytes than control groups 1 and 2, whereas group 5 was not different in this parameter from group 1. Conclusion: Among the three hormone protocols, EB treatment proved the most cost-effective and efficient, yielding more high-quality oocytes compared to the non-treatment protocols. To reduce the limitations of EB use in the future, this study suggests researching natural EB phytoestrogens as alternative treatments for improving ovarian function before OPU in other cattle breeds.