Induction of the best moment to the Ovsynch protocol beginning through the presynchronization by prostaglandin in buffalo cows (“Bubalus bubalis”)

Abstract

The objective of this experiment was to evaluate the efficiency of the Ovsynch protocol in water buffalo cows, by the utilization of nafarelin like GnRH analogous and by the induction of the best moment to the protocol beginning through the presynchronization of the estrous cycle with prostaglandin. Reproductive season, body condition score (BCS), body weight, uterine tonus, size of the ovaries, serum progesterone level at the beginning of the protocol and the review with the bulls after the inseminations were also evaluated. Eighty three Murrah buffalo cows were randomly divided in two groups. One group were evaluated in the favorable reproduction season (n=42) and the other for the unfavorable reproduction season (n=41). For each season, the groups were subdivided in two, which one was treated with the Ovsynch protocol and the other group for Presynch protocol. There was no statistical difference for artificial insemination pregnancy rates (AIPR) among the protocols and reproductive season. However, there was a difference in the accumulated pregnancy rates (APR) after the reviews with the bull. The BCS did not show influence in the AIPR, while the APR of the buffalos with BCS > 2.5 (66.13%) was superior (P=0.003) than the APR animals with BCS < 2.5 (28.57). A positive correlation was observed between the body weight and AIPR (+0.35; p=0.001) and the body weight and APR (+0.47; 0.0001). Ovaries size showed influence on AIPR and APR for both treatments.