Comportamento sexual de touros Nelore ( Bos Taurus Indicus) e sua caracterização temporal em monta natural a campo

Abstract

The objective of this study was to evaluate the sexual behavior of zebu bulls (Bos taurus indicus) at pasture through time, considering the pre and post-copulation periods. Eleven Nelore bulls were individually confined together with 12 females in induced estrous. The interaction between each bull and the females was evaluated, in average, for 72 successive hours. Three periods were then established: pre-first copulation, peri-first copulation and post-first copulation periods. The sexual events evaluated were: Sniffing/Licking Cows Body, Sniffing/Licking Cows Genitalia, Flehmen Reflex, Mount Reflex, Penis Exposure, Mount Attempt, Mount without Penis Exposure, Aborted Mount, Complete Mount, Chin Resting and Follow the Female. In general, the manifestation of the events did not tend to vary linearly with the observation hours. Nevertheless, significant differences (p < 0,05) in the distribution of the events along the three observation periods were observed for: Mount Reflex, Penis Exposure, Mount Attempt, Aborted Mount, Complete Mount, Chin Resting and Follow the Female. These events were proportionally more manifested during the peri-first copulation period. After the first copulations an increase in the similarity between the sexual behaviors of the bulls was observed, possibly indicating the best period for the sexual evaluation of the animals. The events Mount Reflex, Sniffing/Licking Cows Genitalia and Flehmen Reflex were the most important ones in terms of the sexual behaviour of the bulls. It was not possible, though, to identify a homogeneous temporal pattern of sexual events manifestation by Bos taurus indicus during court and mount period.