Comportamento sexual de carneiros corriedale e cruza merino x ideal em ovelhas sincronizadas

Abstract

Reproductive performance of ovine cattle is essential to productivity. To achieve it, use of tools to aid reproduction is necessary. Among them, is understanding male reproductive behavior, because higher reproductive ability males will mate to a greater number of ewes in a shorter period, thus rising selection pressures and the dissemination of desirable genetic material. The aim of the present work was to evaluate mating behavior of two young rams, in the presence of estrous females, and to compare plasmatic levels of testosterone, breeding ability and sexual behavior traits measured and observed individually for each male. Two rams were used: one Corriedale and another of a Merino x Ideal cross, with ages between one and two years old. The females were forty-four Corriedale adult ewes in prostaglandin- induced estrus. During mating and evaluation period, males remained during the day for from the females, and in the late afternoon they were released within the synchronized females. Sexual behavioral traits were not influenced by age on previous mating experience. The ram which showed higher libido and service ability had relatively higher levels of testosterone and shorter reaction time (RT). It can be concluded that rams that are young and have no previous mating experience can have higher service ability, libido and higher fertility, as well as higher testosterone levels.