SEXUAL BEHAVIOR OF CORRIEDALE AND MERINO X IDEAL CROSSBREED RAMS WITH ESTRUS-SYNCHRONIZED CORRIEDALE EWES

The reproductive performance of the sheep herd is one of the essential factors to succeed on productivity. Among tools that assist animal reproduction, is the knowledge of the sexual behavior of males. High sexual performance rams will probably serve a greater number of ewes in a shorter period of time, increasing the pressure of selection and dissemination of the desired genetic material. In the present study, sexual behavior of two young rams was evaluated in the presence of estrus females, and comparing: the level of plasmatic testosterone, service ability, libido and sexual behaviors observed and quantified individually for each male. Two rams were used: one Corriedale; and other, Merino x Ideal cross, aged between one and two years; and forty-four Corriedale adult ewes which had their estrus induced with intramuscular application of prostaglandin. During the mating and evaluation period of sexual behavior, males remained throughout the day apart from the ewes, and in the late afternoon they were introduced in their presence. Sexual behaviors were not influenced by age or previous sexual experience. The ram with the highest libido and service capacity had relatively higher levels of plasmatic testosterone and lower Reaction Time. It was concluded that young rams without previous experience can have higher service capacity, higher libido and fertility levels and consequently higher levels of testosterone.