Effect of the presence of a dominant bull on performance of two age group bulls in libido tests

Abstract

It is not clear if the presence of a dominant bull affects in different ways the sexual behavior of two age groups of young bulls, and if its effect is different when this mature bull is maintained in an adjacent pen, rather than when he has physical contact. Twelve 15 month old and ten 27 month old sexually naive Simmental bulls were libido tested under the presence or absence of a dominant bull under two trials: (1) individual sexual performance tests were conducted. On alternate tests days, a mature bull was present in an adjacent pen where the stimulus female stanchion was attached. In trial (2), same age animals, as a group, were exposed to a female, and on alternate test days, a mature bull was present, allowing physical contact with the tested bulls. In trial (1), no difference was found in sexual behavior activities or libido scores within age groups between treatments ( P>0.05). Nevertheless, in the older age group, the time spent close to the stimulus female was reduced during mature male presence ( P=0.02). In trial (2), both age groups of bulls were affected by the physical presence of the mature bull, reducing the number of times that the animals were seen in sexual proximity with the stimulus female ( P<0.01). It was concluded that the sexual behavior of both age groups was affected in different ways when a dominant bull was present.