Short-term individual housing temporarily reduces the libido of bulls

The objective of the present study was to determine the effects of short-term (6 wk) individual housing on the sexual interest (libido) of sexually experienced bulls. Twenty-two Hereford bulls reared with both males and females (BMF) or in all-male groups (BM) and approximately 21 mo of age were given free access for 40 min to five restrained females in hormonally-induced estrus and restricted access for 30 min to a single enclosed estrous female on two separate occasions. Free-access tests were administered to bulls in groups of five or six individuals, whereas bulls were tested individually in restricted-access tests. After testing, half the animals were housed individually (physically isolated from conspecifics) and half remained in group housing for a 6-wk period. Libido tests were administered again at the end of the treatment period and 2 wk after reinstatement of group housing for the experimental subjects. Individually housed bulls exhibited fewer mounts (P less than .001) and spent less time with females (P less than .01) in tests administered during physical isolation than before or after treatment. Individual housing did not affect BMF and BM bulls differentially. In conclusion, short-term individual housing temporarily reduced libido of beef bulls.