THE ASSESSMENT OF SEXUAL PERFORMANCE IN YOUNG BOS-TAURUS AND BOS-INDICUS BEEF BULLS

Yearling beef bulls, representing different Bos indicus and Bos taurus breeds, were given two sexual performance assessments (libido score, number of services, time to first mount and time of sexual inactivity) at four test periods (January, April, July and October) in 1991 (Tria l 1) and 1992 (Trial 2) at the Subtropical Agricultural Research Stati on, Brooksville, Florida. Breed and test period, as well as their inte ractions, influenced most results, Sexual performance assessments gene rally improved with age in Bos taurus breeds, but not in Bos indicus. The temperate Bos taurus breeds (Angus and Hereford) were most sexuall y active, the tropically adapted Bos taurus breeds (Senepol and Romosi nuano) intermediate and the two Bos indicus breeds (Brahman and Nellor e x Brahman) were least active, Service rates were generally low. Seas onal patterns in sexual performance were not apparent, with breed and year differences occurring. Although breeds showed consistent test res ults, the failure of Bos indicus bulls to service in any test, indicat es either sexual immaturity, or inadequate procedures for assessment o f sexual performance in this breed group.