ABSTRACT
Genetic progress of the commercial beef cattle population depends heavily on the amount of genetic progress possible in the bull-producing herds of the breed. To determine the value of sequential selection under tropical conditions, a genetic-trend analysis of growth traits was conducted in two Brahman herds in which a selection program had been designed and supervised within a research program. Herd A is a registered Brahman herd owned by the Facultad de Ciencias Veterinarias Universidad Central de Venezuela and located at the La Cuirtaca Experiment Station. Herd B is a privately-owned registered Brahman herd located in the state of Portuguesa in a tropical climate with mean annual rainfall of 1,652 mm. Replacement bulls were selected mainly on 18-mo weight and the result of their semen test. The rigid selection programs have improved genetic and phenotypic growth rates and reproductive efficiency. Sequential selection using individual and progeny performance data has proven adequate for genetic improvement of Brahman cattle under tropical conditions.
