Trends of performance in Arkansas cooperative beef-bull performance tests from 1962 through 1982.
Individual records of performance of 2787 bulls in cooperative beef-bull performance tests from 1962 through 1982 were analyzed to determine trends in final weight, average daily gain, daily feed consumption and gross feed efficiency. Data from Angus, Polled Hereford, Charolais, Hereford and Santa Gertrudis breeds were analyzed separately. Performance-test procedures and the ration fed remained the same in all tests. Least-squares means by year, adjusted for location of test, initial weight, initial age and initial condition score, were regressed on time to determine average yearly change in the traits. Yearly changes for Angus, Polled Hereford, Charolais, Hereford and Santa Gertrudis breeds in final weight were 3.3, 1.6, 3.3, 2.5, and 2.6 kg, respectively; in average daily gain and yearly changes were .02, .01, .02, .02, and .02 kg, respectively; in daily feed consumption the yearly changes were .08, .03, .09, and .04 kg, respectively; and in feed per kg gain the yearly changes were -.08, -.04, -.05, -.03, and -.07 kg, respectively. Because the test procedures were the same in all years, these trends represent genetic progress made by the Arkansas beef industry toward faster-gaining, more efficient cattle.