A study on the variation of feed efficiency in station tested beef bulls

The records of 282 young beef bulls from eight breeds tested from November 1981 to April 1987 at the Ellerslie Bull Test Station, Alberta, Canada, wer e used to study the variation in feed efficiency among young performance-te sted bulls. Considerable variation existed among the animals in both residu al metabolizable energy consumption and residual dry matter consumption. Th e heritability estimates for residual metabolizable energy consumption and residual dry matter consumption were 0.33 and 0.29, respectively. In additi on, residual metabolizable energy consumption and residual dry matter consu mption were moderately correlated (r = 0.43) with conventional feed-to-gain ratio, indicating that conventional feed-to-gain ratio only accounted for 18% of the variation in residual metabolizable energy consumption or residu al dry matter consumption. It was, therefore, worthwhile to use residual me tabolizable energy consumption or residual dry matter consumption as separa te measures of feed efficiency. For rapid improvement in feed efficiency in beef cattle, selection pressure should be applied to both growth traits an d residual energy consumption or residual dry matter consumption. Multi-tra it optimum restricted selection indices and similar selection procedures ma y serve as useful means in balanced selection programs to improve the produ ctivity of beef cattle.