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Feed Efficiency in Growing and Mature Animals
Interest in efficiency of production, particularly feed efficiency, is intensifying. Many definitions of feed efficiency exist in growing and mature animals although most research on feed efficiency is on growing animals. Here we review the state of the art on the alternative definitions of feed efficiency, their genetic component, and discuss how such measures could be included in breeding goals. Selection index theory in growing beef cattle suggests an improvement in monetary response to selection for a terminal-based breeding goal of up to 20%, if measures of feed intake are available on the animal itself or a small number of progeny. The corresponding response to selection was considerably less (≤5%) in mature dairy cows assuming feed intake was available on sires measured as growing bulls, and a genetic correlation of 0.67 existed between residual feed intake in a growing animals and lactating animal.
Keywords:
heritability
definition
breeding goal
