BRIEF COMMUNICATION: Variation in feed conversion efficiency in Holstein-Friesian heifer calves

摘要

Feed conversion efficiency (FCE) is a measure of an animal's ability to convert feed into product and is a major determinant of profitability in livestock production. This study evaluated two determinants of FCE in Holstein-Friesian heifer calves, growth rate and residual feed intake (RFI). The improvement in FCE, measured as feed intake per unit of liveweight gain (kg/kg), associated with increased growth rate is well known (see Archer et ah, 1999). It is measured when the energy costs of maintenance are relatively small compared to the energy intake that is partitioned into growth of animal tissues or lactation. This aspect of FCE may be captured in part through genetic improvement, notably in beef cattle, but less so in dairy breeds where selection on growth traits is not usually an objective.