Residual Feed Intake and Feed Efficiency: Differences and Implications

In the beef production system, 70-75% of the total dietary energy is used for maintenance (Ferrell and Jenkins 1984; NRC 1996; Montaldo-Bermudez et al. 1990). Thus, while only 5% of the total life cycle dietary energy consumption is used for protein deposition in beef cattle, swine and poultry are more efficient at 14 and 22%, respectively. The relatively large size, slow maturity and slow reproductive rates of cattle ( Pitchford et al. 2002), are some of the major reasons for the inefficiency of beef production. However, maintenance energy requirements of cattle are moderately to highly heritable (h = 0.22-0.71), suggesting an opportunity to select for more efficient cattle (Carstens et al. 1989; Bishop 1992). Thus, improvements in the efficiency of use of maintenance energy either through selection, nutritional considerations and/or through management strategies should result in an increase in total beef production for a given amount of feed.