Digestible energy requirements for growth in Hereford and Charolais × Hereford steers

Abstract

The relationship between digestible energy intake (DEI) per day and growth in steers was investigated using data from 717 steers fed individually in several experiments. Regression equations relating DEI, gain and weight were obtained for medium-frame (Hereford) and large-frame (Charolais × Hereford) steers that had been fed all-concentrate or hay–concentrate diets under various feeding regimes from weaning to slaughter. The equations can be used as a guide for estimating DEI and gain and provide information on the efficiency of feed utilization. Estimates of the mean DEI for a given mean gain and weight of steers in a large commercial feedlot operation were similar to the observed mean DEI. Steers restricted in DEI for the first 24 wk of the feeding period (average initial weight of 213 and 257 kg for Hereford and Charolais × Hereford, respectively) generally utilized DE more efficiently than steers fed to appetite on a concentrate or hay–concentrate diet, but as market weight was approached, restricted steers required more DE for a given gain and weight than steers fed on concentrate ad libitum. Efficiency of DE utilization was lower when steers were at low weights and as they approached market weight. Key words: Steers, DE requirement, frame size