Feedlot Performance and Composition of Gain in Late-Maturing Steers Exhibiting Normal and Compensatory Growth

Abstract

The relationship between body weight, rate of gain and composition of gain was studied in 23 late-maturing steers, from 200 to 550 kg empty body weight (EBWT), exhibiting normal and compensatory growth. Body composition was estimated at 60- to 75-kg intervals of empty body weight gain (EBWG) using a deuterium oxide dilution method. Steers realimented after a 70-d period of live weight constancy exhibited compensatory growth that was associated with a leaner composition of gain in comparison with those that had been fed to grow continuously. At approximately 300 kg EBWT, steers realimented from approximately 200 kg began to exhibit normal growth patterns. Composition of gain was influenced by both EBWT and EBWG. Increasing EBWG resulted in significant increases in protein deposition rates. On the other hand, increasing EBWT was concomitant with decreasing protein deposition rates. Fat deposition rates increased with increasing EBWG and EBWT. Because steers of late-maturing genotypes have a high potential for protein deposition and are not inclined to deposit fat, their utilization on feeding systems based on low energy diets may be limited.