Effects of Time of Supplementation on Beef Stocker Calves Grazing Ryegrass. I. Performance and Economic Analysis1

An opportunity for improving the profitability of beef production in the Southeast lies in stockering weaned calves on high-quality, cool-season annual or perennial pastures. The large supply of weaned calves available in this region offers the opportunity for businesses to concentrate on stockering systems and retained ownership. Optimized nutrient utilization for these forage-fed cattle can be through the timing of supplementing nutrients within a day. In each year of this consecutive 2-yr experiment, 72 crossbred steers (initial BW = 227.6 ± 0.6 kg) weaned in October were blocked by BW and biological type into 12 groups, which were later allotted to one of the following treatments (3 replicates): 1) control, nonsupplemented; 2) morning (0700 h) supplementation with 0.5% BW of corn gluten feed (CGF); 3) noon (1200 h) supplementation with 0.5% BW of CGF; or 4) afternoon (1600 h) supplementation with 0.5% BW of CGF. Steers were weighed at 14-d intervals and supplementation level was adjusted accordingly. Forage mass, height, and nutritive value were estimated every 14 d. Differences in ADG (P < 0.05) were detected in the first 60 d of the grazing period, although no differences existed when the whole experimental period (105 d) was considered. Even though consumption of CGF did not differ among supplemented treatment groups, there was a significant positive impact (P = 0.042) on kilograms produced per hectare when morning supplementation was compared with noon supplementation. Ruminal environment may have been affected since forage variables and ADG were not different across timing of supplementation. Under the conditions of this experiment, supplementation did not enhance animal performance, beef production per hectare, or profitability. However, noon supplementation may be detrimental to these aspects in a winter grazing enterprise.