70. Inclusion of Whole Cottonseed in Successive Backgrounding and Finishing Phases in Beef Cattle: A Backgrounding Summary

Abstract Whole cottonseed (WCS) is a valuable byproduct of the cotton industry and a common supplement in beef cattle diets due to its high energy and fiber content. However, data from its inclusion in multiple successive phases of cattle production are lacking. Thus, our study was designed to evaluate WCS inclusion in both the backgrounding and finishing phases of beef cattle production. Steers (n = 48; initial BW = 287 ± 3.6 kg) were stratified by initial body weight into groups and randomly assigned to replicate signalgrass (Urochloa spp.) pastures at the E. V. Smith Research and Extension Center. Pastures (n = 12; 1.0 ha) were then randomly allocated to one of three treatments for an 84-d backgrounding period: non-supplemented control (SUPP-C); 0.5% BW WCS supplementation (SUPP-L); or 1.0% BW WCS supplementation (SUPP-H). Forage samples were collected every 14 d, and steers were weighed every 28 d. There was no effect of treatment (P = 0.98) on steer BW in the backgrounding period. There was, however, an effect of treatment (P = 0.01) on ADG. Steers from SUPP-H had the greatest ADG (0.36 kg/d) and those from SUPP-C the least (0.12 kg/d), with SUPP-L intermediate (0.27 kg/d). While these results align with our hypothesis that increased WCS supplementation would result in improved steer performance, all ADG were less than would be targeted in optimum production. One explanation for our results could be the forage base used in the experiment. While forage mass was not limiting (3,595 kg/ha), signalgrass is a warm-season perennial grass known to have low nutritive value. Results are interpreted to mean that WCS can be an effective supplement for steers grazing warm-season forages in the backgrounding phase.