Replacement of dietary corn with corn bran plus condensed distillers solubles effects on feedlot growth performance and carcass trait responses of beef steers

Abstract

Dry corn milling biorefineries have the opportunity to install technology to fractionate corn prior to fermentation which creates a product stream of fibrous bran that can be fed to cattle. The objective of this study was to determine the effects of replacing dietary corn with corn bran and condensed distillers solubles (CBCDS) or wet corn gluten feed (WCGF) on growth performance, efficiency of dietary net energy (NE) utilization, and carcass characteristics in finishing steers. British × Continental steers (n = 240; initial BW = 401 kg ± 43.2 kg) were assigned to the following dietary treatments in a randomized complete block design (RCBD): 1) a Control finishing diet with no corn milling co-products 2) a finishing diet that contained CBCDS at 20% replacement of dietary corn 3) a finishing diet that contained WCGF at 20% replacement of dietary corn. Dietary corn (50:50 of dry rolled corn and high moisture corn) was included at 81.5% for control diet fed steers and 61.5% for steers fed CBCDS and WCGF. Steers were fed for 145.5 d until visually appraised to have 1.27 cm of rib fat (RF) and harvest at a commercial abattoir where carcass data was collected. Data was analyzed as an RCBD with pen as the experimental unit, treatment as a fixed effect and block as a random effect. There were no significant differences (P ≥ 0.28) between treatments for final body weight (BW), average daily gain, dry matter intake, feed conversion efficiency, observed dietary NE for maintenance (NEm) and NE for gain (NEg), or observed-to-expected NEm and NEg. Additionally, no differences (P ≥ 0.16) were noted between treatments for hot carcass weight, ribeye area, RF, marbling score, kidney-pelvic-heart fat, estimated empty body fat (EBF), BW at 28% EBF (AFBW), and distribution of USDA Quality and Yield grades. Control steers tended (P = 0.10) to have the highest calculated yield grade (YG) followed by WCGF and CBCDS. Furthermore, WCGF steers tended (P = 0.08) to have the highest calculated retail yield (RY) followed by CBCDS and Control steers. Replacement NEm and NEg values of corn co-products were determined to be 2.14 and 1.42 for CBCDS and 2.09 and 1.37 for WCGF respectively. Thus, CBCDS can be included in finishing steer diets at 20% replacement of corn without detriment to growth performance or carcass characteristics.