Use of soybean hulls with or without corn by-product protein sources in feedlot backgrounding diets

Grain and oilseed by-products are potential feedstuff alternatives to grains and oilseed meal in feedlot diets. Two hundred newly weaned Angus steer calves (BW = 268 ± 25 kg) were used to evaluate the replacement of dry-rolled corn (starch-based energy; DRC) with soybean hulls (fiber-based energy; SBH), and soybean meal (SBM) with corn by-products on feedlot backgrounding performance. Steers received oat silage-based diets containing DRC plus SBM (C-SBM), SBH plus SBM (H-SBM), SBH plus dried corn gluten feed (H-DCGF), or SBH plus dried distillers grains with solubles (H-DDGS) for 52 d. Compared with C-SBM, H-SBM steers had greater (P < 0.05) DMI during the initial 28 d and overall but no differences (P > 0.10) in ADG or G:F. No differences (P > 0.10) were detected for DMI, ADG, G:F, glucose, or nonesterified fatty acids when comparing H-SBM steers with steers receiving corn-origin protein (mean of H-DCGF and H-DDGS). The H-SBM steers had greater (P < 0.05) urea nitrogen concentrations on d 28 and 52 compared with steers on corn-origin protein diets, indicating potentially greater protein degradability. Compared with H-DCGF steers, H-DDGS steers had greater (P < 0.05) ADG during the initial 28 d but were similar (P > 0.10) overall. The H-DCGF steers had greater (P < 0.05) concentrations of glucose and nonesterified fatty acids on d 28 compared with H-DDGS steers but were otherwise not different (P > 0.10). Based on performance and blood metabolites, SBH with or without corn by-products can be a substitute for DRC and SBM in feedlot backgrounding diets.