346 Substitution of Modified Distillers Grains with Soybean Meal with Or Without Hulls Had Negligible Effect on Growth Performance, Efficiency and Carcass Traits in Yearling Steers

Abstract

Abstract Changes to the fuel landscape in the United States have resulted in changes in long-held supplemental protein price relationships. The objective of this study was to evaluate substituting oilseed meal for corn processing co-products. Predominately Angus steers [initial shrunk body weight (BW) = 435 ± 23.6 kg] were used in a 118-d experiment using three treatments: modified distillers grains (MDGS)fed at 15% diet DM (MDGS) replaced by either soybean meal and corn (9 and 6% of DM, respectively; SBM), or soybean meal and soyhull pellets (9 and 6% of DM, respectively; SBM-SBH). Steers (n = 240) were individually weighed and allotted to one of 24 pens (n = 10 steers per pen; 8 pens per treatment) at the Southeast Research Farm located near Beresford, SD. Dietary concentrations of crude protein and neutral detergent fiber based on tabular values and weekly batching records were 12.3 and 17.6%, 12.8 and 14.5%, and 12.8 and 17.8% for MDGS, SBM, and SBM-SBH, respectively. Data were analyzed as a randomized complete block design using the GLIMMIX procedure of SAS 9.4 with treatment and block as fixed effects; pen was the experimental unit. Pen conditions were wet and muddy during the final weeks of this experiment; consequently, final BW was calculated by dividing hot carcass weight (HCW) by a common dressing percentage of 62.5. No differences amongst treatments (P ≥ 0.11) were found for carcass-adjusted final BW, dry matter intake (DMI), average daily gain (ADG), or feed efficiency. Dietary treatment had no effect (P ≥ 0.11) on HCW, dressing percentage, ribeye area, rib fat, marbling score, USDA Yield Grade, percent empty body fat (EBF), or final BW adjusted to 28% EBF. Distribution of USDA Quality and Yield grades were unaffected by treatment (P ≥ 0.39). Dietary treatment did not affect liver abscess incidence and severity (P = 11). Net energy values calculated from animal performance agreed closely with tabular estimates with observed to expected ratios for net energy equaling one. In this experiment, feeding supplemental protein sources with enhanced diet conditioning attributes and greater concentrations of ruminally undegradable protein provided no advantage to cattle performance. These results indicate that protein source decisions can be based upon price per unit of delivered crude protein.