EFFECTS OF TREATING SORGHUM WET DISTILLER’S GRAINS WITH SOLUBLES WITH AN ENZYME COMPLEX ON NUTRIENT DIGESTIBILITY AND PERFORMANCE IN FINISHING BEEF STEERS

Two experiments were conducted to determine the effects of treating sorghum wet distiller’s grains with solubles (SWDGS) with an enzyme complex, or enzyme complex-buffer combination on diet digestibility and feedlot performance. Experimental treatments were as follows; 1) untreated SWDGS (Control), 2) addition of an enzyme complex to SWDGS (Enzyme); and 3) addition of enzyme complex and limestone buffer to SWDGS (E+B). Sorghum WDGS, regardless of treatment, was included at 45% DM (DM basis) of a steam-flaked corn-based finishing diet. The enzyme complex (Biozyme, Inc., St. Joseph, MI) was a proprietary blend containing both exogenous and endogenous hemicellulase, cellulase, and amylase enzymes, and was added at rate of 6 L/dry ton and 6.2 L/dry ton of SWDGS in Experiment 1 and 2; respectively. In the first experiment, six crossbred beef steers (initial BW = 577 ± 6.9 kg) were used to evaluate the effects of treating SWDGS with an enzyme complex or buffered enzyme complex on digestibility of nutrients. No differences (P > 0.28) in DMI, or digestibility of DM, OM, and starch between treatments were detected. Steers fed E+B treatment had higher (P = 0.07) ruminal pH than Control or Enzyme steers. Neutral detergent fiber digestibility tended (P = 0.15) to be greater for E+B fed steers. In a second experiment, 54 beef steers (initial BW = 370 ± 9 kg) were fed in a finishing study evaluating the same dietary treatments as the first experiment. No difference (P > 0.31) in DMI, ADG, or G:F was detected for the entire feeding period when Enzyme fed cattle were compared to Control. In contrast to the first experiment, DMI for the feeding period was lower (P = 0.03) for E+B fed cattle compared to Enzyme. There was no difference (P = 0.39) in ADG during the entire feeding period between Enzyme and E+B fed cattle; however, G:F was greater (P = 0.05) for E+B fed cattle compared to Enzyme. Standard carcass measurements did not differ (P > 0.43) between Enzyme and Control treatments. Most standard carcass measurements did not differ (P > 0.42) between E+B and Enzyme treatment, however, E+B cattle had less rib fat (P = 0.05) and had lower (P = 0.02) yield grades. Furthermore, the E+B fed cattle tended to have (P = 0.06) larger ribeye areas than Enzyme cattle. In conclusion, while treating SWDGS with a buffered enzyme complex containing primarily fibrolytic enzymes effects had positive on NDF digestibility, no corresponding improvements in cattle performance were detected.