Richeson, John2015-03-232015-03-232014-122015-01-08December 2http://hdl.handle.net/11310/13Two 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.application/pdfen-USSWDGS, Enzymes, NDF Digestibility, CattleThesis2015-03-23