Submitted to: American Meat Science Association Conference Reciprocal Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: April 9, 2008
Publication Date: June 22, 2008
Citation: Shackelford, S.D., Ferrell, C.L., King, D.A., Wheeler, T.L., Koohmaraie, M. 2008. Effects of distillers grain on beef carcass quality and tenderness [abstract]. Proceedings Reciprocal Meat Conference. Suppl. 1:31. Technical Abstract: A study was conducted to determine the effect of feeding wet distillers grain with solubles (WDGS) during the finishing phase on beef carcass quality and ribeye steak tenderness. Crossbred beef steers (n = 304) received finishing diets including 0, 20, 40, or 60% WDGS on a dry-matter basis. Steers were implanted with Synovex-S during the growth phase and Revalor-S at initiation of the WDGS trial. Steers were blocked and penned in such a manner as to facilitate optimal marketing of the steers in four groups with the length of the finishing trial differing between blocks (98 to 113 d). An equal number of steers assigned to each level of WDGS were harvested at each time point. Cattle were harvested at a large scale commercial packing plant and the carcasses were electrically-stimulated and chilled conventionally. At approximately 32 h postmortem, carcasses were ribbed and carcass grade traits were evaluated for each carcass side with VBG2000 beef carcass grading image analysis system. Quadratic effects (P < 0.0001) of WDGS level were observed for carcass weight (HCW), preliminary yield grade, adjusted preliminary yield grade (ADJ), and yield grade (YG) such that carcasses of cattle fed 20% WDGS were heavier, fatter, and had higher YG than cattle fed 0% WDGS with carcasses of cattle fed 40% WDGS being intermediate to 0% and 20% WDGS. Carcasses of cattle fed 60% WDGS were lighter, less fat, and had lower YG than all other treatments (P < 0.05). Consistent with the HCW difference between diets, ribeye area (REA) was lower for 60% WDGS than all other diets (P < 0.05). Marbling score (MS) and percentage of carcasses grading Choice or higher (PC) was lower for cattle fed 60% WDGS than all other diets (P < 0.05). Ribeye lean color L* values were lower for 60% WDGS carcasses than all other diets (P < 0.05) and the percentage of carcasses classified as dark cutters (DC) was higher for 60% WDGS than all diets except the control (P < 0.05). Level of WDGS did not affect longissimus slice shear force (SSF) values at 14 d postmortem (P > 0.05). Clearly, there are economic advantages to use of WDGS in feedlot cattle rations. The undesirable impact of 60% WDGS on carcass merit suggests that either levels should be limited to a maximum of 40% or that perhaps 60% WDGS should only be used in growing rations. There may be merit to pursuing research of a variety of scenarios whereby cattle are fed high WDGS levels in the growing phase and then levels of WDGS are reduced during the finishing ration to optimize production efficiency with carcass value.