Effects of feeding high-oil corn to beef steers on carcass characteristicsand meat quality

To assess the effects of feeding high-oil corn on carcass characteristics a nd meat quality, 60 yearling steers were fed high concentrate diets contain ing either control corn (82% of diet), high-oil corn (82% of diet), of high -oil corn at a concentration that was isocaloric with the control diet (74% of diet). After being fed for 84 d, steers were slaughtered. At 72 h postm ortem, carcass data were collected and rib sections from five steers gradin g U.S. Choice and five steers grading U.S. Select from each treatment were collected, vacuum packaged, and aged for 14 d. Three steaks (2.54 cm thick) were removed from each rib for Warner-Bratzler shear force measurement, se nsory appraisal, and fatty acid composition analyses. Data were analyzed wi th treatment as the main effect for the carcass data and treatment, quality grade, and two-way interaction in the model for the longissimus data. The two-way interaction was nonsignificant (P > 0.05) for all variables tested. No differences were detected (P > 0.05) in carcass measurements except for marbling scores and quality grades, both of which were greater (P < 0.05) for carcasses from steers fed the high-oil corn. Overall, 78% of steers fed the high-oil corn graded U.S. Choice compared with 47% for the control and 67% for isocaloric group. Shear force and sensory properties of the longis simus were not different (P > 0.05) among treatments. Steaks from U.S. Choi ce carcasses rated higher (P < 0.05) for tenderness and tended to rate high er (P < 0.10) for juiciness. Feeding the isocaloric and high-oil diets incr eased (P < 0.05) linoleic acid, arachidonic acid, and the total PUFA conten t of lipid extracted from the longissimus. Saturated fatty acid percentage was lowest (P < 0.05) for high-oil corn and highest (P < 0.05) for control, with isocaloric being intermediate. Feeding high-oil corn increased (P < 0 .05) pentadecyclic acid, margaric acid, and total odd-chain fatty acid cont ent. Feeding high-oil corn in finishing beef cattle diets enhanced intramus cular lipid deposition and increased unsaturation of fatty acids of the lon gissimus.