Effects of Lubabegron Supplementation of Conventional Feedlot Heifers on Steak Dimensionality, Shear Force, and Trained Sensory Evaluation

Lubabegron fumarate (LUB) is a β-agonist developed for the reduction of ammonia emissions in beef cattle. Heifers (n = 106) were fed LUB for 56 d before harvest, and a contemporary group of heifers was identified. Heifers were traced through harvest, and a subsample of carcasses grading USDA Choice (Small00–Moderate99) was selected, and strip loins were collected from these carcasses. Loins were then fabricated into 2.54-cm steaks, and 3 steaks were assigned to each aging period: 7, 14, 21, 28, or 35 d, aged, then frozen. Steaks were then subject to the following analyses: steak dimensionality, slice shear force (SSF), and trained panel evaluation. Data were analyzed as a split-plot design, with LUB treatment serving as the main plot factor, and aging period serving as the subplot factor. Steaks from the LUB treatment were larger in area at 7 of 11 steak positions (P < 0.05), although they were not different for length at any position (P > 0.05). Additionally, LUB steaks were wider at 40.9% of measured locations across the loin (P < 0.05). Moreover, trained panelists detected no differences among all palatability characteristics among treatments or aging periods (P > 0.05). Steaks from the LUB treatment resulted in greater SSF values at 7, 14, and 21 d aging compared to the control at the same days of aging (P < 0.05). These results indicate that while statistically significant increases in tenderness are detectable by slice shear force, trained panelists did not detect the same differences. Therefore, the overall impact of LUB on overall palatability in the current study is minimal.