Effects Of Lubabegron Supplementation Of Conventional Heifers And Holstein Steers On Beef Palatability

Lubabegron has been approved in cattle to reduce gas emissions, but limited research has been done to evaluate its effects on beef quality. Therefore, the objectives of these studies were to evaluate tenderness differences via instrumental determination and protein degradation, as well as dimensional changes to the Longissimus lumborum (LL) of conventional heifers and Holstein steers fed lubabegron. Additionally, this study aimed to determine the eating quality of conventional heifers fed lubabegron supplementation. USDA Choice striploins (n = 106) collected from conventional heifers fed lubabegron for 0 (control) or 56 d (LUB) and striploins (n = 212) across all USDA quality grades were collected from Holstein steers fed lubabegron supplementation for 0 (control), 28 d (LUB 28), 56 d (LUB 56), and 84 d (LUB 84). Striploins were fabricated into 2.54 cm steaks and aged for 7, 14, 21, 28, or 35 d. At the time of fabrication, steaks were imaged for dimensionality prior to packaging. Then, using a digital imaging software, steak area (distance around LL), steak length (from the medial to lateral end of LL), and steak widths (25%, 50%, 75%, and 87.5% of the length of LL muscle from the anterior end) were measured. All steaks were analyzed for slice shear force (SSF) with a subset assigned to desmin degradation and a subset of the heifers was assigned to sensory analysis. Generally, steaks from both conventional heifers and Holstein steers fed lubabegron for any amount of time exhibited greater surface area, length, and greater widths at every length (25%, 50%, 75%, and 87.5%) in all steaks. Slice shear force values for steaks from conventional heifers decreased as steaks were aged longer. Control steaks were more tender (P ≤ 0.01) at 7, 14, and 21 d in comparison to control steaks; however, at 28 and 35 d a difference did not exist between the control and LUB steaks. Slice shear force values for Holstein steers, regardless of lubabegron duration, resulted in steaks from treated Holstein steers being tougher (P < 0.01) than steaks from control Holstein steers, after 7 or 14 d aging postmortem. After 21 d aging, steaks from control Holstein steers and LUB 28 steaks SSF values were not different, but steaks from Holstein steers fed lubabegron longer (LUB 56 or LUB 84) were tougher (P < 0.05). At 28 and 35 d of aging, SSF values were not different among steaks from control or any duration of lubabegron supplementation. Steaks from heifers were not different for any trained sensory attribute (P ≥ 0.07), regardless of supplementation or aging period. For conventional heifers both intact and degraded band ratios of desmin were greatest at 35 d postmortem and the least at 7 d postmortem. Intact degraded desmin ratios were not different regardless of lubabegron supplementation (P ≥ 0.07). For Holstein steers, no difference was found for intact desmin regardless of postmortem age or lubabegron supplementation (P ≥ 0.48). Degraded desmin was greater (P < 0.01) for 35 d postmortem age compared to ratios from samples aged 7 d postmortem (P > 0.01), with 21 d postmortem being intermediate and not differing from either. The feeding duration of lubabegron did not affect degraded desmin. These studies showed the effect of feeding lubabegron on beef quality. Although a tenderness difference was determined in SSF in conventional heifers, it was undetectable to trained sensory panelists. The overall dimensionality of the steaks favors the supplementation of lubabegron. Overall feeding lubabegron to heifers is not detrimental to overall beef quality. Steaks from Holstein steers treated with lubabegron for any length of time had higher SSF values at early postmortem aging timepoints, but no differences were detected after 28 d. The overall dimensionality of the steaks favors the supplementation of lubabegron. Desmin degradation was not affected by lubabegron supplementation for conventional heifers or Holstein steers.

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