194 A Systems Approach to Deriving Carcass Value from Holstein x Simangus Cattle in an Accelerated Finishing Model

Abstract

Abstract Crossbreeding dairy cows with beef sires has increased in the U.S. dairy industry. This beef x dairy mating results in dairy-beef which has altered the U.S. fed beef supply. The predominant mating has been Holstein x Angus, thus research was conducted to determine the effects of Holstein x SimAngus breeding on growth performance, carcass characteristics, and fresh meat quality. Starting on d 1, Holstein steers (n = 9) and Holstein x SimAngus (HolSim) steers (n = 12) were fed once daily at 0830 h, until an end weight of 635 kg was reached. Holstein steers averaged 421 d and HolSim steers averaged 432 days on feed. Daily feed offered was delivered into a semi-autonomous feed monitoring system designed to measure individual animal intake and feeding behavior (GrowSafe System Ltd). Steer body weight was recorded every 28 d. Data collected were used to calculate dry matter intake (DMI), average daily gain (ADG), and gain to feed ratio (G:F). Steers were humanely slaughtered under USDA inspection, immediately following slaughter hot carcass weight (HCW) was recorded and 48 h following slaughter, carcass length, body width, backfat thickness and area of the longissimus muscle (LM) was recorded. Strip loins were collected from each carcass and aged for 14 d. After aging, Warner-Bratzler shear force (WBSF) and slice shear force (SSF) were determined. Remaining steaks were placed under retail display for 7 d. Objective color was measured after 0, 1, 3, 5, and 7 d in retail display. No differences were observed for ADG and G:F between Holstein and HolSim steers (P > 0.05). A tendency was observed for Holstein steers to have a greater DMI compared with HolSim steers (P = 0.0646). The HolSim steers had greater HCW and dressing percentages compared with Holstein steers (P < 0.0001). The HolSim carcasses had shorter carcass lengths and body widths compared with Holstein carcasses (P = 0.0005). Holstein carcasses had less backfat compared with HolSim carcasses (P = 0.0034). The LM area was larger in HolSim carcasses (P < 0.0001). No differences were observed for WBSF or SSF (P > 0.05). Strip steaks from HolSim steers had less deoxymyoglobin and greater oxymyoglobin values on d 0 of retail (P < 0.05). Strip steaks from HolSim steers had greater a* and saturation index values on d 7 in retail (P < 0.05). Strip steaks from HolSim steers had decreased metmyoglobin values and greater oxymyoglobin values on d 7 in retail (P < 0.05). Thus, indicating strip steaks from HolSim steers had increased red color. Growth performance data in this study confirm previous literature reported when comparing dairy x dairy to beef x dairy steers. Carcass and fresh meat data suggest that Holstein x SimAngus steers had improved yield production compared with Holstein steers without a loss in quality when steers were fed to a weight constant end point.