Evaluation of USDA feeder calf grades and health status of steers and their impact on live and carcass performance in south Texas

Abstract

In 2003-2004, the Texas A&M University Ranch to Rail South program evaluated 430 steers in Edroy, TX. Data were analyzed on several traits, but feeder calf frame and muscle grades and health status were emphasized. Muscle thickness grade (M), frame size grade (F), muscle thickness by frame size interaction (M*F), sire breed type classification (SIRECODE), lung score (LUNG), ranch of origin (RANCH), and level of treatment (LVLTRT) were evaluated as independent variables as affecting ribeye area (REA), marbling score (MARB), fat thickness (FAT), hot carcass weight (HCW), average daily gain (ADG), medicine costs (MED), days on feed (DOF), initial value (VALUE), carcass value (CARVAL), and initial weight (INWT). M (P < .0001), F (P < .0001), M*F (P < .0001), SIRECODE (P < .0001), RANCH (P < .0001), LVLTRT (P = .0016), and INWT (P < .0001) were all significant influences on initial value upon arrival. SIRECODE (P = .0344), RANCH (P = .0571), and INWT (P < .0001) were significant in impacting carcass value. RANCH (P = .0045) and INWT (P < .0001) were very significant influences upon ribeye area when the steers were harvested. RANCH (P < .0001) was also influential on marbling score, and LVLTRT (P = .1096) was slightly significant for MARB. M (P = .0659), F (P = .0721), and M*F (P = .0722) were moderately significant in influencing fat thickness. However, SIRECODE (P = .0148) and RANCH (P < .0001) were significant in impacting FAT. HCW was significantly affected by SIRECODE (P = .0056), RANCH (P < .0001), and INWT (P < .0001). For live performance, SIRECODE (P = .0120) and RANCH (P < .0001) were significant influences upon average daily gain. SIRECODE (P < .0001), RANCH (P < .0001), LVLTRT (P < .0001), and INWT (P < .0001) were significant influences on days on feed for the steers. Finally, RANCH (P < .0001) and LVLTRT (P < .0001) were significant in affecting medicine costs. These findings suggest ranch of origin and breed type play major roles in affecting live and carcass performance.