Groschke, David Wayne (2005-08). Evaluation of USDA feeder calf grades and health status of steers and their impact on live and carcass performance in south Texas. Master's Thesis. Thesis uri icon


  • 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.

publication date

  • August 2005