The objective of this study was to determine how real-time ultrasound (RTU) measurements would compare with carcass measurements to predict the percentage of retail product from the four primals (PRP4P). Data were collected on market ready cattle (n=471). Traditional carcass measures collected were: 1) hot carcass weight (HCW), 2) 12–13th rib fat thickness (CFAT), 3) 12–13th rib ribeye area (CREA), and 4) percentage of kidney, pelvic, and heart fat (CKPH). Live animal ultrasound measures collected were: 1) scan weight (SCANWT), 2) 12–13th rib fat thickness (UFAT), 3) 12–13th rib ribeye area (UREA), 4) subcutaneous fat thickness over the termination of the biceps femoris in the rump (reference point) (URFAT), 5) depth of the gluteus medius below the reference point (URDEPTH), and 6) area of the gluteus medius anterior to the reference point (URAREA). A model to predict PRP4P was developed for both carcass and RTU measures. Significant measures (P < 0.001) for the carcass data were CFAT, CREA, and CKPH with a model R2 = 0.297. HCW was not a significant trait in the carcass data model (P = 0.171). Significant measures (P < 0.001) for the RTU data were SCANWT, UFAT, UREA, and URDEPTH with a model R2 = 0.448.
Iowa State University
Tait, Richard G. Jr.; Rouse, Gene H.; and Wilson, Doyle E., "Comparison of Ultrasound and Carcass Measures to Predict Percentage of Beef Retail Product from Four Primal Cuts—Final Report" (2004). Beef Research Report, 2003. 1.