This study wasconducted to evaluate the use of ultrasound measurements to predict carcasscomposition of 115 steers (Nellore, ½ Angus x Nellore, ½ Simentalx Nellore, and Canchim) with different frame sizes (small and large) and averageinitial body weight of 329 kg. After 120 days in a feedlot, animals were weighedfollowed by ultrasound measurements of rib eye area (RA) and fat thickness (FT).Animals were slaughtered and measurements of carcass RA and FT, weights of hindquarter,forequarter, and commercial cuts, and determination of body composition weredone. In addition, yields of carcass, commercial cuts, and hindquarter werecalculated and no significant differences between frame sizes were found forthese variables. Ultrasound measurements were not precise predicting carcassmuscle content and yields of commercial cuts in this trial. However, determinationcoefficients from regression equations of carcass composition using ultrasoundwere similar and sometimes higher (e.g. bone content) than those from regressionequations of carcass composition, in which measurements were taken after slaughter.Therefore, ultrasound measurements can be used to predict carcass compositionof beef cattle for some variables.
