Effectiveness of using ultrasound readings to predict carcass traits and sensory quality in young bulls

•Using ultrasound readings to predict beef quality of young lean bulls was tested.•Early ultrasound reading during fattening to predict fat beef content is recommended.•Sensory fatty flavor of beef could be predicted using ultrasound measurements.•Ultrasound testing in the feedlot offers promising potential to predict beef quality. The objectives of this study were to develop ultrasound-derived prediction equations in young bulls before slaughter to estimate carcass traits and beef sensory parameters and to determine the optimum moment pre-slaughter to estimate the sensory quality of beef from young bulls. Ultrasound images were measured in twenty live young bulls at 50, 25 and 1 days prior to slaughter. Intramuscular fat content, longissimus lumborum muscle area, carcass fatness, texture and sensory analysis were measured by a trained panel after slaughter. Partial least square methodology was used to find the relationship between the ultrasound measurements and the dependent variables, such as carcass traits, Warner-Bratzler shear force and the sensory profile. Additionally, a stepwise procedure was used to select the most informative ultrasound variables in the prediction equations for carcass and beef sensory traits. The results indicate that ultrasound testing in the feedlot offers promising potential. Early ultrasound scan measurements were useful during fattening to predict intramuscular fat content (R2 = 0.619, RMSE = 0.44%, 50 days prior to slaughter), while ultrasound scans taken close to slaughter were useful to predict kidney fat content (R2 = 0.717, RMSE = 0.96%, 1 day prior to slaughter). However, the prediction of sensory beef attributes was only useful for fatty flavor (R2 = 0.556, RMSE = 0.47%) at 1 day pre-slaughter. Thus, the prediction of fat parameters using ultrasound measurements could constitute a valuable tool in the process of selecting beef quality traits in young bulls before slaughter.