Application Of A Real-time Linear Array Ultrasound System To The Evaluation Of Live Cattle

A real time linear array ultrasound machine was assessed for bias accuracy and precision. A total of 51 heifers, and steers were scanned for fat thickness over the longissimus muscle, the shoulder and rump; for M. longissimus area between the 12th and 13th ribs; and marbling was subjectively evaluated from M. longissimus scans. Ultrasound data were compared with a live judging committee estimates and with carcass values obtained during USDA grading. Data adjusted for live weight were analysed by correlation and regression techniques. Ultrasound estimates of fat thickness were lower (P<.01) than carcass measurements. Shoulder fat thickness estimation was the lowest in precision and accuracy. The residual standard deviations of ultrasound estimates of fat thickness were not (P>.05) influenced by fat thickness and sex. Ultrasound estimates of M. longissimus area were not different (P>.05) from carcass values and were high in precision (RSD: 2.6 to 6.5cm2). The precision and accuracy of data collected by real time linear array ultrasound system indicate a potential for the application of the ultrasound technique to grading of livestock and carcasses.