THE PREDICTION OF BEEF CARCASS LEAN CONTENT BY AN ELECTRONIC PROBE, A VISUAL SCORING SYSTEM AND CARCASS MEASUREMENTS

Abstract

Five hundred and thirty-one beef carcasses were used to establish if Hennessy Grading Probe (HGP) measurements provided a more accurate assessment of carcass lean content than a visual scoring system or linear carcass measurements. Carcasses were probed at the 5th/6th, 11th/12th, 12th/13th ribs, 2nd/3rd lumbar and sacral crest position (P8). Carcasses were then visually appraised for overall fat cover and muscle thickness. Following 24 h of cooling, the measurements by HGP and visual scores were repeated. Fat thickness and loin eye area were recorded at the 12th rib. Precision for the prediction of carcass lean by HGP was similar in warm or cold carcasses and the lowest error of prediction for the probe was associated with measurements made at the 12th/13th rib (RSD 31.8 g kg −1 ). A combined visual score for overall fat cover and muscle thickness was more precise (RSD 28.6 g kg −1 ) than probe measurements for predicting lean yield in warm and cold carcasses. Canada grade had the lowest precision (RSD 34.7 g kg −1 ) for predicting lean yield, but measurements of average fat thickness and loin eye area at the 12th rib gave the best overall prediction (RSD 27.1 g kg −1 ) of carcass lean content. It was concluded that the HGP provided a method to classify warm carcasses for lean content, but the improvement in precision over conventional grading procedures was not large. Key words: Beef, carcass, grading, Hennessy grading probe, composition