Prediction of carcase fat depth in live lambs: a comparison of techniques

Abstract

The accuracy of condition scoring, the Scanogram and Scanoprobe for the prediction of carcase fat depth in live lambs was examined in 99 crossbred ewe lambs. The Scanogram was the most accurate predictor of fat depth at site C (12-13th rib junction, 40 mm from the dorsal midline), and soft tissue depth at site J110 (12-13th rib junction, 110 mm from the dorsal midline) in the carcase [residual standard deviations (RSD) of 1.1 67 and 2.166 mm, respectively]. The accuracy of the Scanogram in predicting carcase fat depth depended on variation in liveweight (P < 0.05). Condition scores were the next best predictors of measurements at sites C and J110 in the carcase (average RSD for three operators of 1.324 and 3.174 mm, respectively). The accuracy of condition scores by the best operator (i.e., the most repeatable and accurate) was largely independent of variation in liveweight. Condition scores were related (P < 0.05) to all carcase dimensions, although a general trend for the three operators was for condition scores to have the strongest relation with soft tissue depth at site J110 and then fat depth at site C, followed by the carcase classification fat score and lastly total tissue depth at site C. The Scanoprobe was the poorest predictor of C and J110 measurements in the carcase (RSD = 1.630 and 4.014 mm, respectively).