Six ultrasonic fat and muscle depth measurements, taken on the left and the right side of the fourth lumbar vertebra and third stemebra of the breast bone, were related to carcass composition to determine the accuracy of these measurements for predicting
carcass compositon of live Aragdn lambs (Temasco) . Live weight alone accounted for 21, 19,26, 18 and 47% of total variation
of muscle, bone plus remainder, total fat, and subcutaneous and intermuscular fat, respectively. Addition of ultrasonic fat depth
measurement on the right side of the lumbar region accounted for a further 18,31,33 and 36% of muscle, bone plus remainder,
total carcass fat and subcutaneous fat, respectively. Addition of the same measurement taken on the left side accounted for a
further 15% of intermuscular fat. Live weight alone accounted for only 4% of the total variation of kidney and pelvic fat, but the
addition of ultrasonic fat depth measurement on breast bone accounted for a further 26% of the variation of this fat depot. The
accuracy of prediction of carcass composition on live animals could be improved by the addition of ultrasonic fat measurements.
