In vivo ultasonic measurements and live weight for predicting carcass quality in Churra Tensina mountain breed lambs

Abstract

Forty-six single male lambs ofChurra Tensina mountain breed with a live-weight ranging from 19.9 . to 24.4 kg ('Temasco' carcass commercial type) were scanned by ultrasound (ALOKAmodel SSD- 900, with a 7.5 MHz probe) to determine M. longissimus dorsi depth and subcutaneous fat thickness between the lOth-lith, 12th-13th dorsal vertebrae and 1st-2nd, 3rd-4th lumbar vertebrae. Lambs were slaughtered and carcasses were cooled at 4 °C for 24 h and halved. The left side was divided according to a standardised jointing procedure, based on six anatomical regions: shoulder, long leg, anterior ribs, ribs, flank and neck. Each joint was then disseCted into ,muscle, bone plus remainder and subcutaneous, inter-muscular, kidney and pelvic fat. Thein vivo ultrasound measureme~ts plus slaughter weight were fitted to predict carcass tissue composition by Stepwise regression analysis. All the developed models were highly significant (P<O.OO 1) and explained 70, 51 , 82, 56, 59 and 41 % of the muscle, bone plus remainder, subcutaneous, inter-muscular, kidney and pelvic fat variation respectively. The model residual standard deviations were lower than 124.3 g.