The use of ultrasonography to predict carcass composition in kids

The objective of this work was to analyse the use of ultrasounds to predict carcass composition in kids. Twenty kids from Serrana Portuguese local breed with a mean live weight of 12.6 ± 2.99 kg were scanned by ultrasonography to determine longissimus muscle depth (LD), subcutaneous fat thickness (SF) between the 12th and 13th vertebrae (D12), 1st and 2nd (L1) and 3rd and 4th (L3) lumbar vertebra and breast bone tissue thickness at 1st (BT1), 2nd (BT2), 3rd (S3) and 4th (BT4) sternebrae. Lambs were slaughtered after 24-h fasting and carcasses were cooled at 4 ºC for 24 hours. Carcass left side was dissected into muscle, subcutaneous fat, intermuscular fat and bone and remainder (major blood vessels, ligaments, tendons, and thick connective tissue sheets) associated with some muscles. Tissues measurements plus hot carcass weight were fitted as independent variables to predict carcass composition by stepwise regression analysis. Models developed 96.7% of muscle, 64.6% of subcutaneous fat, 95.0% of intermuscular fat, and 85.0% of bone weight variation, respectively. Ultrasound measurements were admitted in the models, improving the determination coefficient (R2) and reducing the residual standard deviation. The HCW and tissues measurements taken by ultrasounds in live kids can be used to develop models to predict carcass composition at slaughter-house level