Medidas ultrassonográficas para predição da carcaça de cordeiros leves e pesados ao abate

Abstract

The aim of this study was to verify the correlations and develop prediction models based on ultrasound measurements to estimate the tissue composition of lamb carcass. Thirty-six lambs from the Pantanal genetic group, weaned with an average body weight of 12.78 kg ± 2.03 kg, were used. The animals were randomly distributed in four treatments, with nine replicates per group. The lambs were finished in a feedlot, with an experimental diet formulated for a daily weight gain of 300 g and available water ad libitum. When they reached the established weight, ultrasound images were taken between 12th and 13th ribs to obtain the Musculus Longissimus depth (PML) and subcutaneous fat thickness (EGS). Gluteus depth (PP8) and subcutaneous fat thickness in the rump (EGP8) were determined. At dissection total fat (subcutaneous + intermuscular fat), muscle, bone, and others were separated to determine the fat proportion of muscle, bone, and fat. For the statistical analyses of the half carcass, were calculated the percentage and the total amount of fat, muscle, bone, also muscle/fat and muscle/bone ratio. The collected data were analyzed between the in vivo measurements obtained by ultrasound (independent variables), and the tissue composition of the carcass (dependent variable). For statistical analysis, the animals were divided into two groups, light (20 to 25 kg) and heavy (30 to 35 kg). The (EGP8) had more relevance in the models for predicting tissue composition for light animals, while (EGS) had more relevance in heavy animal models, becoming an indicative measure of carcass finishing. Thus, the animals of the light group present better tissue composition.