Prediction of carcass tissue composition of F1 crossbred goats finished on native pasture Predição da composição tecidual da carcaça de caprinos mestiços F1 terminados em pastagem nativa

The objective of this study was to estimate tissue composition of the carcass from physical composition of commercial cuts of F1 crossbred goats (Boer with females of non-defined racial standard) finished on native pasture with four levels of supplementation with concentrate (0.0; 0.5; 1.0 and 1.5% of BW in dry matter). It was used 24 non-castrated animals at initial body weight of 15.52 kg and at 120 days of age. The carcass was sectioned in the half, and from the lefthalf carcass, the following cuts were detached: leg, loin, ribs, shoulder and neck, which were dissected in muscle, bone and fat. Carcass weight and yield were predicted from the weight and yield of tissues in the commercial cuts by regression analysis. All the cuts can be used to predict muscle and fat weight in the carcass. For the muscle, the relationship was linear and positive in the cuts leg, ribs, shoulder and neck, and cubic in the loin; for all the cuts, fat kept a linear relationship with the carcass. Muscle and fat yield of all the commercial cuts showed a positive linear relationship with carcass yield, except for rib fat, for which a cubic relationship was found. Considering all the results obtained and using the relationship with the highest determination coefficient, the ribs were the cut that provided the best estimate of the carcass muscle and fat yields of F1 crossbred goats (Boer with females of non-defined racial standard) finished on native pasture.Objetivou-se estimar a composição tecidual da carcaça a partir da composição física dos cortes comerciais de caprinos mestiços F1 (Boer com fêmeas de padrão racial não definido) terminados em pastagem nativa com quatro níveis de suplementação com concentrado (0,0; 0,5; 1,0 e 1,5% do PC em matéria seca). Utilizaram-se 24 animais não-castrados com peso corporal inicial de 15,52 kg e 120 dias de idade. A carcaça foi seccionada ao meio, e da meia-carcaça esquerda foram separados os cortes: perna, lombo, costilhar, paleta e pescoço, os quais foram dissecados em músculo, osso e gordura. O peso e rendimento da carcaça foram preditos a partir do peso e o rendimento dos tecidos nos cortes comerciais, por meio de análise de regressão. Todos os cortes podem ser utilizados para predizer os pesos de músculo e de gordura na carcaça. Para músculo, a relação foi linear e positiva nos cortes perna, costilhar, paleta e pescoço e cúbica no lombo; para todos os cortes, a gordura manteve relação linear com a carcaça. O rendimento de músculo e de g