Características da carcaça de cordeiros alimentados com dietas contendo diferentes níveis de fibra em detergente neutro

Abstract

The objective of this trial was to evaluate the effect of different dietary NDF levels on carcass characteristics of feedlot lambs slaughtered with 30 kg of body weight. Twenty crossbred Ile de France x Texel non-castrated male lambs were randomly assigned to the following treatments: 25%, 31%, 37%, and 43% of dietary NDF. The fo rage portion of the diet was composed by sorghum silage (hybrid AG 2005 E) and the concentrate by cracked corn, soybean meal, salt, limestone, and dicalcium phosphate. Diets were isonitrogenous averaging 17% of crude protein. The following variables were measured: hot carcass weight (HCW), cold carcass weight (CCW), hot carcass yield (HCY), cold carcass yield (CCY), cooling loss index (CLI), loin eye area (LEA), subcutaneous fat thickness (SFT), carcass length (CL), hind leg width (LW), chest depth (CP), hind leg length (LL), and weight and proportion of hind leg, shoulder clod, rib, and neck. Weight and proportion of hind leg bone, muscle, and fat also were measured in this trial. Increasing NDF from 25 to 43% in the diet linearly reduced HCW, CCW, HCY, CCY, and rib weight. A significant quadratic effect of dietary NDF level on LL was also found. No significant effects of the different dietary NDF levels were observed for the remaining variables. © 2006 Sociedade Brasileira de Zootecnia.