Weight gain and carcass characteristics of lambs receiving different levels of energy in the ration

Abstract

This work was conducted with the objective of evaluating the influence of different levels of energy in the ration on the performance and carcass characteristics of sheep, finished in feedlot and slaughtered with 32 kg of live weight. Three treatments were evaluated: 2.23, 2.54 and 2.85 Mcal of ME/kg of DM, being the last treatment the recommendation of the National Research Council - NRC (1985) for weight daily gains of 250 g in lambs. Eighteen, intact, Texel crossbred lambs were used; six per treatment. Lambs were fed with isoprotein rations (16.70% CP). The energy recommendations proposed by the NRC (1985) resulted in smaller weight gains than expected. The energy level had a linear effect (P < 0.05) on weight gain (?=-190+141X). Diets with greater energy supply rendered greater weight gains, and consequently less time for the termination of the lambs. Carcasses of animals slaughtered with similar weights presented different morphological characteristics.