Desempenho, características de carcaça e avaliação econômica da substituição do milho grão inteiro por casca de soja peletizada na alimentação de cordeiros em confinamento 1 Performance, carcass traits and economic evaluation of the replacement of corn whole grain by pelleted soybean hulls in the feeding of feedlot lambs

This work was carried out with the objective of evaluating the effects of different levels of replacement of whole grain corn by pelleted soybean hulls in high concentrated diet, without long fiber use, on intake, productive performance and economical viability of feedlot lambs production. Twenty four Texel lambs, 12 males and 12 females of the same age, with average weight of 23 kg, distributed in 12 stalls, in a completely randomized design, were used. The treatments consisted of replacement of whole grain corn by pelleted soybean hulls, at levels of 0% (SH0), 15% (SH15) and 30% (SH30). Dry matter (DM) (kg day-1), crude protein (CP) (kg day-1, %AW, g AW0,75), and neutral detergent fiber (NDF) (kg day-1, %AW, g AW0,75) intake showed linear increasing behavior (P<0.05) according to increasing levels of soybean hulls replacing the corn grain in the diet, however, the ether extract (EE) intake (g day-1) presented quadratic effect. There were no differences in DM intake in relation to weight and metabolic body size, as well as, to mineral material (MM) (g day-1) and total digestible nutrients (TDN) intake (kg day-1, %AW, g AW0,75). In average daily gain (ADG), a quadratic effect of different levels of soybean hulls in the diet was observed (P<0.05), with weight gain of 0.267; 0.327 and 0.224 kg day-1, in levels of 0, 15 and 30%, respectively. The feed conversion was affected in a increasing linear way (P<0.05) with the soybean hulls inclusion in the diet. It was not observed differences in the carcass traits. When increasing levels of soybean hulls were added to the diet, it was observed decreasing in cost/kg ration (R$), however, there was increasing cost of meat produced (kg). In a general way, it can be concluded that replacement of whole corn by pelleted soybean hulls in high concentrated diet, in a proportion of 15%, increases the weight gain in feedlot lambs. In the proportion of 30%, affect negatively the animal performance, however does not influence the carcass traits. Diets without soybean hulls produce meat (kg) at lower cost.