Níveis crescentes de gordura protegida na terminação de cordeiros em confinamento

Abstract

The objective of the experiment was to evaluate the increasing levels of protected fat in diets high concentrate on performance, carcass traits and costs of finishing phase of feedlot Suffolk crossbred lambs. Were used 18 male lambs, intact, with 18.8 kg of inicial weight and mean age of 70 days. The animals were confined for 63 days, after 14 days of adaptation to installations and experimental diets. Were evaluated four diets, a control diet (without protected fat) and diets containing 4.2% and 5.8% of protected fat. The commercial product used as a source of protected fat was Megalac ®, all diets were isoproteic and contained unique hay as forage. Were evaluated the animal performance, carcass traits, non-carcass components, as well as the cost of each treatment. The experimental design was randomized and the means compared by Tukey test, at 5% of significance. The body weight gain was, on average, 39.4% higher in the treatments 0% (0.274 g/day) and 4.2% (0.292 g/day) when compared to 5.8% treatment (0.203 g/day). The dry matter intake showed similar results as weight gain. It was observed, in respect to carcass characteristics, that the 5.8% treatment presented lower results when compared to 4.2% treatment for the characteristics of pre-slaughter weight, hot and cold carcass weight. The lambs that received additions of 4.2% of protected fat in the diet had higher carcass weights, explained by an earlier development. As for allometry, the carcass growth, on average, was considered late, while the head was early. The inclusion of fat interferes in the proportion of body and regional components. The difference in weight gain and final carcass weight is not enough to offset the increased cost with the inclusion of protected fat in the diet of confined lambs.