Diferentes proporções de concentrado em associação ou não com gordura protegida em dietas para cordeiros.

Abstract

This study was carried out to evaluate the effect of the inclusion of different concentrate levels in diets with or without the inclusion of protected fat on intake, nutrient digestibility, productive performance, microbial protein synthesis, and feeding behavior in feedlot lambs. Sixty-four non-castrated Santa Inês male lambs at an average body weight of 20.07 ± 0.25 kg and an average age of four months were used. The animals were distributed in a completely randomized block design (CRBD) in a 4 x 2 factorial arrangement, represented by 4 concentrate-to-roughage ratios (C:R ratio; 40:60; 50:50; 60:40 and 70:30) and 2 levels of protected fat inclusion (BeefFat; 0 or 35 g/Kg, on dry matter basis). The animals were randomly assigned to the experimental diets regarding the C:V ratio with or without protected fat. There was and interaction between the inclusion of concentrate and protected fat for digestibility coefficients of crude protein (P<0.0001) and ether extract (P = 0.0443), final weight (P = 0.0425), average daily gain (P = 0.0204), total weight gain (P = 0.0204); and uric acid concentration (mmol/day) (P = 0.0409). In general, the inclusion of up to 700 g/kg and 35 g/kg of protected fat reduces intake and changes nutrient digestibility in feedlot lambs. The inclusion of 700g/kg of concentrate without the use of protected fat is recommended to promote better productive performances, reduce rumination activity and increase the feeding efficiency of dry matter in feedlot lambs.