Processamento físico do milho e gordura protegida em suplementos múltiplos para bovinos de corte em terminação a pasto

Abstract

The objective of this study was to evaluate the supply of protected fat and maize grain processing in multiple supplements for cattle in the dry season on dry matter intake, nutrient digestibility, carcass characteristics and productive performance. Two experiments were conducted to evaluate the use of protected palm fat and protected soybean fat, as well as providing maize in different physical forms. In the first experiment, five non-castrated Nellore bulls with initial weight of 645.8 ± 34 kg, distributed in 5x5 Latin square, were used for the tests of consumption and digestibility. The supplements were compared with fine corn (MF), crushed in a sieve of 0.8 mm, medium fine corn (MMF) ground in a 3 mm sieve, coarse corn (MMG) ground in a 10 mm sieve, coarse corn (MG) crushed without sieve and whole corn (MI). The supplements did not change the dry matter intake (P> 0.05), the finely processed grains had higher intestinal digestibility and total starch digestibility (P <0.01). The second experiment evaluated the addition of protected fat soybean and palm fat) during the pasture termination phase, the performance, carcass characteristics, nutrient intake and digestibility were evaluated. The study was developed in a completely randomized design with 48 steers (initial weight 389.5 ± 20 kg and initial age of 16 months), Nellore, male and uncastrated, randomly distributed in 16 pickets (3 animals / picket). The treatments were: control (CO, fat free supplement); palm fat (PF, control supplement with protected palm fat); soybean fat (SF, control supplement with protected soybean fat) and protected fat association (PSF). Reductions in crude protein intake (P <0.05) and increase in intake of ethereal extract (P <0.05) were observed when fat was added to the supplement. Supplementation with soybean fat reduced the average daily gain in relation to soybean fat (P <0.05). However, there was no difference in carcass gain (P> 0.05), regardless of fat source. The protected fat is a tool to increase the finishing of pre-grazed cattle finished in pasture in the dry season.