Desempenho e qualidade de carcaça de garrotes Nelore e F1 Rubia Galega x Nelore suplementados com Cromo Picolinato

Abstract

The effect of protein energy supplementation with chromium picolinate (CrP) on productive performance and carcass characteristics was studied in sixty young male bovine of two genetic groups (30 NEL = Nellore and 30 NRG = F1 Rubia Gallega x Nellore). After weaning (at 210 days of age), the animals were kept in 2 paddocks, separated according to supplementation (with and without CrP), containing the 2 genetic groups (15 NEL and 15 NRG). The experiment lasted 320 days divided into 2 phases: growing phase (210 to 420 days of age), and termination phase (421 to 530 days of age). In the growing phase the animals were supplemented in the proportion of 0.2% of body weight / day (1.0 mg CRP / kg supplement), while in the finishing phase 0.5% of body weight / day (0.5 mg PCr / kg supplement). There was no interaction effect (P> 0.05) between genetic group and CrP supplementation on performance and carcass characteristics in both phases. In the growing phase NRG animals showed values above the NEL (P <0.001) growth performance. However, in the finishing phase, the performance was similar (P> 0.05) among genetic groups. During the growing phase supplementation with CrP increased (P = 0.025) ADG, metabolic ADG (P = 0.026), total weight gain (TWG, P = 0.025) final percentage of GPT (P = 0.031), body weight (PCF, P = 0.025) and metabolic PCF (P = 0.026). However, supplementation with CrP reduced (P <0.005) ADG in the finishing phase, as well as the metabolic ADG (P = 0.004), GPT (P <0.005), percentage of GPT (P = 0.005) and body weight slaughter (PCA, P <0.005). The genetic group and the dose of CrP did not affect (P> 0.05) rib eye area (REA), fat thickness (SFT), hot carcass weight (HCW), carcass yield (HCY), conformation and the carcasses. The NRG have better performance and higher rate of growth of muscle and bone tissue that NEL, but are similar in fat deposition. CrP supplementation does not influence carcass quality and accelerates body growth in the growing phase. However, taking into account the productive performance, is disadvantageous keep CrP supplementation in the finishing phase.