Desempenho, características de carcaça e qualidade da carne de ovinos alimentados com dietas contendo silagens de diferentes cultivares de sorgo

Abstract

This study aimed to evaluate the utilization of silage of assorted sorghum cultivars in feedlot lambs diets by means of apparent digestibility, nutrient intake, performance, carcass characteristics, non-carcass components and meat quality. Thirty five lambs, with average age between 5 and 7 months and average body weight of 17,7 ± 3,7 kg were used. The trial was conduct at the Experimental Station Pendencia, which belongs to the Empresa Estadual of Pesquisa Agropecuária – EMEPA, for 42 days. The lambs were randomly assigned to five treatments (Sorghum silage BRS 610, BRS 655, BRS 800, BRS 810 e Ponta Negra) with seven replicates. Data were submitted to analysis of variance and the mean values were compared by Tukey Test at 5% probability, proceeding to the Pearson correlation between the variables evaluated in the meat. The average intake of ether extract, neutral detergent fiber and non-fiber carbohydrates were affected by the treatments (P < 0,05). The intake of non-fiber carbohydrates when evaluated in metabolic weight showed significant differences, with the diet containing silage BRS 610 and Ponta Negra those who had lower intake. The performance, weight gain, feed conversion and feed efficiency were not affected by the experimental diets (P > 0,05). The silages propitiated similar intake and digestibility of nutrients. There was no significant difference on the carcass morphology, weight, hot and cold carcass weight, hot and cold carcass yield, biological yield, chilling losses, weight and yield of retail cuts and the subjective evaluation of carcasses. The fat thickness of the animals showed differences depending on the diets, with average value of 1,20 mm, and animals fed forage sorghum silage BRS 810 had lower fat thickness, although there was no difference observed in the composition of diets or weight gain that could justify this lower fat thickness. The slaughter weight, empty body weight, organs weight, gastrointestinal tract, byproducts and fat deposit were not influenced (P > 0,05) by the assorted sorghum cultivars. The average yield of the “buchada” and “panelada” was 3.78 and 21.54%, respectively. In order to evaluate the meat quality, physical-chemical analyses and centesimal composition were performed using the Longissimus dorsi muscle. The diets did not influence pH parameters (5,64), colour (L*23,13, a* 18,00, b* 15,78), cooking losses (34,43 %), humidity (72,53%), protein (24,08%), ash (1,09%) and lipids (2,99%). The shear force differed among the diets, with the silage of cultivar BRS 655 providing a tender meat (2,10 kgf/cm2). The finishing phase of undefined breed lambs in feedlots, based on diets containing silage of assorted sorghum cultivars such as grain, forage or dual purpose result in performance, intake, meat and carcasses with similar characteristics, thus, all tested silages can be used for sheep feeding.