Avaliação dos indicadores indigestíveis na estimativa de produção fecal e digestibilidade em ovinos e caprinos

Abstract

The objective of this study was to compare the indirect methods of obtaining digestibility with the direct method of total fecal collection to estimate the apparent digestibility of nutrients in sheep and goats supplemented with non - protein nitrogen. Five goats and five sheep without defined racial pattern (SPRD) were used, distributed in two 5 x 5 Latin squares, with subdivided plots, considering as plots the diets and as subplots the methodologies of determination of apparent digestibility. The diets were composed of buffelgrass hay and the addition, via ruminal infusion, of increasing amounts of nitrogen supplementation in order to gradually raise the CP level of the basal diet in intervals of two percentage points, that is, +2, +4, +6 and +8%. Samples of the foods offered and the leftovers were collected daily during the five days of collection to determine the nutrient intake, as well as the total collection of faeces to determine the apparent digestibility of the nutrients. The amount of fecal dry matter excreted was estimated by the concentration of Fiber in Indigestible Acid Detergent (FDAi), Indigestible Neutral Detergent Fiber (FDNi), Indigestible Dry Matter at 244 hours (MSi 244H) and Indigestible Dry Matter at 264 hours (MS 264H ). The statistical analysis of the variables was performed by orthogonal contrast to compare the indirect methods of determination of apparent digestibility of nutrients (FDAi and FDNi) with the direct method of determination of apparent digestibility (total collection of feces) of the nutrients in the different diets. The level of 5% of significance was adopted. Among the indicators evaluated, the indigestible neutral detergent fiber (NDFI) is the one that most accurately estimates the nutrient digestibility of the diet for goats and sheep.