Silva et al., 2002. Rev. Bras. Zootec., 31 (3): 1258-1268
Digestao total e parcial de alguns componentes de dietas contendo diferentes niveis de casca de soja e fontes de nitrogenio, em bovinos
This experiment was conducted to evaluate the effect of two levels of soyabean hulls and three sources of protein on the total and partial rumen and intestinal digestion. Six Holstein-Zebu steers averaging twelve months of age and 229 kg BW were fistulated in the rumen and in the abomasum and distributed in a 6*6 Latin square and fed ad libitum individually. The consumption and the total and partial digestibility of the nutrients were evaluated. There was no effect of the source of protein on consumption, amounts of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fibre (NDF) and acid detergent fibre (ADF) in the rumen, abomasum and in the faeces and on the digestibility coefficients of these components. On the other hand, increasing the levels of soyabean hulls significantly increased the coefficients of digestibility in the whole digestive tract. However, the levels of soyabean hulls did not affect the digestion of CP, NDF and ADF in the intestines. The results indicate that soyabean hulls can replace maize, due their degradation similarity, and can partially replace the roughage in rations for ruminants, by having high levels of fibre with great potential and speed of ruminal fermentation. Poultry by-product meal and starea can replace soyabean meal without negative effects on the digestion of their nutritive components.