Nutrient intake, apparent digestibility and total digestible nutrients (TDN) levels of sugar cane, elephant grass silage, corn silage and sorghum silage were evaluated in sheep. The TDN values of feeds were also estimated with the equations proposed by NRC (2001). Twenty male castrated rams, housed in individual pens, were distributed in a randomized design in four treatments (feedstuffs) and five repetitions (animals). Nutrient apparent digestibility was determined by using total collection of feces. To compare predicted TDN values with in vivo TDN values, data were adjusted to a linear regression model. Sheep fed with the silages consumed larger amounts (P < 0.05) of nutrients than those fed with sugar cane. There was not difference (P > 0.05) for TDN intake among silages. The apparent digestibility of the dry matter (DM), organic matter (OM), crude protein (CP), ethereal extract (EE) and neutral detergent fiber (NDF) did not differ (P > 0.05) among treatments. There was difference (P < 0.05) between predicted and in vivo values of TDN. The equations proposed by NRC (2001) were not suitable to predict energetic value of tropical forages.
Silage; sheep; neutral detergent fiber; nutritive value; total digestible nutrients