The experiment was conducted to evaluate the effects of urea addition and two storage periods on the nutritive value and fermentation profile of sorghum silage. A randomized complete design was used, in a 4 × 2 factorial arrangement, with urea doses (0; 2.5; 5.0 and 7.5% in DM) and two storage periods (30 and 60 days). The PVC silos, 50 cm high and 10 cm in diameter, were used to ensilage the sorghum. Urea doses had a quadratic effect on the DM content and positive linear effect on CP, NDIP and IVDMD, but storage periods had no effect on these variables, except on NDIP with greatest value was obtained at 60 days storage. Urea doses had a negative linear effect on NDF, ADF, cellulose and lignin. The values for NDF, ADF, cellulose and lignin there were greater at 60 days of storage than at 30 days. The fermentation profile analysis showed that there was urea doses × storage period interaction on pH only. Urea doses had quadratic effect on ammonial nitrogen (N-NH3) and positive linear effect on pH value. The greatest values for N-NH3 were observed at 60 days of storage as for pH in the zero urea dose. Adding urea addition to sorghum ensilage can increase the nutritive value of the silage without damaging theui fermentation profile.
ammoniation; fermentation profile; nutritive value; roughage
