Fadel et al., 2004. Ciência Anim. Bras., 5 (1): 19-25

The voluntary intake and in vivo digestibility of ammoniated rice straw (with urea) and non-treated straw (NTS) were evaluated in adult male sheep weighing 35 to 38 kg of liveweight (LW). The sheep were allocated to the following treatments: T1=NTS + urea (20 g/kg of dry matter; DM), T2=NTS + urea (20 g/kg DM + concentrate), T3=treated straw (4% of urea with base in DM + 30% of water), T4=treated straw + concentrate. A completely randomized design with 4 replications was done. After the analysis of variance (ANOVA), the mean comparison was accomplished by the Tukey test (P<0.05). A significant difference was observed in DM digestibility. The rice straw ammoniation resulted in a significant difference (P<0.05) in the voluntary feed intake and protein (CP) consumption, the values being 61.04; 51.66; 8.82 and 5.23 g/kg LW0.75/day, respectively, for ammoniated rice straw and non-treated straw. The concentrate increased (P<0.05) the voluntary feed intake of DM and CP for both ammoniated and non-treated straw. Significant differences were observed (P<0.05) for DM apparent digestibility (62.12% and 55.16%) and neutral detergent fibre (69.78 and 60.93%), respectively, for ammoniated and non-treated straw. The concentrate offered increased (P<0.05) the DM and CP apparent digestibility for both ammoniated and non-treated straw. It was concluded that the highest nutritive value index of DM (60.95%) was obtained when the ammoniated straw with added concentrate was offered to sheep.