Eighteen cross-bred (Tharparkar x Brownswiss) calves (8-12 m; 90-150 kg) randomly divided into three equal groups were fed on untreated (A)) 4% urea + 44% moisture ereated (B) and 5% urea + 30% moisture treated (C) rice straw as basal roughage for 120 d. Concentrate mixture was fed to all the animals as per their requirements. The mean live weight gain (g/d) was 416.67 ± 14.67, 562.50±26.42 and 541.67±20.53 under A, B and C respectively. The apparent digestibilities of DM, CF, NDF, ADF and cellulose were siggificantly (P<0.01) higher in B and C as compared to A but the digestibility of CP was not affected. The average N intakes (g/d) in A, B and C were 91.89±2.68 ; 96.67±1.84 and 112.68±4.11respectively,with corresponding N balances (g/d)of 22.66±0.99; 28.10±0.71and 27.74±0.65. DCP (g/d); TDN (kg/d) and ME (Kcal/d) intake increased significantly (P<0.001) in ammoniated rice straw fed groups.
