Abstract
Twelve male crossbred calves of 18 months of age were divided into two groups of six each. Animals in both the groups were fed wheat straw ad lib. However, animals in group II had free access to urea molasses mineral block (UMMB) lick. Straw DM intake (kg/100 kg B. Wt. and $g/w^{0.75}\;kg$) was significantly (p < 0.01) higher in group II ($1.95{\pm}0.06$; $75.55{\pm}1.79$) as compared to group I ($1.27{\pm}0.08$; $48.77{\pm}2.43$). Straw DM digestibility coefficient was not significantly different in groups I and II. However, DOMI (kg/100 kg B. Wt.) was significantly (p < 0.01) higher in group II ($0.986{\pm}0.05$) as compared to group I ($0.615{\pm}0.03$). Digestibility coefficient of DM, OM and CP were significantly higher in group II as compared to group I. However, digestibility coefficients of EE, CF and NFE were non-significantly different between the two groups. Animals in group II exhibited significantly (p < 0.01) higher and positive N, Ca and P balances as compared to group I which exhibited negative balances. Total-N, ammonia-N and urea-N in the blood plasma of animals in group II were significantly (p < 0.01) higher as compared to group I.