Department of Animal Science, Govind Ballabh Pant University of Agriculture and Technology, Pantnagar-263 145, India
Online published on 20 January, 2012.
Ammonia (urea) treated rice straw (ATS) fed with three protein supplements namely cotton seed cake (CSC), leucaena leaf meal and fish meal to supply 30 per cent of the theoretical needs of protein for normal growth in crossbred heifers was compared with unsupplemented ATS, untreated straw supplemented with urea or concentrates to balance the DCP and TDN requirements, using five heifers per diet. The digestibility of DM among diets did not differ significantly (P > 0.05). The fibre digestibility on ATS diets was, however, significantly (P < 0.05) higher than that on untreated straw diets. The intake of DM and DDM on ATS diets were also significantly (P < 0.05) higher than those on untreated straw diets. The differences in balances of N and Ca amongst diets were non-significant, while the P balance on untreated straw-concentrate diet and ATS either alone or supplemented with fish meal, or CSC were similar but these were significantly (P < 0.05) higher than those on untreated straw enriched with urea or ATS supplemented with leucaena leaf meal diet. ATS diets supported faster and cheaper live-weight gains than untreated straw except when large amounts of concentrates (1 8 kg/d) were given. The importance of giving small amounts of protein supplements (500 g/d) which escape the rumen fermentation with ATS is stressed.
