Effect of treating rice straw with urea on chemical composition and degradability using nylon bags method

The purpose of this study was to investigate the effects of treated rice straw with urea on chemical composition and degradability of dry matter, organic matter, neutral detergent fibre (NDFom) and acid detergent fibre (ADFom) using in situ technique. Experimental treatments were untreated rice straw (control) and rice straw treated with 1, 3 or 5% urea solution. Four rumen fistulated Kordish ram lambs were used for measurement of nutrients degradability measurement after 0, 4, 8, 16, 24, 48, 72 and 96 hours of rumen incubation. The results show that treating rice straw with urea reduced dry matter, NDFom and ADFom contents, while organic matter and crude protein concentrations and pH value were increased (P<0.05). However, treating rice straw with urea did not have any significant effects on lignin, acid detergent insoluble silica, neutral detergent insoluble silica and neutral detergent soluble silica concentrations (P>0.05). Although only 5% urea treatment could affect quickly degradable fraction ("a" fraction) of dry matter, but treating rice straw with either 3 or 5% urea solution significantly affected "a" fraction of organic matter, NDFom and ADFom (P<0.05). Treating rice straw with urea increased slowly degradable fraction ("b" fraction) and effective degradability of dry matter, organic matter, NDFom and ADFom (P<0.05). However, application of 1% urea solution had no effects on "b" fraction of dry matter and organic matter (P>0.05). The results of this study showed that treating rice straw with 3 or 5% urea solution effectively increased nutritive value and degradability of rice straw.