Rate of gas production was increased by treating the straw with urea (a+b = 57.3 ml vs 39.8 ml for urea-treated and untreated straw). Adding molasses to the untreated straw increased the intake from 150 to 310 g DM/day. Adding molasses to the rice straw plus urea treatment increased the intake from 168 to 362 g DM/day but molasses addition had no effect on intake of the urea-treated straw (269 and 273 g DM/day. The sheep lost weight on untreated straw without (-11 g/day) or with molasses (-2 g/day). Best performance was with urea-treated rice straw plus molasses (37 g/day), which was better than urea-treated straw without molasses (15 g/day). Untreated straw with added urea and molasses supported a growth rate of 25 g/day. Feed conversion data were in the same order as the growth rates.
It can be concluded that urea-treatment plus supplementary molasses is the best way to offer rice straw to growing sheep.