The performance of steers fed diets using asroughage rice straw treated with anydrous ammonia, rice straw+urea, sugar cane+ urea and sorghum silage were evaluated. Sixteen PO Simental steers, averaging400 kg initial LW, were assigned to a completely randomized design. The experimentlast 88 days, 15 days of adaptation and 61 experimental days, divided in threeperiods of 21 days. Total DM intake, that ranged from 7.1 to 10.0 kg/day, differamong treatments, where higher intakes were observed for the animals fed ammoniatedrice straw and sorghum silage, that did not differ. Feed:gain ratio did notdiffer among different diets, and an average value of 6.6 was recorded. It wasobserved higherweight gain for the animals fed ammoniated rice straw (1.59 kg/day)in relation to the animals fed straw+urea (1.25 kg/day). The treatement withanydrous ammonia improved the rice straw nutritive value resulted in highervoluntary intake of this roughage and, consequently, in higher daily weightgain in relation to no treated rice straw and supplemented with urea.
