Three healthy Rahmany rams were used. They were fed at 90% of their ad libitum intake during successive metabolism trials. The experimental rations were formulated to be almost iso-nitrogenous and contain about 12% crude protein recommended by rskov et al. (1972) to ensure maximal rate of fermentation in the rumen as follows: 1.30% rice straw (RS) + 70 % concentrate feed mixture (CFM) 2.30% maize stalks (MS) + 70 % CFM 3.40% clover straw (CS) + 60 % CFM 4.60 % RS + 30% CFM + 10% SBM 5.