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The present study was conducted to determine some feedstuffs nutritive values through different methods and to make a comparison between the methods. Six canulated steers (Holstein and Sistani) were taken into experiment in a completely randomized design of two observations per each replication. The amount of gas production at 0 , 2 , 4 , 6 , 8 , 12 , 24 , 48 , 72 and 96 hours and feed degradation through nylon bag method at 0 , 4 , 8 , 16 , 24 , 48 , 72 and 96 hours were measured . The feedstuffs used included: alfalfa hay , wheat straw , corn silage , concentrate and cotton seed, fed at the maintenance level. Dry matter degradability at 96 hours for alfalfa hay , wheat straw and corn silage were 71.52 , 51.02 and 77.89, and at 48 hours for concentrate and cotton seed were 80.59, and 53.51 percent, respectively. Dry matter effective degradability for the above feedstuffs at the maintenance level were 64.40, 36.70 , 66.43 , 76.03 and 48.16%, respectively. Dry matter degradability for these respective feedstuffs at 24 hours were 66.93 , 33.57 , 68.24 , 79.83 and 48.71. The amount of gas production at 96 hour of incubation for alfalfa hay , wheat straw and corn silage were 51 , 45 and 75.5 milliliters , respectively , and for concentrate and cotton seed at 48 hour of incubation were 81 and 58.5 milliliters. Correlation coefficient between dry matter degradation and gas production for these feedstuffs were 0.99, 0.99 , 0.99 , 0.96 and 0.99 respectively and correlation coefficient between crude protein degradation and the amount of gas production were respectively recorded as 0.97 , 0.99 , 0.99, 0.99 and 0.98. Due to the high correlation coefficient existing between dry matter degradation, crude protein degradation, ADF and NDF degradation, and gas production, regression equations between these parameters and gas production were assessed for an estimationof the amount of these parameters from the amount of gas production without a need for tedious digestion experiments. As an example regression equation between alfalfa dry matter degradation and its gas production was: Y = 35.724 + 0.714x. In line with 51 milliters of gas production for alfalfa at 96 hour, this equation estimated 72.14% of degradation for alfalfa dry matter during this time, which in comparison with the 71.52% from digestion experiments, there is not any significant difference observed between the two recordings .