This study was conducted to evaluate the effects of electron beam irradiation of soybean meal and canola meal on ruminal, post ruminal and total tract digestibility's of dry matter and crude protein and to compare responses of performance and physiological lactating dairy cows. In ihy;-situ Trail, four ruminally fistulated and one T-shaped cannulated non-lactating Holstein cows were used for in situ and mobile nylon bag techniques. Samples were incubated with rumen for 0, 2, 4, 8, 12, 24 and 48 h, then dry matter and crude protein degradation were estimated data to fitting disappearance by nonlinear equation. Untreated and treated proteins bag residues were fractionated by gel electrophoresis and densitometrical scanning. There was no difference (P 0.05) for degradation characteristics and effective rumen degradability values of crude protein between untreated and electron beam irradiated feedstuffs. Beam electron irradiation increased canola meal post-ruminal crud protein digestibility. SDS-PAGE indicated that in untreated soybean meal the ?-subunit of conglycinin and two subunits of glycinin and irradiated soybean meal ?-subunit of conglycinin and two subunits of glycinin; in untreated canola meal four subunits cruciferin and a subunits of napin and irradiated canola meal four subunits cruciferin and a subunits of napin make appreciable contribution to metabolizable protein when are fed to ruminants. In in-vivo Trail to evaluate effect of electron beam irradiation of soy bean meal and canola meal on performance and physiology of Holstein lactating cows, In experiment with treatments containing soy bean meal and canola meal, nine lactating Holstein cows at 84±17 days in milk were used to investigate production yield and total tract digestibility of soybean meal and canola meal. This trail was in at 3×3 Latin square with three replicates with 21 days periods. Cows were fed with three ratio control treatment without any irradiation in meals, soybean meal treatment with irradiated soybean meal and canola meal treatment with irradiated canola meal. Rations were consist of concentration and hay in ratio 59:41. Dry matter intake in all rations were not different (P 0.05). A significant reduction was observed in irradiated treatments rather than control treatment in regards of dry matter organic matter, and neutral detergent ?ber How're there was no significant different between two irradiation treatment including soybean meal and canola meal rations. Canola meal treatment cause to significant reduction in acid detergent ?ber rather than control treatment while crude protein was Key Word Degradation, soybean meal, canola meal, SDS-PAGE, Mobile Nylon Bag, Electron Beam Irradiation,