Abstract: One hundred lactating Holstein dairy cows were cows were assigned to investigate the effect of untreated Soybean Meal (SBM) by different treated SBM products; heat+ soy hulls addition (HS), extrusion treatment (EP), addition of tannin plant extract and essential oil (PA) or addition of tannin plant + pelleting (HPA) on rumen fermentation, milk production and composition of dairy cows from 17th-25th after calving. Basal experimental diet was formulated (containing untreated SBM) and used as control, SBM was replaced by four treated SBM products and fed to the five groups (20 cows per each). Solvent extracted untreated SBM exhibited greater effective degradability of CP and AA when compared with treated SBM products (HS, EP, PA or HPA). This was due to a greater fraction of soluble protein. Moreover, treated SBM products (HS, EP, PA and HPA) contained relatively low concentrations of lysine, arginine, histidine, alanine, praline, serine, aspartic acid and glutamic acid in different levels compared with SE product which suggesting binding and cross linking reactions involving these AA as a result of the treatment methods. Treated SBM feeding instead of untreated one had no effect (p>0.05) on dry matter intake while, improved milk production and milk-to-feed ratio across the whole experimental periods by about (2.2, 1.9, 3.2 and 4.4%) and by (2.5, 1.9, 3.8 and 4.4%) respectively. Moreover, treated SBM reduced (p<0.05) the concentrations of ruminal NH3-N by about 8.5, 7.8, 13.2 and 13.2% respectively, while had no effect (p>0.05) on total VFA, acetate, butyrate concentrations and slightly decreased propionate in the rumen when compared with cows fed on untreated SBM containing diet. Regarding blood serum units treated SBM had no effect (p>0.05) on blood serum glucose concentration, however cows fed on diets containing EP, PA and HPA treated SBM instead of untreated SBM showed a reduction (p<0.05) in blood urea N by about 4.9, 6 and 7.7% respectively, on the other hand HS treated SBM leading to non significant (p>0.05) reduction in blood urea N by about 3.8%. Treated SBM products increased milk fat percentage, fat yield and protein yield and had no effect on milk lactose percentage and the present study suggested that HS and EP treatment methods of SBM is less effective and the cow performance lesser respond than PA or HPA methods which depend on tanninferous plant species that protect protein from degradation in the rumen due to presence of small amounts of condensed tannin in the plant species and may be more available and digestible in the intestine more than the previous processing.