Abstract: This experiment was done to evaluate the potential use of steam treated bagasse pith (SPB) in feeding of Lori Ewes. Forty eight ewes with similar condition from many flocks of autumn of Lori sheep were included in this experiment. The ewes divide into 4 groups of 12 sheep. The ewes allocated into 4 different levels of SPB (0, 5, 10 and 15%) for pre and post lambing in a completely randomized design. The diets were formulated according to NRC (1994) and had similar quality for protein, energy and high concentration of other nutrient. Concentrates were included amounts of 0, 10, 20 and 30 percent of SPB witch replaced with wheat bran and barely. Ewes live weight were measured before and at lambing and 2 weeks interval after that until weaning lamb. Milk sampling for determination of fat, Protein, carbohydrate and Solid Not Fat (SNF). Blood collected via jugular vein to indicate baseline (blood urea nitrogen, triglyceride, cholesterol and glucose). Statistical analysis with SAS program (1994) was indicated that, there were not significant differences between diets for milk composition percentage (fat, Protein, carbohydrate and solid not fat) (p<0.05). The effect of different levels of SPB on body change weight ewes and Average Daily Gain (ADG) lambs not significantly (p<0.05) different. Also there were not significant differences between diets for plasma cholesterol, BUN, triglyceride and glucose (p<0.05). In conclusion result of that could be SPB substituted instead of 30% concentrates (15% of whole diet) with no negative effects on physiological and productivity in pre and post lambing.