The present study was designed to investigate the effects of partial replacing green guar (Cyamopsis tetragonoloba) forage (GG) and rice straw or guar forage silage (GS) instead of concentrate feed mixture (CFM) on the digestibility, productive and economic performance and blood biochemical constituents of growing  lambs. Twenty four weaned of Farafra male lambs 5 months age and weighed in average 16.69 ± 2.65 kg, were used in a feeding trial for 120 days in a complete block design. Animals were divided according to their live body weight into three experimental groups (8 lambs each), Ration 1 (R1) consists of 60% CFM + 40 % rice straw (control), R2: (40% CFM + 40% GGF + 20 % rice straw and R3: (40% CFM + 40% GFS + 20% rice straw). GGF and GFS were used to cover a partial of protein from CFM. The experimental rations fed according to NRC (1985). Results indicate that the apparent digestibility coefficients of all nutrients and feeding value of rations containing (GG) or (GFS) were better (P<0.05) compared to the control ration. Percentage of apparent N-utilization was currently higher (P<0.05) for the guar green forage and guar forage silage (R2 and R3) rations than the control ration (R1). Significant increased (P<0.05) were reported on total feed intakes, total weight gains, average daily gains (ADG) and better feed conversion ratios (FCR) and economic efficiencies for groups R2 and R3 compared with control group. The realized ADG were 198.08 and 185.83 g/day for R2 and R3, respectively, while lambs of the control recorded 177.11 g/day. No significant differences among experimental diets in serum total protein, albumin, globulin, trans-aminase enzymes (AST and ALT), cholesterol, triiodothyronine (T3) and Thyroxin (T4) hormones. It could be concluded that, feeding guar green forage or guar forage silage up to 40% as partial replacement of concentrate feed mixture for Farafra growing lambs rations were recommended. Such rations resulted in superior nutrition, better daily gain, feed conversion and economic efficiency.