Theipresentistudyiwasiconductedito iinvestigate effect of feeding tree fodder iCassava iori Prosopis and itheiri mixturei withi ammoniatediwheatistrawionigrowthiperformance, blood metabolic and economic efficiencyiof growingiBarkiilambs. Twenty ionei growingi male ilambsiof Barki,iaged abouti3 months and weighed iniaverage 12.18±0.17 kg were divided irandomlyi intoithreeisimilarigroups. Each group housed separatelyiinishaded pen. Lambs received ration in groups. Lambs iwere ifed itested irationsiaccordingitoiNRC (1985) inutrientirequirementiforigrowingisheepiasifollow, concentrateifeedimixture (CFM) 40% +Roughage  60% (Cassava (C): treatediwheatistraw (TWS) at 50:50), G1; CFM (40%) + Roughage 60% (C: iProsopis (P): TWS at 37.5:37.5:25, respectively), G2. CFM (40%) + Roughage 60% (P: TWS at 50:50), G3. The feeding trailsilastedifor 18 weeks. Theicalculatediproximateichemicalianalysisiofiexperimental roughages showed that the OM%, CF% and EE% values were nearly similar in all experimental roughages. The highest CP% was recorded with C:P:TWS (18.01) followed by C:TWS (16.40) while the lowest value was detected with P:TWS (14.19). Moreover, theiNFE%iandiAsh%iwere the highest in P:TWS (38.97 and 14.19, respectively) followediby C:TWS (38.46 and 13.22, respectively) butithe lowestivaluesiwereirecorded with C:P:TWS (36.79 and 13.21, respectively). Methaneiproductionishowed negative correlationiwith phenolic compounds (TP, TT, and CT) andipositive correlationiwith fibericomponents. Tanninishowedidepressing effectiin fermentability of C:P:TWS and P:TWS. While, Cassava with treatediwheat straw (C:TWS) was the mostifermentable rationithaticouldibe associated to the low ADF and phenolic compounds. On the other hand, the combination of Cassava: Prosopis: treated wheat straw (C:P:TWS) was the least fermentable ration that could be due to the negative influence of high TT and phenolic compounds irrespective of ADL content. The highest value of final body weight (FBW) and total body gain (TBG) was recorded with G2 (34.69 and 22.39 kg, respectively) then G1 (34.17 and 21.97 kg, respectively) but, lowest values were detected with G3 (33.19 and 21.14 kg, respectively) and the differences were significant (P<0.05). However, there is no significant difference between G1 and G2 or G3 was observed for previous traits as well as in daily body gain (DBG). The best feed conversion (the lowest values) as kg DM intake/kg gain was recorded with G2 (3.58) followed by G1 (3.92) then G3 (10.40). The results indicated that most tested blood parameters (total protein (TP); albumin (A); cholesterol and triglycerides) were slightly highest with G2 followed by G1 then G3 without significant difference among dietary treatments. Moreover, the heights values of (A/G ratio, creatinine, AST, ALT, calcium and phosphorus) were recorded with G3 compared with other groups but without significant differences (P<0.05). The cost of consumed feed was slightly reduced with G2 (1.10 L.E/h) compared with G1 and G3 (1.15 and 1.13 L.E/h, respectively). But, the feed cost /kg gain was reduced with G2 (6.17 L.E.) while it was 6.61 and 6.73 for G1and G3, respectively. Thus, the economic efficiency was noticeably better with G2 (4.85%) followed by G1 (4.54 %) and lastly G3 (4.46 %). Iticouldibe concludedithat feed Cacaav or/and Prosopis treesialongiwith ammoniated wheatistraw couldn't have an adverse effect on blood metabolites, feed and economic efficiency and growth performance of growing Barki lambsiunderisemi-aridiarea