The aim of the present investigation was carried out to study the effect of inclusion dried yeast culture and monensin sodium as dietary natural additives to manipulate of nutrient utilization, some rumen fermentation, blood constituents' parameter and animal performance in twenty one neonatal male buffalo calves (Bubalus bubalis) with average body weight (LBW) of 42.4±3.15 kg and one week of age were randomly assigned to one of three treatments (7 calves/each) in designed treatments consisted of basal diet fed milk as 10 % of body weight (control); 2nd group (YG) fed basal diet plus 10gm of yeast culture (strain 1026) and 3rd group (MG) fed basal diet plus 1mg of monensin sodium/kg BW/day for 105 days of
age as experimental period.Results showed neonatal calves fed YG group were higher (P<0.05) in digestibility of DM, CP, CF, TDN%, DCP% and total VFA concentration. In contrast, ruminal pH value was lower at 3hr after feeding as compared with other treatments. Nevertheless, rumen ammonia nitrogen concentration, propionate% and acetate to propionate showed a significantly increased (P<0.05) in MG group while, acetate% remained unaffected among treatments.On the contrary, butyrate% was significantly decreased (P<0.05) with YG and MG treatments compared to the control group. Plasma total protein and globulin were highly significant in YG and MG. However, AST and ALT activity decreased.No statistical significancedifferencesbetweentreatmentsinplasmaalbumin,A/Gratio,creatinine concentration, urea-nitrogen and immunoglobulins (IgG). While, daily weights gain, dry matter intake and feed conversion tended to be better in YG than the other groups. In conclusion, previous findings suggested a potential for yeast culture affect could be more widely safely accepted and effectively replace of monsion as growth promoters supplementation in pre-weaning buffalo calves rations.