Twelve adult Rahmany rams 62.4kg of body weight and 3 years of age were used in this study , with aimed to overcome oxalic acid in sugar beet  vein silage and to estimating the effects of oxalic acid residual on rumen microorganisms activities. The animals were randomly divided into four groups , assigned to four digestion trials. The experimental rations were50%concentrate feed mixture(CFM)+50% roughage as berseem hay  for control or one of sugar beet top silages either, untreated (USBS),chemical treated(CSBS) or biochemical(B-CSBS), for second , third and fourth rations respectively .Trials were conducted and lasted for 22 days .The results of  chemical composition for tested ingredients and calculated chemical composition of the consumed  rations fed by adult Rahmany rams reveals' that the B-CSBS was higher of CP and NFE, while the CF and Ash had lower values when compared with control and USBS groups, however the means of cell wall constituents of experimental diets indicated that the B-CSBS silage had the lowest contents of neutral detergent fiber (NDF),acid detergent fiber(ADF),acid detergent lignin(ADL),hemicelluloses and cellulose. on the other side ,the data of oxalic acid was clearly that the chemical and biochemical sugar beet  tops silages were lower of oxalic acid than those of untreated sugar beet tops .The digestibility of B-CSBS was higher in OM ,CP, EE and NFE compared with CSBS, USBS and control diet . At the same time the USBS was significantly higher (p<0.05) for NDF, ADF, ADL, cellulose and Hemicellulose than other tested groups. while feed intake of USBS was significantly (P<0.05)higher compared with other groups and the values were ranged between 2316-2952g / h /d dry matter. Ruminal TVFA were significant higher (p<0.05) of acetic, butrtate and iso-biotrate for USBS group compared with the other tested groups, whereas propionate and valerate were significantly lower (p<0.05) for the same treatments in this respect .The highest values of total celluolytic bacterial, total bacterial and total protozoal count were obtained at 3 hrs post feeding of USBS was significantly (P<0.05) lower. While the rumen nitrogen in both of chemical and biochemical treated sugar beet top silage caused increase of NPN in rumen, however, total nitrogen of B-CSBS was significantly(P<0.05)higher at 3 and 6 hrs post feeding compared with other experimental groups..