Salmonellaenterica serovar typhimurium (S. typhimurium) was isolated from both dead and clinically diarrhoeic beef calves, which had history of severe diarrhoea. Another two serovars ((Salmonella enterica serovar dublin (S.dublin) and Salmonellaenterica serovar muenster (S.muenster)) were demonstrated from both clinically diarrhoeic calves as well as from the contact apparently healthy ones. Out of 77 diarrhoeic cattle calves, 34 were proven positive for Salmonella isolates (44.2%) whereas the apparently healthy contact calves showed lower rate of isolation 12 out of 97 (12.9%). S.typhimurium was the most dominant serovar as revealed from the isolation pattern. In clinical diarrhoeic cases S. typhimurium constituted 21 out of 34 isolates (61.8%) and 9 out of 12 (75%) in apparently healthy calves. Salmonelladublin and muenster were isolated in lower patterns, as 11 out of 34 isolates (32.3%) and 2 out of 12 (16.7%) in case of S.dublin whereas 2 out of 34 (5.9%) and 1 out 12 (8.3%) in case of S.muenster were detected in diarrhoeic and apparently healthy calves respectively. Lipopolysaccarid (LPS) ElISA demonstrated higher antibodies titer in the diarrhoeic animals (1:2400 to 1:9600) than apparently healthy calves (1:400 to 1:7200). After administration of Lactobacillus casei (L.casei) (10¹⁰cfu) to clinical diarrhoeic calves, the diarrhoea stopped and the shedding of Salmonella ceased. Coliform counts were also reduced with remarkable increase in the Lactobacillus counts were determined (6.47+2.2log₁₀). The humoral as well as the cellular immune responses were also boosted. Salmonella antibodies levels were significantly increased and inhancement of the macrophages activity was demonstrated (from 4.4+1.2 to 33.2+5.1 cell. macrophage). Serum biochemical analysis of diarrhoeic calves showed significant decrease in total proteins, albumin, globulins, A/G ratio as well as glucose levels. The enzyme activity of ALT, AST, alkaline phosphates as well as the values of creatinine, urea and uric acid were significantly increased. Serum minerals profiles were also altered where calcium, phosphorus, magnesium, zinc, cupper, iron, sodium and chloride were decreased, whereas potassium was significantly increased. After treatment with L. casei significant improvements of certain biochemical parameters were observed.