A total of 148 faecal samples (80 from apparently healthy and 68 from diarrheic calves), air (45), water (30), soil (31), dam coat (148) and teat and subjected for a dairy farm swabs (148) were collected from
bacteriological examination. The obtained results revealed that E. coli and Salmonella serotypes could be isolated from apparently healthy (70 and 3.7%) and diarrheic calves (79.4 and 10.3%). In addition, E. coli and Salmonellae were recovered from air (13.3 and 4.4%), water (70 and 6.6%), soil (71 and 25.8), dam coat (50.7 and 10.1%) and teat swabs (26.3 and 4.7%). Moreover, serotyping of isolated Salmonellae from calves and environment was carried out. Also, other Gram-negative and Gram-positive bacteria isolated from calves and environment were recorded. On the other hand, it was found that TH4+ is effective against E. coli (at concentrations of 0.5 and 1% after contact period of 20 minutes and 10 minutes respectively) and Sal typhimurium (at concentration of 0.5 and 1% after 10 and 5 minutes respectively). In addition, iodophor 2% is effective against E. coli (at a concentration of 1% after 20 minutes) and Sal. typhimurium (at concentrations of 0.5 and 1% after 20 and 10 minutes respectively). It can be concluded that the environment plays a dangerous role in maintaining the infectious agents responsible for diarrhoea in calves.