author(s)
Satish Kumar, VS Rajora and Niddhi Arora

abstract
Escherichia coli is incriminated as one of the important causal agent of mortality of new born dairy calves all over the world and reports from India indicate that this disease is prevalent even on organized dairy farms throughout the country. Diarrhoea producing E. coli possesses colonization antigens or adhesions that enable the bacteria to colonize the small intestines. The detection of E. coli enterotoxin provides the evidence that enterotoxin - producing E. coli (ETEC) has an etiological role, the expression of K99 fimbriae (or F5 ETEC) accounts for nearly all cases of ETEC infection found in newborn calves. In present study out of total 16 E. coli isolated samples, three isolates (18.75%) were found to be positive for the presence of lethal toxin (LT) gene, which PCR has shown 450bp amplified product confirming ETEC strain of E. coli.