Prevalence of enteric pathogens in the feces of healthy beef calves.

Fecal specimens from 136 healthy beef calves (1 day to 12 weeks of age) were examined for the presence of infectious agents known to cause enteric disease in calves. The calves were selected from 22 herds in which all calves were free of clinically apparent enteric disease. Salmonella sp, enterotoxigenic Escherichia coli, Cryptosporidium, and coronavirus were not detected in any of the calves. Three calves were infected with rotavirus and 1 calf was infected with Yersinia enterocolitica. Campylobacter-like bacteria were isolated from 50 of 130 calves, with 36 of the calves positive for C jejuni. Seemingly, clinically normal calves may be infected more often with enterotoxigenic E coli, Cryptosporidium, coronavirus, or rotavirus in herds in which some calves have enteric disease than in herds free of major enteric disease. Campylobacter jejuni was well adapted to the bovine host and was of similar prevalence in diarrheal and nondiarrheal calves. The K99 positive, nonenterotoxigenic E coli was isolated from the feces of 16 healthy calves. Information in addition to the presence of K99 antigen is useful when diagnosing enterotoxic colibacillosis in calves.