Epidemiology and Infection

Prevalence of Escherichia coli O157:H7 in range beef calves at weaning

W. W. LAEGREID a1c1, R. O. ELDER a1 and J. E. KEEN a1
a1 Animal Health Research Unit, US Meat Animal Research Center, USDA, ARS, P.O. Box 166, State Spur 18D, Clay Center, Nebraska 68933


This study was designed to determine the prevalence of Escherichia coli O157:H7 infection of beef calves at weaning, prior to arrival at the feedlot or mixing with cattle from other sources. Fifteen range cow-calf herds, which weaned calves in October and November, were sampled in Kansas, Missouri, Montana, Nebraska and South Dakota. Faecal culture for E. coli O157:H7 was performed and anti-O157 serum antibody titres were determined by blocking ELISA. Thirteen of the 15 herds (87%) were found to have at least one positive isolation of E. coli O157:H7 in faecal samples. Within positive herds, prevalence ranged from 1·7–20·0%, with an average of 7·4±6·2% S.D. of individual animals shedding E. coli O157:H7 in faeces. All herds had high prevalence of anti-O157 antibodies, ranging 63–100% of individuals within herds seropositive. This study indicates that E. coli O157:H7 infection before weaning, prior to entry into feedlots, is widespread. Furthermore, serologic evidence suggests that most calves (83%) and all herds (100%) have been exposed to E. coli O157.

(Accepted June 1 1999)

c1 Author for correspondence.