The Use of an Experimental Vaccine in Gestating Beef Cows to Reduce the Shedding of Escherichia coli O157:H7 in the Newborn Calf1

Beef cows in the last trimester of pregnancy were used to determine if vaccinating against Escherichia coli O157:H7 would increase antibody titers in the serum and also result in the transfer of these antibodies to the neonatal calf. Seventy-one cows were vaccinated 30 d before parturition with an experimental vaccine and then commingled with 66 nonvaccinated cows. Cow fecal and venous blood samples were collected at trial initiation and again about 14 d after parturition. Calf feces and serum were collected at about 14 d after parturition and 60 d later. The serum was analyzed for antibody titers to E. coli O157:H7, and the prevalence of E. coli O157:H7 in feces was determined by the Barkocy-Gallagher procedure. Initial cow antibody titers to E. coli O157:H7 were not different (P = 0.50) between treatments, but by parturition, the antibody titers for E.coli O157:H7 in vaccinated cows were 11 times higher (P < 0.001) than for control cows (917 vs. 83). The serum titers for calves suckling vaccinated cows were higher (P < 0.001) than control calves (1,485 vs.135) at about 14 d after calving. By 60 d, titer levels were still higher (P < 0.001) for calves suckling vaccinated cows. Initial fecal E. coli O157:H7 concentrations for cows were negative for both treatments and remained low. There were no differences in fecal E. coli O157:H7 at 60 d postpartum among calves; less than 5% of calves were shedding. Results suggest that vaccinating gestating cows for E. coli O157:H7 resulted in elevated antibody titers cows, and these antibodies transferred to the calf.