Prevention of experimentally induced enteric colibacillosis in newborn calves.

Severe enteric colibacillosis, characterized by profuse watery diarrhea, dehydration, apathy, hypothermia, and inability to stand, was produced in seven of eight newborn, colostrum-fed calves from nonvaccinated dams after oral challenge of calves with 10(11) viable cells of Escherichia coli strain B44. Twenty-nine of 32 calves from dams vaccinated with various preparations of E. coli strain B44 were protected against severe enteric colibacillosis after oral challenge. Calves were protected if the dams received two subcutaneous vaccinations prior to calving. Calves also were protected if the dams were given a homologous vaccine of live or killed whole cells or a broth culture supernatant vaccine via the subcutaneous and intramammary routes 1 year earlier. Nineteen of the 29 protected calves had a transient diarrhea.