Bacterial cell lysates of E. coli strains (K99 and O 157) were prepared and used as vaccinal antigens
added to locally prepared Entero-3 inactivated vaccine components aiming to improve the immune
response of calves against E. coli. Three groups of apparently healthy crossbred, three calves per group,
were vaccinated with two doses (4ml I/M /dose), three weeks apart as follow: the first group (G.Ι) was
vaccinated by local inactivated Entero-3 vaccine (Rota, Corona and E. coli K99). The second group
(G.ΙΙ) was vaccinated by vaccine containing Rota, Corona and cell lysate of E. coli K99 & E. coli O157.
The third one (G.ΙΙΙ) was vaccinated by vaccine containing Entero-3 vaccine component and cell lysate
of E-coli K99 & E-coli O157, and the fourth group kept unvaccinated served as control. The antibody
response in sera of vaccinated calves measured by serum neutralization test (SNT) and ELISA, which
revealed that all types of the prepared vaccines induced a protective antibody titres. Entero-3 vaccine
containing cell lysate of E-coli strains induced higher response than the other two vaccines. In
conclusion, adding of E. coli strains lysates as a vaccinal antigen to the locally prepared Entero-3
vaccine, provided a formulation of Entero -3 vaccine that conferred a good immune response of calves
against collibacellosis