INFLUENCE OF ROUTE OF VACCINE ADMINISTRATION AGAINST EXPERIMENTAL INTRAMAMMARY INFECTION CAUSED BY ESCHERICHIA-COLI

The route of immunization of a commercially available Escherichia coli J5 bacterin was investigated. Jersey cows were randomly assigned to o ne of three treatment groups: 1) unvaccinated (control), 2) vaccinated subcutaneously in the neck, and 3) vaccinated in the area of the supr amammary lymph node. Cows were vaccinated at drying off and at 2 wk pr ior to anticipated calving. Two quarters of each cow were challenged w ith approximately 60 cfu off. coli at 14 d postcalving. Route of immun ization in the neck or the area of the supramammary lymph node did not influence severity of coliform mastitis. However, the mean number of colony-forming units off. coli recovered from challenged quarters was significantly lower for vaccinated cows than for control cows at 24 h postchallenge. A quicker milk yield recovery following intramammary ch allenge was also observed for vaccinated cows. Serum immunoglobulin (I g) G, IgG(1), and IgG(2) and whey IgG(1) and IgG(2) antibody titers ag ainst E. coli J5 whole-cell antigens were significantly enhanced in va ccinated cows. Somatic cell counts in milk from challenged quarters an d rectal temperatures following intramammary challenge were not differ ent for cows across treatment groups. Immunization did not prevent int ramammary infection.