An inactivated whole cell vaccine, containing M. paraturberculosis suspended in oil was administered to calves in the first month of life since 1984 in 2 farms with a culling rate for clinical paratuberculosis of 5% or more. The unvaccinated cows and calves present on the farms were the control groups. After slaughtering, the intestinal tract and adjoining lymph nodes were investigated for paratuberculosis using pathohistology, Ziehl Neelson staining and culture on Smith, and Lowestein Jensen culture tubes. The results indicate that 11.8% of the control group (340 animals) had histological and/or cultural signs of paratuberculosis, while in the vaccinated group (159 animals) only 5.0% were positive.