[Studies on Salmonellosis in the calf. 5. Clinical testing of Smd-Salmonella-dublin vaccine for oral administration].

The oral vaccine, prepared on the basis of streptomycindependent mutants for administration to control S.-dublin infection, was clinically tested on 2,210 calves of 22 herds. The experimentally obtained findings regarding good tolerance and sufficient effectiveness of oral live vaccines were thus confirmed under field conditions. Good effectiveness of the oral vaccine was reflected in the recorded decline of clinical salmonellosis cases and of calf losses due to salmonellosis, and it was established also by bacteriological identification of S. dublin in faecal samples, histological sections, and material obtained from emergency slaughter carcasses. A comparison between this oral vaccine and "Mellavax" an imported vaccine for subcutaneous adminstration with good effectiveness, revealed superiority of the oral vaccine by almost all criteria of action. Particular importance was attributed to the significant reduction of the number of Salmonella-excreting animals (faeces) following oral immunisation. The oral vaccine against Dublin salmonellosis of calf was disembargoed for production in 1975 under the name of "Salmonella-dublin Live Vaccine Dessau".