SPECIFIC PREVENTION OF ACUTE INTESTINAL DISEASES IN CALVES
The aim of the article was to study and evaluate the immunogenicity of the vaccine against colibacteriosis, streptococcosis and enterococcal infection in experiments on pregnant cows and newborn calves. The biological preparation included pure cell cultures of epizootic Escherichia coli strains producing thermolabile, thermostable toxins and shigalike toxins (verotoxins) and culture media containing cells of the hemolytic strains of Streptococcus bovis and Enterococcus faecalis. Pregnant cows were immunized twice in various doses in order to determine the optimal amount of preparation. An OKZ vaccine was used as a positive control. Ather vaccinations, blood serum was taken from pregnant animals, newborn calves, and colostrum was examined for the presence and amount of specific antibodies. Research results have shown the high immunogenicity of the new vaccine. The use of a double vaccination with a dosage of 5 and 10 cm3 with an interval of 10 days 30 days before delivery was the most optimal. The level of antibodies increased ather each administration of the drug (1: 89.6 ather the first vaccination, 1: 128 - ather the second one), reaching its maximum in colostrum ather calving (1:170.6). The OKZ vaccine showed lower immunogenicity results compared with the test product. In calves, on the 3rd day ather birth, the antibody titer was in the range 1: 24.8-1: 60.4. Thus, the vaccine against colibacteriosis, streptococcosis and enterococcal infection when used in pregnant cows has a high immunogenic activity against the most common pathogens of acute intestinal calves infections