[Studies of immunity in mastitis in cows]

Studies were carried out to establish the specific antibodies in the milk and blood sera of cows recovered from a spontaneous infection of the udder caused by streptococci, staphylocci, Corynebacteria, and some representatives of Escherichia coli as well as of cows immunized with a polybacterial vaccine. Followed up was likewise the resistance of the udder in vaccinated cows to bacterial infections. It was found that in both groups of animals the specific antibodies' titer ranged from 1:80 to 1:1280. Cows vaccinated in the eighth month of pregnancy developed immunity that varied in its effect, however, was able to protect the udder during the following lactation from infection caused by the respective bacterial specie against which the vaccine was produced.