[Immune response of calves following vaccination with Paramyxovirus parainfluenzae-3 and adenovirus-1 under different colostral immunity stresses].

Studied was the immune response of calves, with colostrum antibodies and without colostrum antibodies, immunised with different dosages of live bivalent vaccine against P. parainfluenzae-3 and Adenovirus-1. For the group of calves with colostrum immunity, after single hypodermic immunisation with doses from 10(4) till 10(5) CPE50/cm3 for adenovirus, was not proved immune response, as a result of blocking of the vaccinal antigen of colostrum antibodies. For calves which missed these antibodies, the immune response was determined at the 15th day after the first vaccination with the lesser dose of bivaccine. Regardless of the degree of the antibodies of the calves, after the second vaccination (with the big and the little dose) was proved immune response, which does not differ considerably for the separated groups of calves. It was established, that the optimal dose, necessary for the calves to build an immunity at an early age (from 1 to 3 months), when immunised with bivaccine, was 10(4) CPE50/cm3 for the P. parainfluenzae-3 and 10(3) CPE50/cm3 for the Adenovirus-1. The bigger dose is useless not only from the economic point of view, but from the danger of provoking an unwanted shock of the vaccinated calves.