In the conditions of the Republic of Belarus there was determined the therapeutic efficacy of combined application of a complex antibacterial veterinary drug (containing lincomycin and spectinomycin) and Trivitim for the treatment of calves with respiratory diseases. In course of the study of 12 1-1,5 month old calves with respiratory diseases there were analyzed the hematological blood indexes, white blood cell differential and content of total protein in blood serum before the beginning of treatment and on the seventh and fourteenth days after beginning treatment. Research results showed that application the antibacterial veterinary drug in complex therapy with Trivitim in treatment of calves proved to be efficient. Their administration shortened the terms of recovery and prevented animal death as well as promoted the normalization of hematological and biochemical blood indexes.

In the conditions of the Republic of Belarus there was realized creation and evaluation of growth activity of serum and albuminous nutritional media. In the experiment there were used of 6 pathogenic strains: Leptospira pomona; Leptospira tarassovi; Leptospira grippothyphosa; Leptospira icterrohaemorragia; Leptospira conicola; Leptospira sejroe. For the Leptospira cultivation there were used the following media: serum-supplemented vitaminized medium on the basis of buck serum; serum-supplemented medium with a growth factor; serum-supplemented vitaminized medium with antlbody biosynthesis growth factor; semisynthetic Russel's medium in modification of V.I. Sitkov. Research results showed that the albuminous nutritional medium provided an intensive accumulation of Leptospira of all tested serogroups of Leptospira, but was suitable only for single bacterial inoculation. For the secondary hatching the albuminous media was unsuitable as it lowered the antigenic activity of Leptospira.

In the conditions of the Republic of Belarus there was realized a cultivation of pasteurellas by different methods in Hottinger broth in 37 deg C temperature in course of 24 hours. Tissue culture properties were studied in accordance with the character of bacteria growth in liquid nutritive media and at the agar surface. Research results showed that in 7 hours after cultivation in media with application of shuttel apparatus and addition of glucose it was possible to obtain the highest quantity of viable pasteurellas with a high degree of virulence. The obtained culture on the basis of obtained results was proposed to be used for the production of virulence antigen.