Abstract
470 pathological materials from dead birds were collected at poultry farms in Almaty, Zhambyl, Kyzylorda, Aktobe, Mangystau, Semipalatinsk, East Kazakhstan, Kostanay regions, 11 Pasteurella isolates were collected from them and pasteurella was studied in comparison with industrial strains. Of all the isolated and studied pasteurella strains, only Pasteurella multocida A biovar avium B-0054 No. 12, «Kazakh Scientific Research Veterinary Institute», G-5, Al-7, D-2, K-30, A-22 were classified as S-shaped. As a result of studying the pathogenic properties of pasteurella, the maximum pathogenic activity was observed in the Pasteurella multocida strain and biovar avium B-0054 No.12 «Kazakh Scientific Research Veterinary Institute», which ranged from 4 to 10,000 colony-forming activities (CFA) and amounted to LD50 from 2-4 CFA. Based on the study of the biological properties of epizootic Pasteurella strains, criteria for evaluating the biological properties of industrial Pasteurella multocida strains and the principles of their selection were studied and found. In the process of studying the biological properties of pasteurels in industrial conditions, their pathogenicity and immunogenicity can be determined. The effectiveness of the pasteurellosis erythrocyte antigen diagnosticum also showed that these two properties are directly related.