Immunological reactivity of calves with associated respiratory infections

摘要

Associated respiratory infections are a special type of infection. They have a combined effect on the organism. We conducted this study in order to determine impairment of immunological reactivity in calves aged from 5 days to 4 months for respiratory diseases caused by pathogen associations. Determination of etiological agents was carried out by a complex of diagnostic studies: clinical examination of calves, serological screening of paired blood sera from diseased calves; ELISA, PCR, microbiological, scatological and hematological studies. Among the examined animals, 19% had no clinical signs of the disease and there were no positive laboratory tests for the presence of pathogens. The etiological role in the development of respiratory diseases in calves belongs to the causative agent PI-3. Associating pathogens in the virus group are: rotavirus B bovine and Bovine herpesvirus 1. In the virus-bacteria group: E. coli 99. In the virus-bacteria and invasive group: rotavirus B bovine, E. coli 99 and Eimeria bovis. An index analysis of hemogram indices gives an idea of the complex changes in the immune system of calves with mixed respiratory infections. Mono-infections cause a moderate compensatory response of the organism. Endogenous intoxication with the "virus-bacteria" and "virus-bacteria and invasive" infections is expressed due to the poly-antigenic load on the body.