ETIOLOGICAL STRUCTURE OF MIXED GASTROINTESTINAL AND RESPIRATORY DISEASES OF CALVES IN DAIRY FARMS AND COMPLEXES OF VOLOGDA REGION
The article refiects epizootological, statistical, bacteriological, virological, serological and molecular genetic research results. Within ten years, the specific weight of the incidence of the large cattle was 48.8±0.7%, of young animals - 48.6±6.7%. The speci c weight of mortality for the same period was 10.0 ± 3.6%. Of the cases, 40.9% die at the age from birth to 10 days, 30.4% die from 11 to 30 days, and 18.3% of calves die from one to three months. 144 studies were conducted, including: 30 ELISA (10 faecal samples, 20 serological blood serum samples), 33 molecular genetic (PCR), bacteriological - 81 samples of biomaterial from dead and sick animals. 159 cultures of microorganisms have been identified. According to the results of the ELISA, antigens of the causative agents of coronavirus, rotavirus, the causative agent of viral diarrhea were not detected. Antibodies to VD-BS were detected in 40%. The PCR method in 24.3% of the samples revealed the genome of herpesvirus type 5 in ushes from the nasal cavity of the calves. As the result of bacteriological studies, microorganisms in associations were more often isolated (29.6%). The identified bacteria of the Enterobarteriaceae family are assigned to the following species: Proteus (9.4%), Citrobacter (7.6%), Enterobacter (2.5%), E. coli (8.8%). The frequency of isolation of Escherichia serogroups was O32 - 20.0%, O152 - 15.6%, O6 - 22.3%. The remaining E. coli cultures not typed by O-antigen were pathogenic to white mice. The sensitivity of isolated microorganisms to antibiotics was determined.