Etiology and diagnosis of the gastrointestinal and respiratory diseases of calves in the farms of the Vologda region

Abstract

The article reflects the statistical, bacteriological, virological and molecular genetic research results. In 2019, the proportion of gastrointestinal pathologies in the total incidence of young animals was 37.6 + 0.7%. On average, over the past five years, 46.6 + 0.7% of born calves have been ill. Gastrointestinal diseases are recorded mainly in young animals under the age of 3 months. Of the number of cases, 43.3% die from birth to 10 days, 31.7% from 11 to 30 days, and 15.8% of calves from one to three months. The proportion of infectious diseases is 0.36% of the total incidence of animals. 152 studies were carried out, including: 39 fecal specimen by ELISA, 30 molecular genetic (PCR), bacteriological - 83 samples of biomaterial from dead and sick animals. 107 microorganism cultures have been identified. According to the ELISA, the most frequently detected antigens were causative agents of coronavirus - 33.3%, rotavirus - 30.8%, the causative agent of viral diarrhea - in 15.4% of cases. In 96.8% of cases, the causative agents of viral infections were identified in the associations: coronavirus and rotavirus (43.3%), coronavirus, rotavirus and viral diarrhea (36.7%), coronavirus and viral diarrhea (20.0%). In 22.2% of the samples, PCR was used to detect the herpes virus type 5 gene in rinses from calves's nasal cavity. As a result of bacteriological studies, a change in the spectrum of cultures of microorganisms isolated from pathological material was noted. The percentage of unidentified crops decreased by 2.6 times. Given the results, we propose to include in the scheme of diagnostic studies for mixed infections additional studies: feces for viral infections by ELISA; crops of primary pathological material and feces should be carried out additionally on accumulation media; PCR analysis of swabs from the nasal cavity, blood; during bacteriological examination, consider the allocation of microorganisms: Pseudomonas, Streptococcus, Staphylococcus.