Specific features of distribution and manifestation of cryptosporidiosis of calves on dairy complexes in Siberia

Abstract

The results of the study of specific features of distribution and clinical manifestation of bovine cryptosporidiosis in association with pathogens of viral and bacterial nature are presented. From 2014 to 2023, 666 samples of biomaterial (tracheal mucosa, lungs, mediastinal and mesenteric lymph nodes, contents of rennet and intestine) collected from fallen and forcefully killed calves under 6 months of age with signs of enteritis and respiratory diseases were examined. 94 farms of six regions, two territories of the Siberian region and the Republic of Kazakhstan were surveyed. The findings confirm the widespread prevalence of Cryptosporidium in calves. Cryptosporidium parvum oocysts were most frequently detected and were present in 34 (5.1%) samples of biological material from calves in 22 (23.4%) of the surveyed farms. It was found that oocysts were rarely (22.7%) present in monovariant in animals, more often (77.3%) they were found in associations with viruses and bacteria during outbreaks of viral-bacterial infections. Young animals under 30 days of age are most susceptible to infection. Newborn calves are most susceptible to infection with oocysts, and those animals that have had the disease become lifelong sources of the pathogen for susceptible animals. Cryptosporidiosis is an independent disease and runs independently of the presence of the viruses and bacteria in the body and has no synergistic interaction with them, but the presence and multiplication in the body of animals of this pathogen contributes to the severity of the course of enteritis in calves and leads to difficulties in the treatment and preventive measures. The presence of Cryptosporidium in animals should be taken into account when carrying out complex anti-epizootic measures.