BACTERIAL INTESTINAL INFECTIONS OF YOUNG CATTLE

Abstract

Gastrointestinal infections of bacterial etiology occupy one of the main places in the pathology of young cattle. The article presents a literature review on the etiology, pathogenesis and clinical diagnosis of major bacterial intestinal infections in young cattle. The body of animals is constantly affected by a set of causes, which, due to violations of the technology of maintenance, care and feeding, playing the role of stress factors, leading to reduced nonspecific resistance, increased reactivity and bacteriosis in animals associated with gastrointestinal lesions. Up to 75 % of diseases of the digestive tract of young cattle are more likely to occur as associated infections caused by both viruses and bacteria. Viruses, multiplying in the mucous membrane of the gastrointestinal tract, cause dystrophy, necrosis and desquamation of epithelial cells, what promotes the colonization and penetration into the blood of pathogenic bacteria or their metabolites and the development of severe pathological processes. Bacterial agents that cause diarrhea or complicate viral infections include pathogenic Escherichia coli, Salmonella, Clostridium, Citrobacter, Enterococci, Yersinia, Pseudomonas, Campylobacter and others. A special role in the occurrence of diseases of the digestive tract in young cattle is played by opportunistic pathogens, which include bacteria of the family Enterobacteriaceae. The main intestinal infections of bacterial etiology of young cattle are colibacillosis, salmonellosis, anaerobic enterotoxemia of calves and campylobacteriosis. Calf colibacillosis is an acute infectious disease caused by enteropathogenic Escherichia coli, which is characterized by profuse diarrhea, septicemia, intoxication, dehydration and significant animal death. The causative agents of salmonellosis are bacteria of the family Enterobacteriaceae Salmonella dublin, S. enteritidis and S. typhimurium. Calves suffer from salmonellosis from the first days of life and up to 6 months of age, with a characteristic acute fever and diarrheal symptom complex. Anaerobic enterotoxemia of calves is an acute toxic-infectious disease of mainly newborn young, caused by the obligate anaerobic bacterium Clostridium perfringens, characterized by hemorrhagic-necrotic inflammation of the intestine, diarrhea and intoxication of the body. Campylobacter jejuni can cause diarrhea in calves. Campylobacteriosis with symptoms of enteritis mainly affects dairy calves, although C. jejuni can also cause enteritis in ruminant calves. Other bacteria that can cause enteritis in calves are Bacteroides fragilis, Chlamydophila psittaci, Klebsiella spp., Proteus spp., Yersinia enterocolitica and others.