Study on microbial diversity of calf intestine

Calf diarrhea caused by bacteria usually begins to occur 2-3 days after birth. The main pathogenic bacteria are Escherichia coli, Campylobacter, Salmonella, Clostridium perfringens and so on. The pathogenic Escherichia coli is the main bacterium that causes diarrhea in calves. It invades the body of calves and releases enteric toxins to cause diarrhea in calves. The incidence of calf diarrhea caused by pathogenic Escherichia coli O1 can reach 60-70%, even as high as 90-100% in large-scale breeding calves, and the mortality rate can reach more than 50%. Therefore, the prevention and treatment of calf diarrhea is extremely important. We established a calf diarrhea model by artificially interfering with the colonization of intestinal microflora, and studied the effects of pathogenic E.coli on intestinal barrier and immune function of calves, providing theoretical basis for healthy breeding of calves and prevention of pathogenic E.coli diarrhea.