Diarreia em bezerros na região sul do Rio Grande do Sul

Abstract

This dissertation is a study of enteric disorders in calves diagnosed in southern Brazil in 36 years. It is presented a study with the description of the main causes of diarrhea in calves. Parasitic and the bacterial causes are the most prevalent. Ninetyfour cases of calves with diarrhea were diagnosed, of these, 44.7% were of parasitic causes and 34.0% of bacterial causes. Diarrhea of parasitic cause was the most important in southern Brazil and affected calves from three to 12 months of age. Another study is also presented, describing the epidemiological, clinical signs and pathology of an outbreak of cryptosporidiosis in calves in southern Brazil. Thirty-five out of 400 calves with 30-45 days of age were affected and 16 died. The calves were born weak and just after birth, they had yellow diarrhea, weight loss, dehydration, depression, and death between 10 and 15 days after onset of clinical signs. Congestion of the bowel and mesenteric blood vessels were observed at necropsy. Intestinal distension by gas and dilation of lymphatic vessels were also observed. Microscopically, the intestine showed flattening of the villi with necrosis and atrophy. Adhered to the surface of the villus epithelial cells there were round basophilic structures of 2- to 5-μm diameter compatible with Cryptosporidium spp. The electron microscopy revealed the presence of different stages of the agent adhered to the microvilli of enterocytes. Cryptosporidiosis is an important cause of diarrhea in calves not only as an opportunistic agent, but also as a primary agent of diarrhea in calves.