In two farms (A and B) losses of calves in the first 2—3 days after birth caused by diarhhoea were 25,2% and 36,5%. Bacteriological examinations of the intestines revealed an especially high concentration (2,4 X 10⁹ — 3,6 X 10¹⁰ cells/g) of the highly toxinogenic „in vitro” C. perfringens A. Contents of intestines were, however, free of lethal toxins. Examinations of pathological properties of C. perfringens A isolates showed that they produced strong alpha, theta and kappa toxins, and the majority of isolates additionally produced mi and ni toxins. Lack of toxins in the intestines may result from their quick binding with body tissues. This observation is confirmed by the high effectiveness of prophylatic measures i.e. immunization of animals against alpha toxin (article in preparation). The result point to the role of nonenterotoxinogenic strains of C. perfringens A, producing alpha toxin, in the etiology of diarrhoea of newborn calves.
Diarrhea in neonatal calves is still considered a serious clinical problem, especially in large dairy herds. The aim of this study was to investigate etiological agents responsible for this disease in large dairy herds in Poland. Four herds in northwestern Poland were studied. During the investigation 375 cows delivered 391 calves. Calves in this study were observed until the age of 14 days. Symptoms of diarrhea were observed in 135 of them. Incidence of diarrhea in each herd was respectively 11.4%, 12.5%, 61.4% and 55.8%. The disease did not take a serious course in these calves nor were any fatal cases observed. The investigation of fecal samples taken from calves with diarrhea showed an absence of E. coli K99 and Salmonella sp. Antigens. A coronavirus infection was observed in only one herd. The presence of antigens of rotavirus and cryptosporidium has been confirmed in all herds. The confirmation of viruses (rotavirus or coronavirus) as the sole cause of the disease has been confirmed in 7.8% calves with diarrhea. The majority of cases of diarrhea (25.5%) was caused by a combination of viruses and Cryptosporidium spp. Primarily the combination of rotavirus and Cryptosporidium spp. was diagnosed (23.5%) and far less frequently the combination of coronavirus, rotavirus and Cryptosporidium spp. (2.0%). The disease caused only by Cryptosporidium spp. showed mild symptoms. Results of the study confirmed that proper management and sanitary conditions in keeping the animals are very important in the prophylactics of diarrhea in neonatal calves.