ABSTRACT
Introduction: Neonatal calf diarrhoea is a multifactorial disease that sometimes leads to high economic losses. It can be fatal due to dehydration and acidosis and has been one of the main causes of calf mortality. Material and methods: This retrospective study considered calves of a maximum of 35 days of age and with a diagnosed infection with rotavirus and/or bovine coronavirus. We examined the clinical records of 156 calves that were referred to the University Clinic for Ruminants in Vienna. Results Calves that had been treated with antibiotics before admission to the Clinic had a higher risk of staying longer, suggesting either that these calves had a more serious illness or that antibiotic treatment was not indicated and so therapeutic success was not achieved. Twenty-three calves died or were euthanized at the Clinic. At the time of admission, they were younger than the surviving calves and they had a lower inner body temperature and a lower base excess at the first examination. The four most common pathogens in faecal samples were rotavirus, bovine coronavirus, Cryptosporidium parvum and Escherichia coli, which were detected in 67.1%, 53.9%, 48.1% and 94.1% of the faecal samples examined. The most common co-infection was rotavirus with Cryptosporidium parvum (17 faecal samples). We inspected the four most common pathogens in more detail. There were significant correlations between bovine coronavirus and season, with the risk of suffering from bovine coronavirus 1.6 times higher in winter than in other seasons. There was also a correlation between Cryptosporidium parvum and general behaviour: the risk of being infected with Cryptosporidium parvum was 2.6 times higher in calves that were moderately to severely depressed at the first examination. There was a correlation between co-infections and mortality, with calves with a co-infection at three times higher risk of dying than calves with a mono-infection.