Abstract
A case-control study was designed to investigate the role of different Cryptosporidium spp. in Swedish dairy herds with and without calf diarrhoeal problems. Faecal samples were collected from preweaned calves, young stock and cows. Cryptosporidium oocysts were detected by sodium chloride flotation and epifluorescence microscopy. Molecular diagnostics were used to identify Cryptosporidium species. Samples containing C. parvum were further analysed to determine subtypes. Calf faecal samples were also analysed for rotavirus, coronavirus and Escherichia coli F5+. Total protein was assessed in 1- to 8-day-old calves. A questionnaire was used to identify differences in management routines. Cryptosporidium infection was diagnosed in all herds, with equal prevalence in case and control herds in all three age groups. Cryptosporidium parvum, Cryptosporidium bovis, Cryptosporidium ryanae and Cryptosporidium andersoni were all identified, as were rotavirus, coronavirus and E. coli F5+. C. ryanae and C. andersoni were only detected in non-diarrhoeal samples, whereas the other pathogens were detected in both diarrhoeal and non-diarrhoeal samples. Diarrhoea was more common in case herd calves. Disinfection of single pens was more common in case herds and several other management routines seemed to differ although results were not significant.