Coccidiosis associated with post-weaning diarrhoea in beef calves in a dry tropical region

Abstract
The roles of helminths and coccidia in post-weaning diarrhea in beef calves in the dry tropics were investigated. Diarrhea occurred approximately 1 mo. after weaning in both anthelmintic treated and untreated calves. The highest numbers of coccidial oocysts were seen 29 days after weaning and 3 necropsies confirmed Eimeria zuernii coccidiosis. In the absence of wet overcrowded conditions, disease may have been precipitated by environmental interactions leading to suppression of host immunity. Other Eimeria identified were E. bukidnonensis, E. wyomingensis, E. bovis, E. auburnensis, E. cylindrica, E. ellipsoidalis and E. subspherica. The last 5 spp. are believed not to have been previously documented in Australia. The presence of E. canadensis was strongly suspected.