Coccidiosis is a diarrheal infection that is a major cause of economic and productive loss to cattle producers worldwide. Bovine viral diarrhea virus and Cryptosporidium parvum are other possible etiologic agents for calf diarrhea. This study aims to examine the influence of liver vitamin and mineral levels – primarily selenium – on the severity of coccidiosis in calves. Relationships between coccidiosis and concurrent bovine viral diarrhea virus or Cryptosporidium spp. infections were also explored.