An overview of calf diarrhea - infectious etiology, diagnosis, and intervention

Cho, Yong-il; Yoon, Kyoung-Jin

Clinical (e.g., age, vaccination record, and clinical signs) and farm history should be provided to clinicians for determining the cause of diarrhea. Once the specimens are submitted to a veterinary diagnostic laboratory, the diagnostician sorts the samples to ensure proper delivery to testing laboratories based on the history and sample type. Generally, fecal sample are examined by microscopy (for C. parvum and Coccidia), bacterial culturing (for Salmonella spp., E. coli, and C. perfringens), and PCR (for BRV and BCoV). In contrast, intestinal tissues are subjected to immunohistochemistry or bacterial culturing. More recently, nucleic acid-based techniques such as PCR and an antigen-capturing enzyme-linked immunosorbent assay (Ag-ELISA) have been more commonly used for the rapid detection of various bacterial and viral pathogens in clinical specimens from diarrheic calves. When the laboratory test results are available, clinicians should consider the overall farm and clinical history in conjunction with lab results before identifying the causative pathogen.