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

Cho, Yong-il; Yoon, Kyoung-Jin

Calf diarrhea is attributed to both infectious and non-infectious factors [8, 62] . Multiple enteric pathogens (e.g., viruses, bacteria, and protozoa) are involved in the development of this disease. Co-infection is frequently observed in diarrheic calves although a single primary pathogen can be the cause in some cases. The prevalence of each of pathogen and disease incidence can vary by geographical location of the farms, farm management practices, and herd size. Although the cattle industry has made great improvements with herd management, animal facilities and care, feeding and nutrition, and timely use of bio-pharmaceutics, calf diarrhea is still problematic due to the multi-factorial nature of the disease. Prevention and control of calf diarrhea should be based on a good understanding of the disease complexities such as multiple pathogens, co-infection, environmental factors, and feeding and management during the calving period before disease outbreaks. In this overview, infectious agents involved in calf diarrhea, appropriate application of diagnostic methods for identifying these pathogens, and intervention strategies for managing calf diarrhea are described. The article consists of three sections. The first section presents the characteristics of major enteric pathogens known to cause calf diarrhea (i.e., bovine rotavirus (BRV), bovine coronavirus (BCoV), bovine viral diarrhea virus (BVDV), Salmonella (S.) enterica, Escherichia (E.) coli, Clostridium (C.) perfringens, and Cryptosporidium (C.) parvum) along with newly emerging enteric pathogens such as bovine torovirus (BToV) and caliciviruses (bovine norovirus [BNoV] and Nebovirus). In the second section, proper sampling and handling techniques (e.g., sample collection and delivery to a diagnostic laboratory) as well as various laboratory diagnostic methods are reviewed along with their advantages and disadvantages. The last section includes a discussion of prevention and control strategies for calf diarrhea that involve multiple factors such as peripartum calving management, calf immunity, and environmental stress and contamination.