Association between infection of the respiratory tract attributable to bovine coronavirus and health and growth performance of cattle in feedlots

Objective-To determine the association between respiratory tract infection with bovine coronavirus (BCV), treatment for respiratory tract disease, pul monary lesions at slaughter, and average daily gain in cattle in feedlots. Animals-837 calves in feedlots in Ohio and Texas. Procedure-Nasal swab specimens were obtained from cattle at arrival in a fe edlot (day 0) and at various times during the initial 28 days after arrival . Specimens were tested for BCV, using an antigen-capture ELISA. Serum samp les were obtained at arrival and again 28 days after arrival and tested for antibodies to BCV, using an antibody-detection ELISA. Information was coll ected regarding treatment far cattle with respiratory tract disease and ave rage daily gain during the feeding period. Pulmonary lesions were evaluated at slaughter. Results-Cattle shedding BCV from the nasal cavity and developing an antibod y response against BCV were 1.6 times more likely to require treatment for respiratory tract disease than cattle that did not shed the virus or develo p an immune response against BCV. Additionally, cattle that shed BCV from t he nasal cavity were 2.2 times more likely to have pulmonary lesions at sla ughter than cattle that did not shed the virus. The BCV shedding or serocon version status did not affect average daily gain. Conclusions and Clinical Relevance-Bovine coronavirus infects feedlot cattl e and is associated with an increased risk for cattle developing respirator y tract disease and pulmonary lesions. Development of appropriate control m easures could help reduce the incidence of respiratory tract disease.