No abstract

Highlights Multicentre field trials with natural pathogen exposure complement challenge trials. Beef calves housed with their dams were assessed for bovine respiratory disease (BRD). Two commercial intranasal live vaccines for BRSV-bPI3V were evaluated. New Vaccine A demonstrated non-inferiority compared to benchmarked Vaccine B. Difference in BRD prevalence between Vaccines A and B was −0.4% (95% CI −1.6 to 0.8%).