The Impact of Vaccination Practices in Cow–Calf Operations on Bovine Respiratory Disease Morbidity and Mortality in Beef Calves: A Rapid Scoping Review

Background: Bovine respiratory disease (BRD) drives antimicrobial use in cow–calf herds and feedlots. This rapid scoping review evaluated vaccination of North American beef dams or pre-weaning calves against respiratory pathogens and subsequent calf health. Methods: Five databases and gray literature sources were searched for English-language North American trials and observational studies published since 2000. Data were charted in Excel and independently reviewed. Results: Twenty-eight studies reported clinical outcomes. One of seven field trials of pre-weaning calf vaccination reported pre-weaning clinical benefit; two of six reported post-weaning benefit. Four of ten calf vaccination challenge trials reported clinical differences. Two of six observational studies of dam vaccination reported beneficial pre-weaning associations. Post weaning, one dam vaccination challenge trial reduced pathogen shedding without improving clinical outcomes, while one cohort reported favorable feedlot associations. Two of the three field trials with beneficial clinical findings evaluated vaccines targeting pathogens previously associated with disease in the study herd. Observational evidence from multicomponent programs could not isolate vaccination effects. Conclusions: Evidence did not identify a consistently effective vaccination protocol. Benefits may depend on herd disease history, pathogen targets, disease pressure, and management context. Trials should evaluate clearly defined protocols in relevant settings and report absolute and relative effects with confidence intervals.