A Rapid Scoping Review of Nutritional Management of Beef Cows and Pre-Weaning Calves and the Occurrence of Bovine Respiratory Disease in Pre- and Post-Weaning Calves in North America.

Bovine respiratory disease (BRD) causes economic loss and antimicrobial use in North American beef production. This rapid scoping review examined whether nutritional management of beef cows and pre-weaning calves affects BRD morbidity or mortality before or after weaning. Eligible sources were English- or French-language North American studies published from 2000 onward that evaluated nutrition or colostrum management in beef cows or calves and reported BRD-specific, secondary, or tertiary outcomes. Six bibliographic databases and grey-literature sources were searched. One reviewer charted and verified data using a pre-tested form. Findings were synthesized narratively without formal critical appraisal. Forty-seven studies were included: 22 reported BRD-specific morbidity or mortality, 20 reported only secondary outcomes (e.g., crude mortality), and five reported only tertiary outcomes (e.g., vaccine antibody titres). Three of five controlled trials of maternal protein supplementation reported favourable offspring BRD outcomes, although incomplete comparisons, absent treatment effect estimates, and the absence of formal critical appraisal limited interpretation. Selected maternal trace mineral trials reported reduced post-weaning BRD morbidity or fewer aggregated sick incidents. Direct evidence for colostrum-management strategies was sparse; other findings were inconsistent or based on few or no BRD events. Evidence remains insufficient for specific recommendations. Adequately powered commercial trials should report prespecified BRD outcomes, effect sizes, and confidence intervals.