Proinflammatory Cytokines, Type I Interferons, and Specialized Proresolving Mediators Hallmark the Influence of Vaccination and Marketing on Backgrounded Beef Cattle.

Cattle marketed through auction market systems and/or that remain unvaccinated are considered higher risk for BRD, but impacts on host response remain unclear. We sought to identify specific genomic patterns of beef calves vaccinated against BRD viruses or not and commercially marketed or directly transported in a split-plot randomized controlled trial. Forty-one calves who remained clinically healthy from birth through backgrounding were selected (randomly stratified) from a larger cohort of cattle (n = 81). Treatment groups included VAX/DIRECT (n = 12), VAX/AUCTION (n = 11), NOVAX/DIRECT (n = 7), and NOVAX/AUCTION (n = 11). Blood RNA was acquired across five time points, sequenced, and bioinformatically processed via HISAT2 and StringTie2. Significant transcriptional changes (FDR < 0.05) were observed at backgrounding entry (T5) in NOVAX/AUCTION cattle exhibiting 2809 uniquely differentially expressed genes and relative activation of immune, inflammatory, and metabolic pathways with upregulation of interferon-stimulated genes (e.g., IFIT3, MX2, and TRIM25) and downregulation of specialized proresolving mediator (SPM) enzymes (ALOX5 and ALOX15). VAX/AUCTION cattle exhibited modulated immune activation and preserved expression of SPM-associated genes when compared to NOVAX/AUCTION cattle. Both marketing route and vaccination shape the molecular immune landscape during high-stress transitions, with preweaning vaccination potentially modulating this response. This study provides mechanistic insight into how management practices influence immunological resilience and highlights the value of integrating transcriptomics into BRD risk mitigation.