Whole blood transcriptome analysis of feedlot cattle with and without bovine respiratory disease

In this study we aimed to identify differentially expressed (DE) genes involved in the host immune response to BRD using whole blood and RNA sequencing. Samples were collected from heifers (average arrival weight = 215.0 ± 5.3 kg) with (n = 25) and without (n = 18) BRD at a commercial feedlot in Western Canada. RNAseq analysis showed a distinct whole blood transcriptomic profile between BRD and non-BRD heifers. Further examination of the DE genes revealed that those involved in the host inflammatory response and infectious diseases pathways were enriched in BRD animals, while gene networks associated with metabolism and cell growth and maintenance were downregulated. Overall, the transcriptome profile derived from whole blood provided evidence that a distinct antimicrobial peptide driven host immune response was occurring in the animals with BRD. 43 samples were collected from 25 cattle diagnosed with BRD and 18 pen matched controls at one time point.