Identification of methylation markers for age and Bovine Respiratory Disease in dairy cattle

Methylation profiles of animals is known to differ by age and disease status. Bovine respiratory disease (BRD), a complex infectious disease, primarily affects calves and has significant impact on animal welfare and the cattle industry, predominantly from production losses. BRD susceptibility is multifactorial, influenced by both environmental and genetic factors. We investigated the epigenetic profile of BRD susceptibility in calves and age-related methylation differences between healthy calves and adult dairy cows using Reduced Representation Bisulfite Sequencing (RRBS). We identified 3,452 genes within differentially methylated regions between calves and adults. Functional analysis revealed enrichment of developmental pathways including cell fate commitment and tissue morphogenesis. Between healthy and BRD affected calves, 964 genes were identified within differentially methylated regions. Immune and vasculature regulatory pathways were enriched and key candidates in BRD susceptibility involved in complement cascade regulation, vasoconstriction and respiratory cilia structure and function were identified.