Liver abscesses and bovine respiratory disease (BRD) cause the greatest disease associated economic losses in the Canadian Beef Industry. As these conditions are mainly caused by Gram-negative bacteria, this combined with antimicrobial resistance (AMR) may account for the limited efficacy of current antimicrobials. This project will use “omic” technologies to characterize the interaction between these disease-causing microbiomes and the host in a relationship defined as the “microactome”. This project represents one pillar in a large AAFC project entitled Mitigating the development.