Mannheimia haemolytica is an important bacterial pathogen associated with bovine respiratory disease (BRD) in cattle. The economic losses it generates surpass those incurred by all other diseases of cattle combined, arising from production losses, treatment costs and mortalities. The most widely used method to control BRD is antibiotic administration. However, concerns regarding the use of antibiotics in agriculture and antibiotic-resistant bacteria have given rise to the search for new mitigation strategies. Current technologies for DNA sequencing allow for rapid bacterial genome analysis and comparison of similarities and differences between strains. It is our objective to sequence and compare the genomes of virulent and commensal strains of M. haemolytica in order to identify conserved antigens in virulent strains.  Once established, target antigens will be used to develop a vaccine offering cattle protection against M. haemolytica-associated BRD. By focussing on conserved traits in pathogenic strains, it may be more feasible to develop a vaccine with broad protection against M. haemolytica. Because several bacteria may be implicated in BRD, it is also our objective to use this project as a platform for developing vaccines against additional BRD-associated bacterial pathogens.