Bovine Respiratory Disease (BRD) costs the cattle industry in the United States as much as $3 billion annually [4, 5] . BRD is the outcome of complex interactions among host, environment, bacterial, and viral pathogens [6] . Histophilus somni, a gramnegative, pleomorphic species, is one of the important causative agents of BRD [6] . H. somni causes bovine infertility, abortion, septicemia, arthritis, myocarditis, and thrombotic meningoencephalitis [7] . H. somni strain 2336, the serotype used in this study and isolated from pneumonic calf lung, has a 2.2 Mbp genome and 2044 predicted open reading frames (ORFs), of which 1569 (76%) have an assigned biological function.