Tulathromycin possesses in vitro activity against Mannheimia haemolytica, Pasteurella multocida, Histophilus somni and Mycoplasma bovis, and Actinobacillus pleuropneumoniae, Pasteurella multocida, Mycoplasma hyopneumoniae, and Haemophilus parasuis the bacterial pathogens most commonly associated with bovine and swine respiratory disease, respectively.