Timely, accurate, and reliable laboratory tools are important for antimicrobial stewardship (AMS) in food animal production. The objectives of this study were to (1) identify factors that influence live animal respiratory sample collection for laboratory testing and (2) describe the potential for integration of laboratory testing of samples from live animals into an AMS strategy for bovine respiratory disease (BRD) management in Canadian feedlots. Utilizing focused ethnography, virtual key informant interviews were conducted with eight feedlot veterinarians from Alberta, Ontario, and Saskatchewan, Canada. Thematic analysis revealed four themes: (1) lived experience of feedlot veterinarians with laboratory testing for BRD pathogens and antimicrobial resistance (AMR), (2) evidence-informed BRD management that integrates multiple data sources and their components, (3) organizational factors that affect the uptake and use of laboratory tests, and (4) the role of laboratory testing to support AMS in BRD management. While sample collection and laboratory testing are commonly used for BRD and AMR research and surveillance, they are not routinely applied in everyday BRD management. Veterinarians identified key challenges with laboratory testing, including turnaround time, the need for clear benefits, practical implementation, and effective communication with feedlot managers. Laboratory testing must provide valuable, actionable insights to encourage its adoption in Canadian feedlot operations. If successful, such testing could support AMS and be used to justify antimicrobial use if this were to become a regulatory or market requirement.