Bovine Respiratory Disease (BRD): NAVLE Study Guide

BRD is the most economically important disease in the beef cattle industry and one of the highest-yield topics on the NAVLE. Know the pathogens, know the scoring system, know when to use tulathromycin versus florfenicol, and know what metaphylaxis means. That's most of what the exam tests here.

The disease is a synergistic process. Viral pathogens hit first — damaging the mucociliary escalator, suppressing local immunity, and priming the lung for bacterial invasion. The bacteria that follow are the ones that kill. Understanding that two-step sequence explains most of the clinical picture and most of the exam questions.

The Pathogens

BRD involves a predictable cast of bacterial and viral agents. The exam expects you to know each one's specific niche in the disease complex.