Bovine Liver Abscesses – NAVLE Study Guide

Overview and Clinical Importance

Liver abscesses are discrete, circumscribed focal sites of bacterial infection within the hepatic parenchyma, representing one of the most economically significant diseases in the feedlot cattle industry. This condition results from bacterial translocation from the gastrointestinal tract, primarily the rumen, through the portal circulation to the liver.

The disease is intimately connected to modern feeding practices, particularly high-grain finishing diets that predispose cattle to ruminal acidosis and subsequent rumenitis. This forms the classic "acidosis-rumenitis-liver abscess complex" that every NAVLE candidate must understand.

Etiology and Microbiology

Primary Pathogen: Fusobacterium necrophorum

Fusobacterium necrophorum is a Gram-negative, non-spore-forming, obligate anaerobic bacterium and a normal inhabitant of the bovine rumen. It is the primary etiologic agent isolated from liver abscesses in approximately 80-100% of cases.