Interpretive Summary: Short communication: evaluation of an endotoxin challenge and intraruminal bacterial inoculation model to induce liver abscesses in Holstein steers

By: Zach S McDaniel, Kristin E Hales, T G Nagaraja, Ty E Lawrence, Raghavendra G Amachawadi, Jeff A Carroll, Nicole C Burdick Sanchez, Michael L Galyean, Taylor M Smock, Michael A Ballou, Vinicius S Machado, Paul R Broadway

Liver abscesses in feedlot cattle can cause a decrease in feed intake, average daily gain, feed efficiency, and hot carcass weight. At harvest, liver abscesses result in liver condemnations, carcass trimming, and a potential decrease in quality grade, with an estimated economic cost to packers of $41.6 million annually. Our objective was to evaluate an intravenous endotoxin challenge followed by intraruminal inoculation of bacteria commonly isolated from liver abscesses over a 10-d period as a potential model to understand the genesis and etiology of liver abscesses in cattle and evaluate possible preventative interventions. Results suggest that an endotoxin challenge in combination with intraruminal bacterial inoculation is not a viable model to induce liver abscesses in steers, and bacterial inoculation alone was insufficient to induce liver abscesses. The length of time necessary to induce liver abscesses is also unknown. Based on our results, more research is needed to develop a noninvasive model to induce liver abscesses in cattle.