Acute anaplasmosis reduces breeding soundness in experimentally-infected beef bulls

Abstract

Bovine anaplasmosis is a source of significant economic and production loss to the cattle industry in the United States, costing a modest estimate of $300 million in losses annually. The causative agent of bovine anaplasmosis, Anaplasma marginale, places herd management and financial strains on cow-calf producers in the U.S., a majority of which exist in anaplasmosis-endemic areas. Bulls servicing these herds are considered most valuable for their ability to reproduce. Death or disease in bulls which impairs their reproductive ability has significant consequences for producers and their herds. Clinical anaplasmosis signs, such as hemolysis and fever, may reduce bull breeding soundness. The objective of this study was to evaluate changes in breeding soundness outcomes and clinical changes in beef bulls over the course of acute anaplasmosis, from prior to infection, throughout development of clinical disease, and upon recovery.