Bovine White Muscle Disease Study Guide

Overview and Clinical Importance

White Muscle Disease (WMD), also known as nutritional myodegeneration (NMD) or nutritional muscular dystrophy, is an acute, degenerative disease of cardiac and skeletal muscle caused by dietary deficiency of selenium and/or vitamin E (alpha-tocopherol). This condition represents one of the most economically significant nutritional deficiency diseases affecting cattle worldwide, particularly in regions with selenium-deficient soils.

WMD occurs worldwide in areas where soil selenium content is low, resulting in deficient forages and grains. In the United States, selenium-deficient regions include the Pacific Northwest, northeastern and eastern seaboard states, the Great Lakes region, and parts of New England. The disease primarily affects young, rapidly growing calves, typically between birth and 4 months of age in dairy breeds, and up to 12 months in beef cattle.

Etiology and Pathophysiology

Role of Selenium and Vitamin E

Both selenium and vitamin E function as biological antioxidants that protect cell membranes against damage from reactive oxygen species (free radicals) generated during normal cellular metabolism. These nutrients have complementary but distinct mechanisms of action.