Nutritional myopathy (muscle disease from vitamin E or selenium deficiency) causes serious welfare harm in horses. Prevention through appropriate diet is achievable.
Nutritional myopathy welfare is preventable suffering. Horses in winter on hay-only diets without fresh grass access lose their primary vitamin E source, and hay provides only a fraction of fresh grass vitamin E content. The resulting muscle weakness, difficulty swallowing, and pain from muscle damage cause significant suffering that can be entirely avoided through appropriate supplementation. The selenium challenge is different - both deficiency and toxicity cause welfare harm, requiring careful management of supplementation levels based on regional soil selenium content and diet analysis.