Selenium deficiency causes white muscle disease in calves and lambs, reproductive failure, and immune dysfunction in cattle. Systematic supplementation in deficient areas prevents significant animal suffering.
Selenium deficiency causes significant animal suffering that is entirely preventable with appropriate supplementation in deficient regions. White muscle disease in calves and lambs is a painful condition - affected young animals cannot rise or move normally, cannot reach the udder for nutrition, and deteriorate rapidly. The welfare harm extends from individual clinical cases to subclinical effects on the whole herd: impaired immunity, reproductive failure, and generally reduced vitality. The challenge is identifying deficiency before clinical disease occurs, as soil and herbage testing provides early warning that allows preventive supplementation. The narrow therapeutic margin of selenium means over-supplementation causes selenium toxicosis (alkali disease) - a condition with its own welfare harms. Precision in supplementation type, dose, and frequency is important, requiring veterinary or nutritional guidance.