Mineral deficiencies cause significant health and welfare problems in sheep. Prevention through appropriate supplementation is far more humane than treating established deficiency.
Sheep mineral deficiency causes welfare harm that is often insidious — developing gradually through non-specific signs of ill-thrift before progressing to the more obvious signs of established deficiency. White muscle disease in selenium-deficient lambs is particularly distressing: affected lambs develop muscle weakness and stiffness, often unable to stand and experiencing pain with each attempt to rise. The preventability of these conditions through appropriate supplementation makes the welfare burden ethically significant — these are not unavoidable conditions but management failures. The counterweight is copper toxicity, which causes acute haemolytic crisis and is rapidly fatal — excessive supplementation in a misguided attempt to prevent deficiency can cause its own welfare disaster. Evidence-based supplementation guided by soil and blood testing is the only defensible approach.