Serum (clotted blood)
Copper is an essential cofactor for several enzymatic processes involving synthesis of connective tissue, melanin and also antioxidants. Deficiency has been associated with developmental orthopaedic disease. Adult horses require approximately 0.20-0.25 mg/kg bodymass daily (equating to about 10 mg/kg of ration). The value of measuring serum copper as an indicator of total body status has been questioned.