Copper is an essential cofactor for a number of vital metabolic pathways in the horse’s body; this means that, without copper, certain enzymes are unable to function optimally. Some of the particularly important processes that involve copper are energy production, iron metabolism, connective tissue formation, central nervous system function, and melanin production.
Energy Production—Cells generate energy by creating ATP (adenosine triphosphate, essentially, fuel that powers the body’s systems), and cytochrome c oxidase (an enzyme that requires copper to function) helps generate an electrical gradient which the cells’ “power plants” (the mitochondria) use to create the energy stored in ATP. Therefore, when a horse’s diet is deficient in copper, his ability to generate energy could be reduced, which in turn could negatively impact his performance.
Iron Metabolism—We often think of iron deficiency as being a possible cause of anemia in horses. However, it’s actually likely to be due to a lack of copper, because most equine diets provide significantly more iron than required. On the other hand, copper in forage-based diets is often lacking. Four copper-containing enzymes known as “ferroxidases” oxidize (chemically change when combined with oxygen) ferrous iron to ferric iron, and ferric iron is what’s mobilized from storage to red blood cell formation sites. Therefore, horses consuming copper-deficient diets might lack the copper needed to mobilize iron, resulting in reduced red blood cell formation.
Connective Tissue Formation—Lysyl oxidase is a copper-utilizing enzyme that is responsible for cross-linking of collagen and elastin in connective tissues. Without this cross-linking, the tissues’ strength and flexibility is reduced. Therefore, copper is vital for the integrity of connective tissue as well as the formation of new bone which requires collagen matrix.
Nervous System Function—The central nervous system and brain require copper-utilizing enzymes for normal function. Phospholipids that make up cell walls (include the myelin sheath around nerves) rely on enzymes that need copper for synthesis. And, the dopamine-to-norepinephrine (a neurotransmitter) conversion requires copper-reliant enzymes.« Back to Glossary Index