Copper and zinc are two of the most common trace mineral deficiencies around the world and the symptoms often intertwine and overlap so discussing them together just makes sense.
In addition to the levels of these two minerals often being too low in the diet, factors such as high iron intake and high sulfate in water or forage makes the situation even worse by interfering with absorption.
While other deficiencies may not be easily visible, zinc and copper problems often present in ways that are readily seen.
A dead giveaway of copper and zinc deficiency is bleaching of the coat and red ends on black manes and tails. This is typically blamed on sun exposure, which is true, but horses with adequate levels of melanin will not experience these changes.
Melanin is the pigment that gives skin and hair its color. Melanin also protects against UV radiation and chemical damage. Copper (all colors) and zinc in combination with copper (darker colors) are essential for the production of generous amounts of melanin.
Hoof quality also suffers with copper and zinc deficiency. Deficiencies of either copper or zinc have been linked to:
Dramatic improvements in hoof quality are often seen following adequate zinc and copper supplementation.
Only dietary analysis can tell you the precise amounts needed but consider a ballpark figure of 300 mg of copper and 750 mg zinc as the starting point for horses showing outward evidence of deficiency.
Eleanor Kellon, VMD