Iron

Sources

Most concentrates and forages already contain more iron than horses need, without ill effects ^[1]. Adult horses absorb an estimated 15% or less of dietary iron ^[1].

Deficiency

Only horses with chronic blood loss, for example from intestinal or tick parasites, are considered at risk of iron deficiency. Anaemia on its own is not a sufficient reason to supplement iron ^[1].

Excess

Excess iron can interfere with copper and cause anaemia ^[1]. Newborn foals absorb iron more efficiently and are at particular risk: excess ferrous fumarate has caused deaths in newborn foals ^[1].

See also copper, mineral ratios.