Why Too Much Iron Is A Problem

Excessive iron in drinking water is hazardous to horses, says Dr Mac, and could lead to permanent liver damage or death.

- Dr Mac

A recent publication highlighted the serious health consequence for horses drinking water containing excessive iron. After two horses and a donkey in the Netherlands were diagnosed with haemochromatosis and liver disease on the same farm, researchers found similar disease signs in 20 other horses on eight other farms in the same area. The affected horses all showed clinical signs of icterus (jaundice), weight loss, dull hair coat and lethargy.

Blood tests showed liver failure and excessive iron levels. Drinking water from all the farms showed iron levels between 0,74mg/â„“ and 72,5mg/â„“ (the acceptable level for drinking water is at most 0,3mg/â„“).

Nine of the horses were euthanised and necropsy showed small, hardened rusty-brown livers with nodules, as well as iron accumulation in the pancreas, lungs, spleen, brain, kidneys, thyroid and adrenal glands. None of the surviving horses showed improved health despite treatment; the damage was permanent.