What Fluoride Does
Fluoride is a trace element that incorporates into tooth enamel and bone, making them harder and more resistant to decay. However, horses have no established dietary requirement for fluoride, and it is far more relevant as a potential toxin than as a beneficial nutrient. Chronic fluoride exposure from contaminated water, industrial pollution, or rock phosphate mineral supplements can cause fluorosis — a progressive and irreversible condition that damages teeth and bones. Horses are more sensitive to fluoride toxicity than cattle.
How Much?
There is no recommended fluoride intake for horses. Water fluoride levels below 2 parts per million are generally safe, while levels above 5 ppm can cause problems over time. Avoid mineral supplements derived from unprocessed rock phosphate, as these can contain high fluoride levels. Feed-grade mineral supplements are processed to remove excess fluoride. If your water source is near industrial facilities or volcanic regions, consider having it tested.
Signs of Deficiency
There is no recognized fluoride deficiency syndrome in horses. Horses maintain perfectly healthy teeth and bones without any supplemental fluoride.
Signs of Excess
Dental fluorosis causes mottled, pitted, and discolored teeth with excessive wear. Skeletal fluorosis causes bony growths (exostoses), lameness, stiffness, and joint pain. Chronic fluorosis from contaminated water or feed can develop over months to years. Teeth are the first structures affected, followed by bone changes in severe cases.
