Feeding Horses Safely: Avoiding Toxins and Environmental Contaminants

Turning out your horse in a lush pasture with a nearby babbling brook sounds idyllic…to some horse owners. Others, however, ponder the possibility of toxic plants and environmental contaminants their horses are exposed to and the overall impact of such exposure on their overall health.

Many owners are already aware of the dangers horses might encounter during their time on pasture, including blister beetles, tall fescue, botulism, and maple leaves, but there are other feed-related concerns that aren’t as obvious.

“Substantial contamination of the environment continues to occur with toxins and heavy metals leaching into water and soils, possibly turning a horse’s field of dreams into a buffet of pollutants,” noted Kathleen Crandell, Ph.D., a Kentucky Equine Research (KER) nutritionist.

Heavy metals from landfills and industry, such as cadmium (often found in batteries) and lead (from paint, plastics, and metals). These metals trickle into water and soil, are taken up by plants, and later consumed by horses. In addition to being toxic, causing organ damage, and accumulating in the body, ingestion of heavy metals can inhibit the absorption of other micronutrients, such as zinc, which are needed for important biological processes.

“Getting an accurate history on the previous use of your pastures, noting the proximity of any polluting factories, and investigating the origin of any waterways traversing your land will help to determine if soil or water contamination is a concern,” advised Crandell.

Environmental contaminants vary based on geography. With many horses traveling extended distances in today’s world, they can be exposed to new and potentially harmful toxins or heavy metals that they would otherwise never have encountered.

Finally, consider soil testing to help guide the use of fertilizers to optimize the health of your horse’s pasture. “Keeping the pastures at the appropriate pH will minimize the amount of heavy metal uptake by the plants that the horse will be consuming,” adds Crandell.

*Oke, S., and C.W. McIlwraith. 2010. Review of the economic impact of osteoarthritis and oral joint-health supplements in horses. Accessed September 5, 2015.