19/02/2026
ALUMINIUM AND THE RISKS TO YOUR HORSE.
Most horse owners have no idea that their horse has been exposed or is exposed to high levels of aluminium and in worse cases aluminium toxicity.
Aluminium is abundant in most Australian soil profiles. It is a toxic metal. It is the level of aluminium that can pose problems for your soil and for your horse. When the level of aluminium is high soil acidity increases and your soil suffers. So when soil pH is below 5 you have poor, acidic soil and high iron. High iron occurs when soil pH drops below 5.5 Many horse owners/agistment properties do not lime their paddocks which increases the risk of aluminium toxicity.
How does this affect my horse you ask? Horses ingest soil due to grazing habits. They pull up roots with soil attached. A horse can ingest approx 1 to 1.5 kgs soil per day which means your horse is getting an unhealthy dose of iron and aluminium. The grass and weeds that grow on this type of soil will also contain aluminium and iron as they uptake whatever nutrients and toxic metals are in the soil.
How common is it for a horse to have high levels of aluminium? Every second horse I test has a level of aluminium. 1 in 5 horses has aluminium toxicity in Australia. In New Zealand 1 in 10 horses has aluminium toxicity.
The usual source of exposure is from grazing on poor, acidic soils and often some bore water contains high levels of aluminium. Some prepacked, premixed feeds contain aluminium as an anticaking agent. Some beet products contain naturally occurring aluminium and of course hay often has a level also which is not shown on a hay test unless you request it.
The symptoms of chronic aluminium exposure not aluminium poisoning which is quite different are usually: kidney and liver stress, dull, rough coat, lowers the uptake of other minerals, affects bone density, interferes with normal immune function, colics and gastrointestinal upset. In humans excess aluminium has been implicated in the onset of Alzheimers disease. As usual, more studies need to be done on the effects of alumniium toxicity in horses.
Aluminium is a toxic metal which means it crosses the placental barrier. So if a pregnant mare has a level of aluminium the foal will absorb it and be born with an aluminium level. It stays in the body until an antagonist removes it and minerals that the alumnium depleted are supplemented.
The only effective solution to aluminium toxicity in your soil is to HTMA your horse first then soil test to confirm that the aluminium is from your place and not the previous property where the horse lived. Then lime your paddocks. The ONLY test available to accurately detect aluminium in your horse is hair mineral analysis the test of choice for toxic metals provided you test in a govt licencsed and accedited laboratory and you use a scientist to interpret the results.
Kerry Marsh BAgrSc
kerrymarsh@htma.com.au
References: Lars Friberg at al. Handbook on the Toxicology of Metals. Elsevier 1986
Jachimowicz-Rogowska K et al. Seasonal Changes in Trace Element Content in the Coat of Hucal horses. Animals 12 (20) 2022
Ramesh C Gupta. Veterinary Toxicology Basic and Clinical Principles 2007
Roger Hall. Soil Essentials: Managing your Farm's Primary Asset CSIRO 2008