These are stone-like objects which form in the hindgut. Debris such as small grains of sand or grit, pieces of wood or metal, become coated with mineral deposits and can grow to several cm in size. They impede gut function and can in extremis, be fatal, unless surgically removed. Horses on heavily grazed sandy or stony soil are particularly at risk. Diagnosis may require x-rays.
The formation of enteroliths can be avoided by feeding psyllium husk or other fibrous gut regulator (e.g. bran). Periodic use – at say monthly intervals – is particularly advised for horses on heavily grazed sandy soil. Droppings should be checked for foreign bodies for several days after feeding.
This type of material can be used to maintain firm droppings.