Changes

*Enteroliths, stones consisting of magnesium ammonium phosphate around a central nidus (often a metallic foreign body) occur mostly in horses.  Typically, they lodge at the pelvic flexure or the transverse colon and affect horses greater than 4 years of age.   

*Enteroliths, stones consisting of magnesium ammonium phosphate around a central nidus (often a metallic foreign body) occur mostly in horses.  Typically, they lodge at the pelvic flexure or the transverse colon and affect horses greater than 4 years of age.   

====== Impaction ======

====== Impaction ======

Impacted ingesta/faeces within the intestines can occur in all species though it is especially common in horses.  Predisposing factors in horses include poor dentition, a high roughage diet, and general debility.

Impaction of the colon can occur in all species.  In the dog and cat, dehydrated faecal material is the main cause of impaction whereas in the horse, faeces, digesta, sand, or fibrous material can all contribute.  In horses, predisposing factors include poor dentition, water deprivation, a high roughage diet and general debility. Antihelminthic administration or large parasite burdens can also lead to impaction.

*Commonly occurs in the equine colon although impaction due to fibrous ingesta can occur in the ileum.

*Can occur following antihelminthic administration, especially in horses.

====== Extrinsic ======

====== Extrinsic ======