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 ======

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.

*Impaction of the colon can occur in all species.   

*In the dog and cat, dehydrated faecal material is the main cause of impaction.

*In the horse, faeces, digesta, sand, or fibrous material can all contribute. 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.

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

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