An infection of the soft tissues underneath the hoof capsule resulting in the formation of pus. As the formation of pus results in a significant build-up of pressure underneath the hoof capsule, this is an extremely painful condition that can cause non-weightbearing lameness. The colour of the pus can give some indication of the depth of the abscess: superficial abscesses involving predominantly keratinised cells produce dark pus, if deeper structures are involved (corium, subcutis, periosteum or even bone), the pus is pale yellow/grey/pink in colour.