A gait abnormality where the hoof of a limb in the protraction phase strikes the medial side of the contralateral limb in the stance phase. The point of contact can be anywhere between the coronary band and the carpus (knee) in the forelimb or proximal cannon in the hindlimb.The injury caused by this type of interference ranges from patches of roughened hair to open wounds. The regions of the  hoof responsible for the interference include toe, quarter and heel.