A stanchion bumper is provided for use with a cattle stanchion having a head opening typically defined by a stationary, vertically-oriented stanchion and a pivotal release stanchion which, when tilted in one direction, enlarges the upper part of the opening so that the animal can insert its head through the opening, a closed position where the pivotal stanchion is vertical and defines a head opening through which an animal cannot withdraw its head, and a downed animal position wherein an enlarged lower opening exists so that a downed animal can withdraw its head. The stanchion bumper is positioned below the pivot point of the release stanchion, such that the lower portion of the release stanchion will engage the stanchion bumper when the animal inadvertently moves the release stanchion past the closed position toward the downed animal position.