A corkscrew claw is twisted throughout its length in a configuration that displaces the abaxial wall by up to 360°. One or both lateral hind claws may be affected in cows >4 yr old. Although corkscrew claws are rarely seen in bulls, many believe there is a heritable component.
Bone molding is seen in the distal phalanx, but it is not known whether this is a matter of cause or effect. Periarticular exostoses develop around the distal interphalangeal joint, possibly resulting from strain of the distal abaxial collateral ligament. Pressure from the exostosis on the dermis of the wall probably accounts for the excessive growth of the abaxial wall.
Correctly trimming a corkscrew claw requires much skill. The horn formation is extremely hard and difficult to cut. The abnormally narrow shape of the distal phalanx makes it difficult to pare the claw without causing bleeding at the toe. The strategy is to shorten the claw as much as possible without causing bleeding. Next, the horn wall that is displaced beneath the claw is cut away. Then, so far as is possible, the horn is shaped to approximate normal. Trimming helps the animal get around for a while but does not “cure” the condition. Affected animals should ultimately be culled.
Last full review/revision September 2015 by Paul R. Greenough, FRCVS