Hooves

Ungula

Horn capsules of digits III and IV, which together form the cloven hoof. Each has a wall, sole and heel joined by the white line, and grows from the coronary band.

Laterality:: Paired (left and right)

Draft, not yet reviewed by a veterinarian. Content may contain errors. It is published so the community can review it.

View piece alone in 3D

This piece is a schematic shape, not a scan: there is no freely licensed model for this structure yet.

3D model of this piece: "Cow" by Thunk3D (Sketchfab), CC BY 4.0

Overview

Cattle bear weight on two digits per limb, III and IV. Each ends in a claw (ungula), a horn capsule wrapping the distal phalanx; the two claws of a limb form the cloven hoof and are separated by the interdigital space, covered by skin. Digits II and V are reduced to the dewclaws (paraungulae), caudal to the fetlock, which do not bear weight.

Horn capsule

Periople: band of soft horn at the proximal edge, next to the haired skin.
Wall: hard horn forming the dorsal and abaxial surfaces and continuing on the axial surface, towards the interdigital space.
Sole: plate of horn on the ground surface, between the wall and the heel.
Heel (bulb): soft, elastic horn on the palmar or plantar part, with a digital cushion of fatty tissue beneath it that absorbs impact.
White line: junction between the wall and the sole; it is a weak point of the capsule.

Dermis (corium)

Between bone and horn lies the dermis, highly vascular and innervated, which produces and nourishes the horn. At the coronary band its surface is papillary and forms most of the wall, which grows distally. Under the wall it is laminar: its laminae interlock with those of the horn and attach the distal phalanx to the capsule. Under the sole and heel it is papillary again.

Clinical relevance

Lameness is one of the main welfare problems and causes of economic loss in dairy cattle. Most lesions occur in the lateral claw of the pelvic limb, which bears more weight.

Sole ulcer: lesion of the sole where it meets the heel, caused by compression of the corium between bone and horn.
White line disease: separation of the white line that lets dirt and infection in.
Digital dermatitis (Mortellaro disease): lesion of the skin near the heels associated with Treponema spp., painful and contagious; it is controlled with footbaths.
Interdigital phlegmon (foot rot): infection of the interdigital skin and tissue by Fusobacterium necrophorum, with symmetrical swelling and a foul smell.
Laminitis: inflammation of the corium, often subclinical and linked to ruminal acidosis; it produces poor-quality horn that predisposes to sole ulcer and white line disease.
Hoof trimming: regular functional trimming corrects overgrowth and shares weight between the two claws.