Cracking up

While some hoof cracks are of no concern, others can cause pain and lameness. Here's all you need to know to avoid them, and treat them if they do occur

HOOF cracks, in the wall of the horse’s foot, can range from a cosmetic blemish to a serious cause of lameness and pain. They can run vertically or horizontally (parallel to the coronary band).

A vertical crack that begins at the coronary band is called a sand crack, whereas one that appears to originate from the bottom of the hoof wall is known as a grass crack.

Knowing how the hoof wall grows and how it is structured helps in understanding the significance of hoof cracks.

THE HOOF WALL

THE hoof wall grows downwards from the coronary band, originating from germinative epithelial cells at the coronet. It takes 10 to 12 months for new hoof wall to grow from the coronary band to where the sole meets the ground at the toe – the “solar surface”. At the heel, it takes around three months.

The hoof wall has three layers. A fine outer layer, called the perioplic horn (also known as the stratum externum), encloses the tubular horny layer that forms the substantial part of the hoof wall (the stratum medium).

Beneath this tough outer layer are the laminae (the stratum internum), vital structures that interweave with the sensitive laminae to hold the pedal bone in position.