A cows hoof is cloven, or divided, into two approximately equal parts, usually called claws. The hoof is covered and strengthened with a thick and horny keratin covering, which is made up of four layers: the stratum externum, the stratum medium, the stratum internum, and the dermis parietis. The stratum externum and the stratum medium are difficult to distinguish, the stratum externum is thin and the stratum medium is what makes up the bulk of the hoof wall. The different parts of the horn include:

• Wall horn: This is the equivalent to our fingernail and is by far the strongest horn and most important for bearing weight.
• Sole horn: The equivalent to the footpad on a dog or cat.
• White line: The junction between the wall horn and sole horn, made up of weaker horn.
• Pedal bone: Equivalent to the bone at the end of our fingertips, it is the main bone in the hoof (triangular in shape).
• Laminar corium (quick): Important tissue supporting the pedal bone within the hoof wall (the ‘laminae’).

Hoof horn grows at about 5mm/month, and the impact of damage to the quick around calving time takes about 2-3 months to manifest itself on the sole surface as either sole bruising or an ulcer.