What condition is defined as an infection of the stratum medium of the hoof?

• A. Thrush
• B. Hoof abscess
• C. Navicular disease
• D. White line disease

Answer: (D)

The stratum medium is the middle layer of the hoof wall, and a disease that specifically targets that tissue is white line disease. This condition involves infection along the white line, the junction where the wall meets the sole, and often leads to weakening or separation of the hoof wall in that area because the internal horn layers (including the stratum medium) are involved. Thrush affects the frog and surrounding sulci, not the wall’s middle layer. A hoof abscess is a pocket of infection inside the hoof capsule, typically in the sole or white line region but not defined by infection of the stratum medium itself. Navicular disease involves the navicular bone and its surrounding structures, not an infection of the hoof wall’s middle layer.