Crossfiring may result in which condition?

• A. thrush
• B. shoe boils
• C. sidebone
• D. founder

Answer: (B)

Crossfiring happens when the nails in a nailed-on shoe are driven at improper angles, causing them to cross toward the opposite wall and potentially penetrate into sensitive hoof tissues or even the sole. This misdirection creates irritation and allows bacteria to enter, leading to an abscess at the nail track commonly called a shoe boil. The other conditions—thrush, founder, and sidebone—have different causes: thrush is a moist, bacterial/fungal infection of the frog; founder is a laminitic rotation or sinking of the coffin bone; sidebone is ossification of the collateral cartilages. So crossfiring most directly leads to a shoe boil.