A stone or fragment of glass or metal penetrating almost through the sole will cause pain due to pressure on the corium and, if not removed, will lead to infective coriitis.
If the foreign body penetrates through to the corium, infection is introduced to the dermal level, and an abscess develops. The rapidity of onset and severity of the lameness depends to some extent on the location of the sole penetration. In the apical and subapical region, the lesion is located between the distal phalanx and the nonresilient sole. As the abscess develops, interungular pressure increases rapidly. Thus, the onset of lameness is rapid, and pain is severe. Acute lameness may cause the animal to stand with the foot off the ground or with the toe lightly touching. A differential diagnosis is fracture of the distal phalanx.
In the sub-bulbar region, the corium is located between the digital cushion (a flexible structure) and the soft, resilient horn of the bulb. The onset of lameness is relatively slow, and the pain is significant but not severe. The pus in the abscess tends to spread over a wide area through the fascial plane and to cause separation of the skin-horn junction at the heel. A moist discharge from this area may be the first indication of the lesion. This is referred to as "underrunning of the heel," a condition that can be confused with double sole (see Double Sole in Cattle).
The foreign body should be removed and the track cored out to the corium with a fine-pointed hoof knife. Creating a large hole is inappropriate. Pus is often released under considerable pressure. Antibiotic should be squeezed into the cavity, which closes rapidly. The opening should not be plugged but covered with elastic waterproof material to prevent blockage with mud or manure.
Treatment consists of removing the foreign body if still present. The detached horn should not be stripped off in its entirety. Part of the detached horn may be removed, but the abaxial wall must be left intact to bear weight and spare the exposed, newly forming sole. Bandaging may not be required, but the animal should be housed in a well-strawed area for a few days.