This is an infection within the horses hoof. It occurs when a foreign object penetrates the white line, sole or through a crack in the hoof wall.
Infections within the hoof often have no way of releasing themselves and so when the infection forms into puss it collects to form into an abscess, it is only through your farrier or vet hoof testing or paring away that the infection will be able to release itself, if left unaided the infection will travel upwards to the coronet band at the top of the hoof wall and form an abscess there.
Horses at risk
Both shod and unshod horses are at risk from abscesses, this risk is increased during wet weather when the horses hooves become a little softer and more susceptible. Horses with bruised soles are also at risk.
Helping to minimize the risk
Regular shoeing and monitoring of the feet and soundness are essential, any lameness should immediately be looked into.
Signs of a foot abscess