Learning Centre - White Line Disease
DESCRIPTION: There are two types of white line disease. First, separation from the hoof wall from the underlying laminae at the white line, often starts as a result of hoof wall stress due to poor foot conformation or trimming (eg, long toe, underrun heels) and can start at the toes, quarters, or heel. This is termed Seedy Toe. This results in a cavity that can fill with crumbling material, compromising the integrity of the hoof wall, and allowing subsequent opportunity for anaerobic, pathogenic bacteria and fungi to infiltrate these fissures in the hoof wall. Lameness may be present in severe cases, in which loss of support of the distal phalanx results in displacement similar to that seen in laminitis.
Secondly, white line disease can occur when there is compromised integrity of the white line, and infection occurs, which can be due to approximately 41 different microbes, as reported by Cornell University.
TREATMENT: initially the hoof will need to be trimmed to remove the damaged (crumbly) hoof wall, taking care not to damage the sole or the laminae, to allow light and air into the area. The diagnostic evaluation includes a thorough physical examination and radiographs to assess the extent of separation of the hoof wall and any displacement of the distal phalanx. For treatment, corrective trimming is critical to remove abnormal stresses on the hoof wall. Next is removal of the entire extent of the separated hoof wall to the point that firm, healthy adhesion of the hoof wall to the underlying laminae is required. Topical treatment with tincture of iodine is commonly performed daily for at least a week. Additionally, commercial equine foot formulations that produce chlorine dioxide can also be used. Corrective shoeing is critical to provide adequate support to the remaining foot, while removing stress from the affected regions; a heart bar or egg bar shoe in combination with a resilient putty in the caudal two-thirds of the sole (to provide distal phalanx support) may be necessary if displacement of the distal phalanx is a concern.
Treatment with a very powerful formulation such as MicroMed for Horses, with over 80 different strains of microbes to re-establish beneficial bacteria, and fungi is recommended. This can also offset any further deterioration in the hoof, leading to secondary or recurring infection.