Horn and Laminae

Cracks

Cracks in the hoof wall can originate either from the sole or the coronary band and can occur in the toe region (toe cracks), quarters (quarter cracks) and heels (heel cracks).

Causes:

  • Dehydrated and brittle hoof
  • Lack of trimming
  • Trauma
  • Poor foot balance

Treatment

Hoof cracks can be prevented in many horses by having regular good foot care, using hoofoils to prevent dryness and feeding supplements containing biotin to promote good quality horn growth. Some cracks become a persistent problem and require stabilizing, usually using a bar shoe. Cracks affecting the coronary band can cause a permanent defect and require continued farriery treatment.

Seedy toe

Seedy toe occurs when there is separation at the white line. The condition does not usually cause lameness unless it is very severe or infection occurs. The two most common causes are mild bouts of laminitis and lack of trimming. A diagnosis can often be made by examination of the foot, however, radiographs can be used to show the full extent of the separation.

Treatment

The condition can usually be managed by a farrier by trimming the hoof wall and using wide webbed, flat shoes. In more severe cases the separated horn and infected material must be removed (dorsal wall resection) under veterinary supervision.

Bruised sole and corns

Bruising is usually caused by trauma to the sole or poorly fitted shoes and is a very common cause of lameness especially in horses with flat feet and thin soles e.g. thoroughbreds. A corn is a bruise between the wall and the bars (seat of corn). The degree of lameness can vary. Horses may become very lame immediately after treading on a stone yet recover after a short while, however, some horses may remain persistently lame. Corns commonly cause horses to be lame when circled especially when the affected foot is on the inside. Areas of bruising can become infected and cause a foot abscess.

Diagnosis

Red areas of bruising can often be identified by examination of the foot, however, this is not always the case especially if the horse does not have white feet. The affected area will show pain over a discrete area when pressure is applied using hoof testers. There may also be heat in the foot and a bounding digital pulse. Testing the hoof with hoof testers to find a painful area.

Treatment

In many cases all that is required removal of the shoe and the paring away of some of the overlying horn to relieve pressure on the bruised area. The horse should be placed on box rest until the lameness has resolved at which point the shoe can be re-applied. An antibiotic spray may be used to help harden the foot. Some, more severe, cases require pain relief e.g. phenylbutazone (‘bute’). If bruising becomes a recurring problem shoes should be seated out and provide plenty of heal support.

Nail bind

Nail bind is direct injury to the sensitive laminae by a shoe nail. Usually horses will become lame a few days after shoeing, although some can be lame immediately. The injured area can sometimes become infected and cause a foot abscess.

Treatment

Sometimes removal of the offending nail is all that is required, however, in many instances the entire shoe is removed.

Foot abscess (pus in the foot)

A foot abscess can be caused by a penetrating wound (nailprick), secondary infection of bruised tissue or as a sequel to a crack in the white line and is the most common cause of lameness in horses. The pain is due to the rigid structure of a horse’s foot. As the infection progresses pressure is built up in the foot as there is nowhere for the abscess to expand. The typical scenario is for a mild lameness to develop quickly, can be hours to days, until the animal is reluctant to bear any weight on the limb.

Diagnosis

The affected foot will have a bounding digital pulse, the presence of heat and pain when pressure is applied with hoof testers. Testing the hoof with hoof testers to find a painful area.

Treatment

Ideally the abscess should be drained from the sole using hoof knives. The foot should then be dressed to keep the area clean and horse kept on box rest until the lameness has resolved and the sole has hardened. Poultices only serve to soften the horn and are best avoided unless the abscess cannot be drained. Tetanus infection can occur as a sequel to a foot abscess, therefore, tetanus antitioxin should be given. To aid in the prevention of foot abscesses horses should have their feet regularly trimmed.

Keratoma

A Keratoma is a rare tumour of the epidermal cells in the laminae. Keratoma’s often produce intermittent infections that drain from the coronary band or white line. At times of infection horses are often markedly lame, this, however gradually resolves as the infection spontaneously clears. A sustained lameness occasionally occurs when the keratoma places pressure on the pedal bone.

Treatment

Treatment is by surgically removing the diseased tissue.

Canker

Canker is an uncommon persistent infection of the frog and sole and is usually caused by prolonged unhygienic or moist conditions.

Treatment

The infected material must be removed, however the chance of recurrence is high and the procedure often requires repeating. Antiseptics and astringents are also used.

Thrush

Thrush is a degenerative condition of the frog causing a foul smelling discharge from the frog clefts. The condition usually develops due to prolonged unhygienic or moist conditions and failure to clean feet regularly.

Treatment

Dry clean bedding and regularly picking out feet are important in both the treatment and prevention of thrush. The affected areas should be trimmed and cleansed with an antiseptic, such as iodine, and then treated with an antiobitic spray.

Puncture wounds to the sole

Penetrating wounds will usually cause an immediate severe lameness and should be fully investigated. Although the penetration may only be superficial, commonly causing an abscess, deeper wounds can damage many other structures. These include the pedal bone, digital cushion, navicular bone, navicular bursa, deep digital flexor tendon, digital sheath or coffin joint. For this reason puncture wounds should be investigated thoroughly. The wound should be probed and, in many cases, radiographs taken to assess which structures are involved. An X-ray of a horse's foot with a probe that had a penetration wound.

Treatment depends on the structures damaged by the penetration.