Injuries & Diseases of the Hoof V: Seedy Toe and Corns
Seedy Toe or White Line Disease is necrosis of the sensitive laminae of the hoof, while the term ‘corns’ refers to inflammation of the area between the wall and the bars of the foot caused through improper shoeing.
Seedy Toe or White Line Disease
Seedy Toe or White Line Disease is necrosis of the sensitive laminae, usually of the anterior wall of the hoof, but it may affect all distal areas of the laminae of the hoof, extending proximally towards the coronary band. Cracks in the white line leading to infection and chronic laminitis with separation of the laminae in the area of the white line (usually at the toe), will cause this condition. Anaerobic fungi have been incriminated in some cases.
Clinical signs and diagnosis of Seedy Toe
Mild or sometimes moderate lameness is usual but not invariable
Examination of the foot will identify a chalky, crumbly white line region, which can be easily gouged out with a foot knife
The adjacent hoof wall has a hollow behind it into which grit and other foreign matter is forced
Occasionally overt sepsis is present with a discharging tract at the coronary band proximal to the region affected
Diagnosis is confirmed by these characteristic clinical features
Lateral radiography clearly shows the air and foreign matter wedged into the area between the wall and the pedal bone.
Treatment of Seedy Toe
Small areas of seedy toe can be pared back to healthy tissue with a hoof knife
If the defect is spotlessly clean the defect can be packed with synthetic filler
If not clean, the cavity is packed tightly with a swab soaked in povidone-iodine or Metronidazole and replaced daily
More severe cases will need to have the wall over the seedy portion completely removed and a small area of wall removed back to sound laminar tissue
The defect should not be filled permanently until all risk of haemorrhage is past and the area is certainly clean and infection free
Extensive defects (some are very wide and as high as the coronet) should be extensively debrided after a shoe with supportive side clips has been fitted to the foot to stabilize the distal margin. The shoe is then removed and the defects are debrided
Once all necrotic and infected tissue has been removed, the defect can be filled with synthetic acrylic filler. The shoe is then reset and the horse rested in a stable with only light walking for 2 weeks
The shoe should be regularly reset every 4 weeks at least and a close check kept on the repair patch to ensure that it remains firm and uninfected.
Corns
The term ‘corns’ refers to inflammation of the area between the wall and the bars of the foot known as the ‘seat of corn’. This is caused through improper shoeing. The heels of the shoe lie inside the wall and therefore cause excessive pressure on the seat of corn. It can also occur when the heels are allowed to drop by poor shoeing techniques, causing tearing of the laminae within the hoof due to the heel being unsupported by the shoe.
Clinical signs and diagnosis of Corns
Acute lameness developing in a horse with poorly fitted shoes or overgrown long toes
Warm or hot bulb of heel and a painful focus detectable at the seat of corn with hoof testers
A focal red or black bruised area, blood-streaked horn or even pus and under running of the heel may be found when the shoe is removed and the foot is pared back
A very small black focus may be all that can be seen at first glance
Careful examination of the hoof wall at the heels may reveal a curled-under wall, which causes pressure on the seat of corn and lamina problems with the urgent need for corrective farriery
Diagnosis is confirmed by the clinical signs and examination of the seat of the corn. A palmar digital nerve block removes the lameness.
Treatment of Corns
Remove bruised solar tissue and, if infected, open and drain the region
Leave shoes off until the area has healed or re-shoe with either a leather or polypropylene pad under the shoe
The defect should be packed with an antiseptic-soaked cotton wool plug
Antibiotics (such as penicillin) are often useful once the tract is draining freely, and the tetanus status is very important for infections of this type
Where horses have thin-walled feet, leading to the heel wall turning under, bar shoes can be used to prevent further bruising. It is essential to make sure shoes are fitted properly to prevent shoe pressure on the white line or on the seat of the corn
The heel is often cut down to sound tissue and the horse shod with raised, graduated heels to balance the foot and regain correct alignment
Plastic heel wedges are often used to retain foot level and balance but these frequently apply even more pressure to the heels and may actually aggravate the problem
Make sure there is sufficient heel on the shoe to support the posterior heels of the foot – consider the use of heart bar shoes or egg bar shoes to support underslung heels.
By Dr Reginald R. R. Pascoe AM - Last updated 16 November 2012
