Quittor in horses is an infection in the collateral cartilage of the hoof, usually caused by a wound that exposes the internal structures of the foot to bacteria. Left untreated, quittor can lead to tissue death, severe pain and other complications.

This condition can be debilitating for affected horses, causing significant lameness and discomfort. Fortunately, quittor is now relatively rare, but it was once commonly seen in working draft horses.

Early detection and prompt veterinary care are critical for the horse’s recovery and long-term health. Surgery is typically required to remove the infected tissue from the hoof.

By understanding the effects of quittor, risk factors and prevention strategies, horse owners and caretakers can safeguard their horses’ hoof health and quality of life.

Quittor in Horses

Quittor is an infection of the collateral cartilage, also known as the ungular cartilage. These are structures located on either side of a horse’s hoof that attach to the coffin bone and provide support and flexibility. [1][2]

Quittor usually develops as a result of trauma or puncture wounds in the area that allows bacteria to enter the internal structures of the foot. [3][4]

Quittor infections typically lead to open draining tracts in the horse’s skin, forming along and just above the coronary band. [5] If the infection is not treated promptly, it can spread to other structures and lead to necrosis (tissue death). [2][6][7]

Other names for quittor include: [5][6][7]

  • Necrosis of the lateral cartilage
  • Necrosis of the medial or lateral collateral cartilage of the distal phalanx
  • Infection of a collateral cartilage
  • Septic chondritis of the collateral cartilages

Hoof Anatomy

It’s helpful for horse owners to familiarize themselves with internal and external hoof structures so they can better understand the pathophysiology of quittor and other conditions of the hoof.

External Hoof

The hoof is the hard outer part of the horse’s foot. It is comprised of: [1][2]

  • Hoof wall: The hard outer surface of the hoof. Similar to nails or claws in other mammals, the hoof is made primarily of a protein called keratin, and grows continuously.
  • Sole: On the underside of the hoof, the area inside the white line (innermost layer of keratin where the soft and hard tissue joins), excluding the frog. The sole is the first layer of soft tissue protecting the inner structures and has a small role in load bearing.
  • Frog: The innermost layer of soft tissue makes an angular structure inside the sole. In addition to protecting the inner structures of the hoof, the frog prevents the hoof from distorting during walking, and is involved in the horse’s awareness of where its feet and legs are relative to each other (proprioception).

The function of the external hoof is to protect the internal structures of the foot. It also helps distribute the shock and weight of the horse’s footfalls. The coronary band is the name for the place where the hoof joins the fleshy part of the foot.

Internal Foot Structures

Inside the hoof, several critical structures work together to ensure proper foot function.

healthy hoof | Mad Barn USAIllustration:

These include: [1][2][8]

  • Coffin bone: Also known as the distal phalanx, provides structural support within the hoof. The coffin bone is the primary load bearing bone in the horse’s foot.
  • Navicular bone: Sits behind the coffin bone and acts as a pulley for the deep digital flexor tendon, which flexes the hoof.
  • Digital cushion: Acts as a shock absorber underneath the coffin bone and helps recirculate blood back up the leg
  • Laminae: Interlocking layers of tissue that secure the coffin bone to the hoof wall
  • Collateral cartilages: Cartilages on either side of the hoof that provide shock absorption and protect internal structures

Collateral Cartilages and Quittor

The collateral cartilages are attached to the coffin bone. These two wing-like structures are located on either side of the bone within the hoof. [1]

Quittor initially develops in the collateral cartilages after a foot wound opens up the internal structures to bacterial infection. [4] Since cartilage does not contain blood vessels, the infection rarely clears on its own. [6]

Without treatment, it can progress to infect the surrounding soft tissue and bones quickly. Immediate veterinary care is required for horses suspected of quittor. [6]

This condition is more likely to occur in the hindlegs. It occurs most often in the back part of the fetlock but is sometimes found in the sides or front of the coronet. In these less common cases, the pain tends to be more severe. [7]

Risk Factors

The incidence of quittor in modern times is quite low. This is because wound care and surgical treatment have advanced significantly in recent decades. A reduced dependence on draft horses has also had an impact on the prevalence of this condition. [3][6]

Risk factors for quittor include: [3][7]

  • Breed: draft horses are more likely to develop quittor than other horses
  • Climate: horses are more likely to develop quittor in the winter due to cold weather
  • Long hair: horses with thicker or longer hair, particularly those that have the hair clipped, are more likely to develop quittor. Horses with thicker hair tend to have more delicate skin. Clipping leaves rough stubble that can inflame the skin, causing it to crack, which makes it more susceptible to infection.

There is no age or sex predisposition to quittor. [#]

Mad About Horses
Join Dr. Chris Mortensen, PhD on an exciting adventure into the story of the horse and learn how we can make the world a better place for all equines.
Apple Podcasts Spotify Youtube
Mad Barn - Equine Nutrition Consultants | Mad Barn USA

Causes

Quittor develops when bacteria enter the internal structures of the horse’s foot through a breach in the hoof.

Breaches can be caused by: [1][6][7]

Quittor can also occur as a secondary complication of other hoof conditions such as laminitis or keratoma. In some cases, there is no apparent injury related to the infection. [7]

Once bacteria enters the interior structures of the foot, it can proliferate and thrive. This leads to inflammation as the immune system targets the infected area. If the infection progresses to the collateral cartilages, it is likely to take hold because cartilage lacks blood vessels, preventing an effective immune response. [1][7]

Inflammation in the hoof also leads to pain and swelling. Swelling compresses blood vessels in the foot, restricting blood supply and worsening symptoms. [1][7]

The horse’s foot is often in contact with mud, manure, urine, and other material where bacteria thrive. This means any wound in the area has a high probability of infection. [3]

In healthy horses, immune cells normally combat infections wherever they arise in the body. These cells are delivered to sites of infection by the bloodstream. Since the hoof has low blood flow and any swelling in the area further reduces circulation, infections that take hold in the foot rarely resolve themselves without medical intervention. [3]

Multiple species of bacteria may be present in a quittor infection, which also makes it more difficult to control without veterinary assistance. [3]

Symptoms

Symptoms of quittor take between 10 days and 6 months to develop from the time of injury. [6] Often the initial wound has healed or appears to be healing when the symptoms of quittor develop. [3]

The characteristic sign of quittor is the appearance of draining tracts in the foot above the coronary band of the horse’s foot. [1]

Draining tracts are small openings or holes on the surface of the skin. The surrounding skin may be red, swollen or warm. [6] These tracts typically discharge smelly pus intermittently. [3]

There may be one or more tract along the coronary band. [6] The draining tracts may appear to heal but reopen spontaneously, indicating the infection is still present. [6]

Affected horses often have moderate to severe lameness as a result of the pain from inflammation in the infected structures. [3]

Swelling may be present throughout the affected limb. Depending on severity, swelling may extend to the: [1][6][7]

  • Coronary region of the foot
  • Fetlock
  • Hock
  • Knee

Other symptoms include: [1][6][7]

  • Sawhorse stance
  • Red skin around the foot
  • Fever
  • Loss of appetite
  • Pus or bloody pus leaking from tracts or underside of the hoof
  • Ulceration and sloughing off of dead skin

Drainage tracts may take months to clear, even with treatment. [6]

Severity

The severity of quittor depends on how deeply the infection penetrates the foot and which internal structures are involved. In mild cases, only one or two drainage tracts develop, and the infection is limited to the cartilage. [7]

In more severe cases, the connective tissues and tendons become infected. [7] Cases where the laminae or surrounding bone tissue are also infected are considered very serious and require aggressive medical intervention. [7]

In severe cases, synovitis (inflammation of the membrane surrounding the joints), periostitis (inflammation of the connective tissue that envelops the bones) or arthritis may develop. [7]

In the most severe cases, the horse develops septic arthritis and must be euthanized. [6]

Severity also depends on where in the foot the infection develops. It is more likely to develop in the heel of the fetlock. When it develops on the sides or front of the coronet, it is likely to be more painful to the horse. [7]

Diagnosis and Treatment

Horses showing signs of quittor require immediate veterinary care. Prompt treatment provides the best chance of the horse making a full recovery. [6]

Diagnosis is based on physical examination and confirmed with MRI and X-rays. [1]

Treatment may be conservative, using only medication, or surgical. There is some evidence that conservative treatment is typically not sufficient to return the horse to soundness. [6]

Conservative treatment includes: [6]

  • Soaking the foot in antiseptic solutions
  • Injecting the tract with enzyme preparations
  • Wound care
  • Antibiotics

In cases where surgery is necessary, the following steps are taken: [6][9]

  1. The hoof is trimmed, rasped and scrubbed
  2. The foot is wrapped for 12 hours in an antiseptic-soaked bandage
  3. The horse is placed under general anesthesia, and an incision is made in the skin around the infected hoof
  4. Necrotic (dead) tissue is scraped away or removed with biological agents
  5. The wound is packed with antiseptic bandages and closed with stitches

After surgery, the antiseptic bandages must be changed every day or two until the cornified layer regrows. [3] If necessary, a cast is placed on the food instead of a bandage. [9]

Robust and diligent wound care is essential for recovery from quittor. Assistance from a veterinarian or a veterinary technician may be required. Some horses may need to stay in hospital after surgery, especially during the initial phase of recovery.

In some cases, a hole is made in the hoof wall to allow drainage of fluids and pus. [3] Horses that have undergone surgery to treat quittor, especially when the hoof wall has been opened, often require special shoeing during recovery. [5]

Prognosis

Horses with quittor typically survive the condition. If treatment is successful in controlling the infection before there is permanent damage to surrounding structures, the horse is expected to be sound upon recovery. Typically, this means they will be able to return to their previous level of performance. [3][9]

In some cases, particularly where the infection has gone deeper or where treatment has been delayed, the horse may remain lame even if the infection is clear. [3][9]

If the joint itself is affected either by the infection or as a complication after surgery, the prognosis for a return to full mobility is poor. [3][9] If septic arthritis develops in the foot, the prognosis is poor. [3][9]

Prevention

Preventing quittor is possible with careful attention to the horse’s feet and prompt first aid to any wounds in the area. Horses should be checked for wounds on the lower limbs on a regular basis, especially after exercise. [9]

First aid for horses with wounds on their feet includes: [9]

  • Stopping profuse bleeding by applying a tourniquet or pressure bandage
  • Icing the area
  • Applying topical antibiotics
  • Stabilizing the foot

Whenever a horse is treated for a penetrating wound, a tetanus shot must be administered by a veterinarian. [9]

Always consult a veterinarian if a new occurrence of lameness has developed in your horse. It’s best to check with a veterinarian before attempting to administer NSAIDs, other pain medications, or antibiotics.

 

Summary

Quittor is an infection of the collateral cartilage in the horse’s foot. The characteristic symptom is oozing, painful, open drainage tracts above the coronary band.

  • Without prompt veterinary care, the infection can spread to other structures and tissues in the hoof and result in permanent, life-limiting lameness.
  • Quittor is caused by bacteria invading the foot through a breach in the skin or hoof.
  • The severity of the condition depends on how deep the infection goes into the structures of the hoof.
  • Treatment is usually surgical removal of dead tissue and clearing out of the drainage tracts, followed by aggressive antibiotic therapy.
  • Prognosis is good if treatment is successful; many horses return to previous levels of performance.

Is Your Horse's Diet Missing Anything?

Identify gaps in your horse's nutrition program to optimize their well-being.

References

  1. Baxter, G. M., Ed., Adams and Stashak’s Lameness in Horses. Seventh edition. Wiley-Blackwell, Hoboken, NJ. 2020.
  2. Blankenship, M. et al., The Equine Hoof and the Problems It Faces. Horsemen’s Update. Grayson Jockey Club Research Foundation. 2007.
  3. Redding, R. and O’Grady, S. E., Septic Diseases Associated with the Hoof Complex: Abscesses, Puncture Wounds, and Infection of the Lateral CartilageVet. Clinics of North America: Equine Practice. 2012.
  4. Quittor in Horses – Musculoskeletal System. Merck. 2015.
  5. Milner, P. and Hughes, I., Remedial Farriery Part 3: The Role of Farriery in the Surgical Management of Quittor in the Horse. UK Vet Companion Animal. 2012.
  6. Honnas, C. et al., Necrosis of the Collateral Cartilage of the Distal Phalanx in Horses: 16 Cases (1970-1985). Journal of the American Medical Association. 1988.
  7. Williams, C., Quittor or Quitter. The Journal of Comparative Medicine and Veterinary Archives. 1892.
  8. Bras, R. J. and Redden, R., Understanding the Basic Principles of Podiatry. Veterinary Clinics of North America: Equine Practice. 2018. View Summary
  9. Burba, D. J., Traumatic Foot Injuries in Horses: Surgical Management. Compendium. 2013.