Axial Deviation of the Aryepiglottic Folds in Horses

Quick Answer
  • Axial deviation of the aryepiglottic folds is a dynamic upper-airway problem where soft tissue near the larynx collapses inward during inhalation, especially at speed.
  • Many horses look normal at rest. The problem is often found only during exercise endoscopy or high-speed treadmill endoscopy.
  • Common clues are inspiratory noise, reduced stamina, and poor performance during fast work rather than obvious illness in the barn.
  • Treatment options range from monitoring and managing contributing airway issues to transendoscopic laser surgery, depending on severity and your horse's job.
  • When this is the only airway problem, some horses improve with rest and management, but surgery tends to give a higher chance of performance improvement.
Estimated cost: $400–$4,500

What Is Axial Deviation of the Aryepiglottic Folds in Horses?

Axial deviation of the aryepiglottic folds, often shortened to ADAF, is a disorder of the horse's upper airway. The aryepiglottic folds are soft tissue structures near the entrance to the larynx. In affected horses, part of this tissue moves inward during inhalation and narrows the airway when the horse is working hard. That can create abnormal noise and limit airflow.

This is considered a dynamic problem, which means it happens during exercise rather than all the time. A horse may breathe normally in the stall and even have a fairly normal resting endoscopic exam. Because of that, ADAF can be frustrating for pet parents, trainers, and riders who know the horse is not performing right but do not see obvious signs at rest.

ADAF is reported most often in performance horses, especially racehorses, and it may occur by itself or along with other upper-airway problems. In some horses it appears to be secondary to altered airflow from another obstruction. That is one reason a full airway workup matters before making treatment decisions with your vet.

Symptoms of Axial Deviation of the Aryepiglottic Folds in Horses

  • Inspiratory noise during fast work
  • Poor performance at speed
  • Reduced stamina or exercise intolerance
  • Normal breathing at rest
  • Intermittent signs
  • Signs of another airway problem at the same time

ADAF is usually not an emergency if your horse is comfortable at rest, but it does deserve a veterinary workup if exercise noise or poor performance keeps happening. The biggest concern is not usually collapse in the barn. It is missed diagnosis, because several upper-airway disorders can sound similar.

See your vet promptly if your horse develops louder noise, marked exercise intolerance, coughing, trouble swallowing, nasal discharge after work, or any breathing effort at rest. Those signs can point to a different or more serious airway problem.

What Causes Axial Deviation of the Aryepiglottic Folds in Horses?

The exact cause of ADAF is not fully understood. Current equine airway literature describes it as a dynamic collapse of the aryepiglottic folds during inhalation. In some horses, it seems to happen because the tissue itself lacks enough tension. In others, it may develop secondary to abnormal airflow caused by another upper-airway obstruction.

ADAF has been associated with conditions such as rostral displacement of the palatopharyngeal arch, recurrent laryngeal neuropathy, and other dynamic airway abnormalities. It has also been reported after partial arytenoidectomy and in horses with altered laryngeal mechanics. That means your vet may need to look beyond the fold collapse itself and ask what is driving it.

Younger racehorses appear overrepresented in published case series, but no strong breed or sex predisposition was identified in one classic study of 52 racehorses. Because this problem often shows up only during strenuous exercise, work intensity, airflow demands, and head-and-neck position may all influence when signs appear.

How Is Axial Deviation of the Aryepiglottic Folds in Horses Diagnosed?

Diagnosis starts with a history of exercise noise, poor performance, or both, plus a full physical exam and resting upper-airway endoscopy. Resting scope findings may be normal or may show other abnormalities that raise suspicion. Still, resting endoscopy alone often cannot confirm ADAF.

The key test is dynamic endoscopy during exercise. This may be done on a high-speed treadmill or with overground endoscopy while the horse works in a setting that matches its job. Dynamic endoscopy allows your vet to watch the airway at the moment signs occur and determine whether the aryepiglottic folds are collapsing inward during inhalation.

This step matters because ADAF can occur alone or alongside other disorders such as palatal instability, pharyngeal collapse, or laryngeal dysfunction. A correct diagnosis helps your vet match treatment to the actual problem instead of treating noise alone. In many horses, the most useful question is not only "Is ADAF present?" but also "Is it the main cause of this horse's limitation?"

Treatment Options for Axial Deviation of the Aryepiglottic Folds in Horses

Spectrum of Care means you have options. Here are treatment tiers at different price points.

Budget-Conscious Care

$400–$1,200
Best for: Horses with mild signs, uncertain significance of the lesion, financial limits, or cases where your vet suspects the collapse may be secondary to another issue.
  • Resting airway exam and basic endoscopy
  • Short period of rest or training modification
  • Addressing concurrent inflammation or lower-airway disease if your vet finds it
  • Monitoring performance before committing to surgery
Expected outcome: Variable. Some horses improve with rest and management alone, especially if ADAF is mild or not the only factor affecting performance.
Consider: Lower upfront cost, but it may not fully resolve exercise noise or poor performance. If dynamic endoscopy has not been done, the true cause can still be missed.
Most Common

Recommended Standard Treatment

$1,200–$3,000
Best for: Performance horses with confirmed ADAF causing inspiratory noise or reduced performance, especially when the lesion appears to be a primary contributor.
  • Dynamic endoscopy during exercise
  • Complete upper-airway assessment for concurrent disorders
  • Standing transendoscopic laser resection of the axial portion of the aryepiglottic folds when indicated
  • Sedation, local anesthesia, medications, and follow-up recheck
Expected outcome: Good in many appropriately selected cases. Published outcome data suggest better objective improvement after surgery than after rest alone when ADAF is the only upper-airway abnormality.
Consider: Requires specialized equipment and expertise. Recovery time, recheck exams, and the possibility of concurrent airway disease can affect final results.

Advanced / Critical Care

$3,000–$4,500
Best for: High-level athletes, horses with multiple airway problems, repeat poor performance after prior airway surgery, or cases needing a board-certified equine surgeon.
  • Referral-hospital workup with treadmill or overground dynamic endoscopy
  • Surgical correction plus treatment of concurrent upper-airway abnormalities during the same care plan
  • Hospitalization, advanced imaging or repeat endoscopy if needed
  • Specialist follow-up and return-to-work planning
Expected outcome: Depends on whether ADAF is isolated or part of a more complex airway picture. Outcomes are often best when all clinically important lesions are identified and addressed together.
Consider: Highest cost range and more intensive workup. It may uncover multiple contributing problems, which can change the treatment plan and timeline.

Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.

Questions to Ask Your Vet About Axial Deviation of the Aryepiglottic Folds in Horses

Bring these questions to your vet appointment to get the most out of your visit.

  1. Do you think this airway problem is the main reason for my horse's noise or poor performance, or could there be another cause too?
  2. Does my horse need dynamic endoscopy, and would treadmill or overground endoscopy be more useful for this job?
  3. Were any other upper-airway abnormalities seen along with the aryepiglottic fold deviation?
  4. If we start with conservative care, what signs would tell us it is time to move to surgery?
  5. If surgery is recommended, would it likely be done standing with a laser, and what does recovery usually involve?
  6. What is the expected cost range for diagnosis, treatment, and follow-up in my area?
  7. What is the realistic outlook for return to racing, showing, or the level of work my horse does?
  8. Should we also evaluate for lower-airway inflammation or other performance-limiting conditions?

How to Prevent Axial Deviation of the Aryepiglottic Folds in Horses

There is no guaranteed way to prevent ADAF, because the exact cause is still not fully defined and some cases appear related to airway mechanics during intense exercise. Still, early attention to exercise noise and subtle performance decline can help your vet identify problems before a horse spends months training with an unresolved airway issue.

Good preventive care focuses on the whole respiratory system. Keep up with routine exams, discuss any repeated noise during work, and ask your vet whether lower-airway inflammation, pharyngeal disease, or another upper-airway disorder could be contributing. Horses with persistent signs may benefit from earlier dynamic endoscopy rather than repeated trial-and-error changes in training.

For performance horses, it also helps to track exactly when the noise happens, how hard the horse is working, and whether head carriage or discipline seems to matter. Videos from exercise sessions can be useful. While that will not prevent the condition itself, it can shorten the path to an accurate diagnosis and a treatment plan that fits your horse and your goals.

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