The Nerve in Question: Inside the FEI's Veterinary Rules Overhaul

Before a horse competes at an FEI championship, it stands in a designated inspection area while a veterinary delegate presses a thumb into the soft tissue of its lower limb. The technique is palpation -- manual pressure applied to the palmar aspect of the pastern and the digital region of the foot. What the delegate is looking for is a reaction. A flinch, a withdrawal, an ear pinned, a shift of weight. The question the test answers is elemental: can this horse feel its own feet?

If the answer is no -- if sensation is absent or diminished below normal limits, a condition the FEI classifies as hyposensitivity -- the most likely explanation is that the nerve supply to the foot has been surgically severed. In clinical terms, the horse has had a neurectomy. Under the current FEI Veterinary Regulations, a neurectomized horse is not eligible to compete. The rule is unambiguous in intent. It is, by the FEI's own acknowledgement, ambiguous and difficult to enforce.

That tension -- between what the rules mean to say and what they can actually catch -- is at the centre of the most significant revision the FEI's veterinary rulebook has undergone in years. At Session Five of the FEI Sports Forum on 31 March 2026 in Lausanne, the governing body opened a formal consultation on proposals that include mandatory registration of neurectomies, therapeutic use exemptions for a chronic-disease medication, and restrictions on icing before veterinary inspections. The proposals are scheduled for a vote at the FEI General Assembly in Jiangyin, China, from 2 to 5 December 2026.

As the FEI World Championships open in Aachen today -- more than 800 athletes and horses from close to 70 nations across six disciplines, with jumping alone drawing 179 combinations from 55 nations -- every horse on the grounds will be assessed under the current veterinary regulations. By December, those regulations could look fundamentally different. Each of the four principal proposals asks a version of the same question: when is a horse fit to compete?

The nerve

A palmar digital neurectomy is a surgical procedure in which a portion of the nerve supply to the horse's foot is cut or removed. The primary indication is chronic heel pain -- most commonly navicular syndrome, the degenerative condition of the navicular bone and its associated soft-tissue structures that accounts for roughly one-third of all chronic forelimb lameness in horses. Warmbloods, Thoroughbreds, and Quarter Horses are the breeds most frequently affected.

The logic of the procedure is straightforward. If the horse cannot feel its heel, the heel cannot hurt. For horses whose pain has proven refractory to shoeing changes, anti-inflammatory therapies, and joint injections, neurectomy has historically been the last therapeutic option before retirement. In some cases, it returns a horse to soundness that no other intervention could achieve.

The complication profile is not trivial. Neuroma formation -- the growth of a painful mass of nerve tissue at the cut site -- is the most common adverse outcome. More serious but less frequent complications include rupture of the deep digital flexor tendon and, in rare cases, sloughing of the hoof capsule itself. The nerves can and often do regrow, typically within one to two years, at which point lameness returns and the procedure may need to be repeated or the horse retired.

The welfare concern that the FEI's ban is built on is not about the surgery itself. It is about what happens afterward. A horse that cannot feel its foot cannot protect it. It cannot respond to a stone bruise, an abscess developing under the sole, or the early warning of a tendon under strain. In a show jumping horse -- an animal that lands repeatedly from height on its forelimbs, absorbing forces of several times its body weight through the very structures that neurectomy has rendered insensate -- the absence of protective sensation is not a theoretical risk. It is a structural one.

The ban the sport cannot enforce

The FEI's prohibition on competing neurectomized horses is longstanding and, in principle, clear. But the mechanism for enforcing it depends almost entirely on detection at the field of play. Limb sensitivity examinations at FEI events are conducted using palpation -- manual pressure applied to the limb by an examining veterinarian -- supplemented in some cases by thermographic cameras that detect abnormal heat patterns in the skin. When a horse shows diminished response to palpation -- hyposensitivity -- the examining veterinarian reports it, and the horse may be excluded from competition.

The problem is that palpation is a subjective assessment conducted under time constraints, and neurectomy does not always leave a detectable trace. Nerves regrow. Surgical scars fade. The sensitivity threshold below which hyposensitivity is flagged is itself a matter of clinical judgment rather than a fixed quantitative standard. A horse that was nerved two years ago may respond to palpation normally if nerve regrowth has occurred -- even though the procedure, and the structural vulnerabilities it introduced, are part of its medical history. The current system asks the examining veterinarian to detect, in a brief clinical encounter, a surgical procedure that may have been performed years earlier and whose physical evidence may have resolved.

The FEI has characterised the current rule as ambiguous and difficult to enforce. That assessment is, if anything, generous. The ban is the right principle. The enforcement mechanism is not equal to it.

Two proposals, one gap

The revision discussed at the Lausanne Sports Forum puts two alternatives on the table. The first is a system of mandatory registration: every neurectomy would be compulsorily recorded in the horse's FEI passport. The second, positioned as a fallback if the registration proposal does not command a majority at the General Assembly, is an express prohibition of palmar digital neurectomy specifically -- a targeted ban on the procedure that removes sensation from the heel, the variant that the FEI has identified as presenting a major risk to the horse.

The registration model shifts the enforcement burden from detection to disclosure. Instead of asking veterinarians to identify a nerve procedure at the show through clinical examination, it would require that the procedure be declared in the horse's official record at the time it is performed. The passport becomes the instrument of compliance, not the palpation test. For anyone who has watched a veterinary delegate attempt to assess limb sensitivity in a horse that is fractious, agitated by the crowd, or standing on unfamiliar footing, the appeal of a disclosure-based system is immediately apparent.

The fallback -- banning palmar neurectomy specifically while leaving other nerve procedures to be addressed through the registration system or future rules -- acknowledges a clinical reality that the current blanket ban does not. Not all neurectomies carry the same risk profile. A palmar digital neurectomy, which removes sensation from the entire heel, is categorically different in its welfare implications from procedures on more proximal or less structurally critical nerve branches. A targeted prohibition of the highest-risk procedure, paired with passport registration for others, is a more granular approach than the current binary.

Both proposals are defensible. Neither is complete without the other. Passport registration creates accountability -- the procedure is on the record, and any attempt to compete a registered horse in violation of the rules is a documentable offence rather than a clinical judgment call. But it depends on voluntary compliance by the veterinarian performing the procedure and the horse's owner. An undisclosed neurectomy in a jurisdiction with weak veterinary oversight would leave the passport clean and the horse insensate. Field-of-play testing -- the palpation exam the sport already conducts -- remains the only check on that gap. If the revision strengthens registration while weakening testing, it trades one enforcement failure for another.

The medication the horse cannot stop

The second major proposal in the revision concerns a different kind of fitness question. Pituitary pars intermedia dysfunction -- PPID, commonly known as Cushing's disease -- is a neurodegenerative condition of the pituitary gland that primarily affects older horses. Prevalence increases sharply with age: published estimates place it at 15 to 25 percent of horses over 15 years of age, with some studies suggesting higher rates in populations over 20. The average age at diagnosis is 19. The condition is not breed-specific, though it has been documented across all major sport horse breeds, including warmbloods.

The only FDA-approved treatment for PPID in horses is Prascend, a pergolide mesylate tablet manufactured by Boehringer Ingelheim. Pergolide is a dopamine agonist that counteracts the hormonal dysregulation caused by the disease, reducing the excessive release of ACTH, beta-endorphin, and melanocyte-stimulating hormone. For affected horses, it is not an optional supplement. It is a daily medication that manages a progressive, irreversible condition. Without it, clinical signs -- abnormal hair coat, muscle wasting, increased susceptibility to infection, laminitis -- worsen.

Under current FEI rules, pergolide is classified as a prohibited substance. Horses competing at FEI events must withdraw from the medication before competition. The logic is consistent with the FEI's broader clean-sport framework: substances that could influence performance or mask conditions are prohibited in the competition environment. But the practical effect is that a horse with a diagnosed chronic disease must stop its treatment in order to compete -- a requirement that, in welfare terms, asks the horse to get sicker so that the rules can be satisfied.

The United States Equestrian Federation resolved this tension in 2018, when it began allowing therapeutic use exemptions for pergolide at USEF-licensed competitions. Under the domestic TUE system, a veterinarian submits medical records confirming the PPID diagnosis, and the horse is permitted to compete without withdrawing from pergolide. The system has been in place for nearly eight years without reported controversy. The FEI proposal would extend the same framework to international competition, bringing the global standard into alignment with what the largest national federation in show jumping already permits.

The ethical question the proposal raises is genuine, even if the practical answer seems clear. Can a horse that requires daily medication to maintain normal physiological function be considered fit to compete on equal terms? The counter is equally direct: a horse on stable, well-managed pergolide therapy is healthier than the same horse in withdrawal from it. The fitness-to-compete question should not be answered by requiring the horse to demonstrate unfitness first.

The 30-minute rule

The third proposal is narrower in scope but pointed in its implications. Under the proposed amendment, a horse may not be cooled with ice within 30 minutes before a veterinary check or re-inspection.

Ice is a standard therapeutic tool in sport horse management. It reduces inflammation, manages soft-tissue swelling, and is widely used between rounds, after schooling, and in the hours following competition. Its legitimate use is not in question. The concern is timing. Applied in the window immediately before a veterinary inspection, ice can suppress the heat and inflammation that are the visible markers of a limb under stress. A horse with subclinical inflammation in a tendon or a joint may present normally if ice has been used to cool the limb before the veterinarian arrives. The inspection then clears a horse whose limbs, under normal thermal conditions, might have warranted a closer look.

A 30-minute restriction does not prohibit icing. It prohibits timing it to coincide with the inspection. The distinction is the same one that governs medication timing in competition: the substance or therapy is not the problem. The question is whether it is being used to manage a condition or to conceal one.

What the test finds

The revision also proposes changes to the limb sensitivity protocols themselves -- the examination procedures that are the sport's primary tool for detecting both neurectomy and the application of irritants to a horse's legs. Current protocols assess for hyposensitivity -- diminished sensation, which indicates neurectomy -- and hypersensitivity -- exaggerated response, which can indicate sensitising agents applied to make a horse jump higher to avoid touching a pole.

The proposals under discussion include a review of the hyposensitivity threshold -- the level of diminished sensation below which a horse is flagged -- and the removal of the Final Hypersensitivity examination. The specifics of these changes are still in consultation, and the FEI has emphasised that many of the most consequential proposals remain at a conceptual stage. The General Assembly vote in December will determine which make it into the revised regulations.

The limb sensitivity examination is not a perfect instrument. It relies on subjective clinical judgment, it is conducted under the time and logistical pressures of a major competition, and it is assessing a biological system whose normal range of variation is wide. A stoic horse and a neurectomized horse can look the same under palpation. But imperfect is not the same as dispensable. If the passport registration model for neurectomy depends on disclosure, and disclosure depends on good faith, then the palpation test is the only independent verification the sport has at the field of play. The revision should calibrate the test -- refine its thresholds, standardise its application, improve the training of examining veterinarians. It should not diminish it.

The question Aachen asks

The FEI World Championships that open in the Soers today are the sport's most visible international stage. Over the next two weeks, hundreds of horses will be inspected, assessed, palpated, and trotted in hand before the Ground Jury and Veterinary Delegate. Every one of those inspections is conducted under the current veterinary regulations -- the same regulations the FEI has acknowledged need revision.

The neurectomy ban will apply. It will be enforced through palpation. Some horses with nerve procedures may pass. Some horses with naturally stoic temperaments may be held for further examination. The system will work as it always has -- imperfectly, in good faith, with the tools available.

The pergolide prohibition will apply. Horses with PPID that are competing at the international level will have withdrawn from their medication. Some will show no ill effects. Others -- particularly those whose disease is more advanced or whose response to treatment withdrawal is more acute -- will compete in a physiological state that their own veterinarians would not endorse.

Ice will be available. No 30-minute restriction will apply. Whether it is used therapeutically or strategically will be, as it has always been, a matter that happens in the barn and stays there.

The revision heading to Jiangyin is the FEI at its most thoughtful. Passport registration is better enforcement than detection at the field of play alone. The pergolide TUE is a welfare improvement that USEF validated nearly eight years ago. The ice restriction is common sense. But the sport must not weaken the tests it already has in the process of building the systems it needs. Registration creates accountability. Testing creates deterrence. The veterinary regulations revision should strengthen both -- because "fit to compete" is not a question the passport can answer on its own. It is a question the horse answers, every time a thumb presses into its leg and waits for a reaction.