How To Prevent Founder in Horses

By Dr Duncan Houston

Founder prevention starts before your horse is lame. The real goal is to control the risk factors quietly building in the background: insulin dysregulation, excess body condition, high sugar and starch intake, unmanaged pasture access, poor hoof monitoring, and delayed action when early foot pain appears.

Laminitis is one of the most painful and expensive conditions horse owners face. Founder is often used to describe severe or chronic laminitis where the coffin bone rotates or sinks within the hoof. By the time that happens, prevention has already failed.

The good news is that many modern founder cases are preventable, especially those linked to equine metabolic syndrome, insulin dysregulation, pasture overload, and PPID, also known as Cushing’s disease. The key is not waiting until the horse is “walking on eggshells”. The key is identifying the horse at risk and managing them before the feet start screaming.

Quick Answer

To prevent founder in horses, focus on controlling insulin, body weight, pasture access, sugar and starch intake, and hoof health. Horses at higher risk, especially easy keepers, ponies, overweight horses, horses with a cresty neck, previous laminitis, EMS, insulin dysregulation, or PPID, should be managed with low NSC forage, restricted grazing, regular insulin testing, safe exercise when sound, and consistent farrier care. Laminitis signs such as heat in the feet, increased digital pulses, shifting weight, reluctance to move, or a sawhorse stance should be treated as urgent. (IDPPID)

What Is Founder in Horses?

Laminitis is inflammation and failure of the laminae inside the hoof. These laminae act like tiny interlocking attachments that help secure the coffin bone to the hoof wall.

When the laminae become damaged, the bond between the hoof wall and coffin bone weakens. In severe cases, the coffin bone can rotate, sink downward, or even penetrate the sole. This is the stage many owners refer to as founder. AAEP notes that laminitis and founder are often used interchangeably, although founder usually refers to a more chronic condition associated with coffin bone rotation. (Professional Farriers)

In simple terms:

The clinical point is simple: do not wait for “founder” before taking action. Early laminitis is already an emergency.

Why Founder Prevention Matters

Laminitis is not just a hoof disease. In many horses, the hoof pain is the visible result of a whole body metabolic problem.

Modern laminitis prevention is strongly focused on insulin dysregulation. The Equine Endocrinology Group describes equine metabolic syndrome as a collection of risk factors strongly associated with hyperinsulinemia associated laminitis, with insulin dysregulation as a consistent feature. (IDPPID)

This matters because some horses can have lamellar damage developing before the owner notices obvious lameness. Hyperinsulinemia associated laminitis can begin insidiously, with sustained high insulin damaging the digital lamellae before classic painful signs become obvious. (IDPPID)

That is the uncomfortable part. Your horse does not need to look dramatically lame for the risk to be real.

Which Horses Are Most at Risk of Founder?

Some horses need far stricter prevention than others.

MSD notes that EMS horses are often obese or overconditioned with a cresty neck, but regional fat deposition can occur even without generalized obesity. Importantly, obesity alone is not enough to diagnose EMS, and lack of obesity does not exclude insulin dysregulation. (MSD Veterinary Manual)

That last point matters. Thin horses can still have metabolic risk. Chubby horses are obvious. The sneaky ones are the “not that fat” horses with high insulin and subtle hoof changes.

The EMS and Insulin Connection

Equine metabolic syndrome is not just “being fat”.

The central issue is insulin dysregulation. This may include high resting insulin, an exaggerated insulin response after sugar or starch intake, or tissue insulin resistance. When insulin stays too high for too long in susceptible horses, laminitis risk rises sharply. (IDPPID)

In practice, EMS often looks like:

The mistake owners often make is thinking founder prevention starts when the horse is lame. It starts when the horse is still sound but metabolically risky.

How Do Vets Test for Insulin Dysregulation?

Testing matters because you cannot reliably diagnose insulin dysregulation just by looking at the horse.

A vet may recommend:

MSD notes that a single insulin result can be useful as a screening test, but a low result does not fully exclude insulin dysregulation. Dynamic testing such as an oral sugar test or oral glucose test may be needed when suspicion remains. (MSD Veterinary Manual)

For older horses, PPID testing matters too. The 2025 Equine Endocrinology Group PPID recommendations state that PPID is often accompanied by insulin dysregulation and that insulin dynamics should be assessed alongside PPID testing. They also list pergolide mesylate, dietary management, and general wellness care as the mainstay of PPID treatment. (Squarespace)

Severity Framework: How Worried Should You Be?

A sound horse with risk factors is a management case. A sore horse with laminitis signs is an emergency.

How To Feed a Horse To Prevent Founder

Diet is the foundation. Not supplements. Not wishful thinking. Not “he only gets a tiny scoop” when the tiny scoop is basically a sugar party in a bucket.

For horses with EMS or founder risk, MSD states that diet is the most important element of management and that, for EMS patients, grazing, grains, and treats should be eliminated initially. It also recommends hay that is low in nonstructural carbohydrates, ideally determined by feed analysis. (MSD Veterinary Manual)

Feed low NSC forage

NSC stands for nonstructural carbohydrates. This includes sugars, starches, and fructans.

For high risk horses, hay should ideally test below 10 percent NSC. UC Davis also states that feed analysis is important because hay varies widely, and ideally NSC should be less than 10 percent of dry matter for horses with EMS. (Center for Equine Health)

Practical feeding rules:

Feed the right amount, not just “less”

For overweight horses, UC Davis suggests initially feeding forage at 1.5 percent of the horse’s ideal body weight per day, with possible reduction after 30 days if necessary, under veterinary guidance. Sudden severe feed restriction should be avoided because it may worsen metabolic problems. (Center for Equine Health)

That means founder prevention is not starvation. Starving an overweight horse is not clever. It is just creating a new problem while trying to solve the old one.

Should you soak hay?

Soaking hay can reduce water soluble carbohydrates, but the result is variable. UC Davis notes that soaking may lower water soluble carbohydrate concentrations, but it is not a reliable way to guarantee a low NSC forage. (Center for Equine Health)

Use soaking as a tool, not a magic spell.

How To Manage Pasture Access

Pasture is one of the biggest founder traps because it looks natural.

Grass can still be dangerous for susceptible horses, especially during rapid growth, after stress, after frost, during spring flushes, and in horses with insulin dysregulation. Oregon State University notes that pasture associated laminitis is preventable and results from excess consumption of grass high in nonstructural carbohydrates. (OSU Extension Service)

Practical pasture control includes:

Oregon State recommends low NSC hay, limiting grazing time, using dry lots or grazing muzzles during high NSC pasture periods, and maintaining horses at a body condition score around 4 to 6. It also notes that forage sugar levels are often lowest from 3 a.m. to 10 a.m., but pasture risk still varies with weather, growth stage, season, and plant stress. (OSU Extension Service)

The important rule is this: do not rely on turnout timing alone for a horse that has already foundered.

What Body Condition Should You Aim For?

Most founder prone horses should be kept leaner than owners often think.

A practical target is usually around body condition score 5 out of 9, with some horses best managed closer to 4.5 to 5 depending on breed, age, muscle, workload, and laminitis history.

Monitor:

Weight loss should be gradual. If a horse loses weight too fast, you risk muscle loss, nutritional deficiency, stress, and in some animals, metabolic complications.

Exercise Helps, But Only When the Feet Are Safe

Exercise improves insulin sensitivity, helps reduce fat, supports muscle, and improves metabolic health. But exercise is not appropriate during active laminitis.

UC Davis states that horses with controlled and stable laminitis may benefit from walking if approved by a veterinarian, but exercise is not recommended in active laminitis. MSD also notes that once laminitis has resolved, exercise helps improve insulin sensitivity by building muscle and reducing fat. (Center for Equine Health)

The rule:

Forcing a laminitic horse to walk is not “getting the blood moving”. It is asking damaged laminae to carry load when they are already failing.

Hoof Care Is Founder Prevention

Hoof care is not just treatment after laminitis. It is prevention and early detection.

MSD states that hoof care by a skilled farrier is essential in EMS cases, even without acute laminitis, and that radiography is recommended in at risk cases to detect hoof distortion. It also recommends regular trimming every 4 weeks in high risk cases. (MSD Veterinary Manual)

A founder prevention hoof plan may include:

Your farrier may be the first person to notice subtle hoof changes. Listen to them. A good farrier is basically a hoof detective with tools.

What About Thyroid Supplements?

Thyroid supplementation is sometimes used in selected overweight EMS horses to support weight loss, but it should never replace diet control, insulin testing, or proper laminitis management.

MSD notes that horses with EMS do not suffer from hypothyroidism, but levothyroxine has been used to help weight loss for a limited period until target body condition is reached, followed by weaning. It also states that no drug should be used without proper diet implementation. (MSD Veterinary Manual)

Thyroid medication is not a casual “metabolism booster”. It should be prescribed, monitored, and stopped or tapered when appropriate.

What About Newer Medications for Severe Insulin Problems?

Some horses have dangerously high insulin despite diet restriction, weight management, and pasture control. In these cases, veterinarians may consider medical options.

MSD notes that SGLT2 inhibitors have shown promising results in managing hyperinsulinemia and hyperinsulinemia associated laminitis, although prescribing requires veterinary oversight and depends on local regulations, monitoring, and individual risk. (MSD Veterinary Manual)

The practical message for owners: medications may help selected horses, but no medication cancels out unlimited grass, sugary feed, poor hoof care, or delayed emergency treatment.

When Is Founder an Emergency?

Laminitis should be treated as urgent if there are any signs of foot pain, especially in a high risk horse.

AAEP lists acute laminitis signs including lameness, shifting weight, heat in the feet, increased digital pulse, pain at the toe with hoof testers, reluctant or hesitant gait, and a sawhorse stance. It also states that suspected laminitis should be considered a medical emergency.

Call your vet urgently if you see:

If you suspect laminitis, do not wait to “see if he walks out of it”.

What To Do Right Now If You Suspect Laminitis

1. Call your vet

Tell them your horse may have laminitis. Mention whether there is heat in the feet, increased digital pulses, reluctance to move, recent pasture access, grain access, EMS, PPID, or previous laminitis.

2. Remove grass and sugary feed

Move the horse off pasture if it is safe to do so. Remove grain, sweet feed, molasses treats, and high sugar feeds.

3. Keep movement minimal

Do not force the horse to walk, lunge, or “move through it”. If the horse is painful, movement can worsen damage.

4. Provide deep soft bedding

A deeply bedded stall, yard, or confined area can help support the feet while waiting for veterinary guidance.

5. Do not trim, shoe, or medicate blindly

Hoof support and pain relief matter, but they need a plan. Random trimming, pulling shoes, or using medication without veterinary advice can make the situation worse.

6. Contact your farrier after your vet

Laminitis management is a vet and farrier team sport. Radiographs may be needed to guide trimming and support.

7. Ask about insulin and PPID testing

Once the acute pain is managed, finding the trigger is essential. Otherwise, the next episode is already waiting in the grass.

Common Mistakes Owners Make

Mistake 1: Waiting until the horse is obviously lame

Early laminitis can be subtle. Reluctance to turn, shorter steps, mild footiness, or soreness after pasture should be taken seriously.

Mistake 2: Thinking founder only happens in fat ponies

Ponies and easy keepers are classic, but lean horses can still have insulin dysregulation. Older horses with PPID may also be at risk.

Mistake 3: Feeding “just a little grain”

For a high risk horse, a little grain plus pasture plus treats plus rich hay may be enough to keep insulin too high.

Mistake 4: Trusting hay by appearance

Beautiful hay can be high in sugar. Stemmy hay can still be unsuitable. Test it where possible.

Mistake 5: Starving the horse

Severe feed restriction can create other health problems. Weight loss should be controlled, measured, and nutritionally balanced.

Mistake 6: Exercising during active laminitis

Exercise is useful when the horse is sound and stable. It is harmful when the laminae are actively painful.

Mistake 7: Ignoring the farrier

Chronic hoof rings, long toes, widened white line, or changing hoof shape may tell you the horse has been struggling metabolically for longer than you realised.

Mistake 8: Treating PPID but not testing insulin

PPID treatment matters, but insulin dysregulation is often the laminitis driver. Both may need monitoring.

Founder Prevention Plan for High Risk Horses

Here is the practical prevention checklist.

The best prevention plan is boring. Boring is good. Boring means no 10 p.m. emergency call because a pony met spring grass and lost the negotiation.

What Else Can Cause Laminitis?

Not all laminitis is caused by EMS or pasture.

Important causes and triggers include:

Oregon State lists several laminitis risk factors, including excess pasture carbohydrates, grain overconsumption, obesity, EMS, sepsis, retained placenta, high fever, PPID, stress, supporting limb laminitis, and black walnut shavings. (OSU Extension Service)

This is why “founder prevention” is not only about grass. Grass is a big one, but it is not the only one.

Normal Footiness vs Laminitis Red Flags

If a high risk horse is foot sore, assume laminitis until proven otherwise.

Can Founder Be Prevented Completely?

Not always. Some horses are genetically predisposed, some have severe endocrine disease, and some laminitis triggers are sudden, such as sepsis or supporting limb overload.

But many cases can be prevented, reduced, or caught earlier with the right plan.

The most preventable cases are usually the ones linked to:

Prevention is not about one heroic change. It is about boring consistency.

Will My Horse Be Okay?

Many horses at risk of founder do very well when the problem is caught before severe laminitis develops.

The outlook is better when:

The outlook becomes more guarded if the horse has severe rotation, sinking, repeated episodes, uncontrolled insulin, active PPID, poor hoof support, or delayed treatment.

Related Horse Health Topics To Link Internally

This article fits naturally with:

FAQs About Preventing Founder in Horses

What is the best way to prevent founder in horses?

The best prevention is controlling insulin risk. That means testing at risk horses, feeding low NSC forage, restricting pasture, avoiding grain and sugary treats, maintaining a healthy body condition, exercising only when sound, and keeping up with farrier care.

Can grass cause founder?

Yes. Pasture associated laminitis can occur when susceptible horses consume grass high in nonstructural carbohydrates. The risk is higher in horses with EMS, insulin dysregulation, obesity, PPID, previous laminitis, or heavy pasture access. (OSU Extension Service)

Should a laminitis prone horse have no pasture?

Some high risk horses need zero pasture, at least during active weight loss, unstable insulin control, or after laminitis. Others may tolerate controlled turnout with a muzzle or limited access once insulin is stable. This should be guided by your vet, your horse’s insulin response, and previous laminitis history.

How often should insulin be checked?

It depends on the horse. Testing is commonly done when risk is first identified, after diet or medication changes, after laminitis, and during monitoring of EMS or PPID. Horses with previous laminitis or persistent high insulin may need more regular testing.

Is founder always caused by being overweight?

No. Obesity is common in EMS, but insulin dysregulation can occur in lean horses too. Laminitis can also be triggered by sepsis, retained placenta, grain overload, supporting limb overload, black walnut exposure, PPID, and other systemic problems.

The Bottom Line

Founder prevention is not about waiting until your horse is lame and then panicking.

It is about recognising risk early, especially in easy keepers, ponies, overweight horses, horses with a cresty neck, older horses with PPID, and any horse with previous laminitis. The foundation is simple but strict: test insulin, control pasture, feed low NSC forage, manage weight safely, use exercise only when the feet are stable, and keep farrier care consistent.

The most important rule is this: if your horse shows heat in the feet, increased digital pulses, shifting weight, reluctance to move, or a sawhorse stance, treat it as laminitis until proven otherwise and call your vet immediately.

Prevention is powerful because laminitis is much easier to prevent than repair. Once the coffin bone rotates or sinks, you are no longer managing risk. You are managing damage.

If you are unsure whether your horse is at risk of founder, showing early laminitis signs, or needs insulin, PPID, diet, or hoof care guidance, ASK A VET™ can help you understand what signs matter and when veterinary care is needed.