PPID - equine Cushing's syndrome: PPID in horses (Cushing's)

Your older horse starts retaining their winter coat longer. Their back weakens, their belly seems larger and energy during work becomes less predictable. Sometimes you hear that it is simply age, but if hoof problems, more frequent infections or recurrent laminitis develop too, it is time to stop explaining everything as ageing alone.

PPID, formerly known as equine Cushing's syndrome, is not a rare exception. Many owners of senior horses encounter this disease in everyday stable life. The good news is that accurate diagnosis, treatment and sensible nutrition can significantly improve your horse's quality of life. The bad news is simpler. Better feeding alone or simply giving medication is usually insufficient.

This is why PPID in horses needs a comprehensive approach. Signs, test results, seasonal care changes, weight control, muscle condition, laminitis risk and what your horse receives in the manger every day all matter. In practice, owners do best when they stop looking for a single miracle solution and begin following a management plan.

PPID in horses: a silent problem in your stable

Many cases begin with small details rather than a dramatic crisis. Your horse sheds later. They drink more. They struggle to build muscle despite normal work. They start looking old, although until recently they maintained condition. This is why PPID is so easy to miss.

You often see individual signs without connecting them. One problem is attributed to age, another to weather, a third to poorer hay. Yet with hormonal disease, several apparently unrelated changes usually form the picture.

When my warning light comes on

I am particularly alert when an older horse simultaneously:

• sheds less effectively and retains a thicker coat longer,
• loses muscle, particularly along the topline,
• has laminitis episodes or sore feet without an obvious cause,
• develops infections or takes longer to recover,
• changes behaviour during work, becoming more lethargic or less capable.

This does not mean every such horse has PPID. It means it is worth stopping the guesswork and starting diagnostic investigations.

An older horse does not have to look unwell simply because they are ageing. If their condition changes month by month, the cause needs investigating.

PPID can remain a chronic condition for years. What matters most for you is that a well-managed horse with this diagnosis can remain stable, but consistency is essential. The worst approach is waiting until severe laminitis or obvious wasting develops before acting.

What PPID is and why horses develop it

PPID is a hormonal disease of older horses, but it begins in the nervous system. Over time, dopaminergic control of the intermediate part of the pituitary gland, the pars intermedia, weakens. When this inhibitory mechanism stops working properly, the pituitary releases excessive amounts of POMC-derived hormones, including ACTH. This disrupts hormonal regulation throughout the body and gradually affects muscles, immunity, skin, hooves and metabolism.

For you, one point matters most. This is not simply old age. It is a specific disease that can be diagnosed and managed when diagnostic investigation is combined with a daily care plan.

What happens in a horse with PPID

In practice, I see it this way. Hormonal regulation changes first, followed later by the signs visible in the stable. Your horse may still work, eat and look reasonably normal, while their body is already functioning less steadily at a metabolic level.

Excess ACTH and other peptides from the pars intermedia affect the stress response, energy metabolism and immune function, among other things. A horse with PPID therefore copes less well with demands, recovers more slowly and more often develops problems in several areas at once. This is where veterinary diagnosis connects with nutrition. Understanding the disease mechanism makes it easier to choose a ration that does not add problems with insulin, body weight or laminitis.

Why some horses develop it and others do not

Age is the main risk factor. PPID is diagnosed primarily in older and geriatric horses because neurodegenerative changes develop over years. You do not cause this disease through one poor feeding decision or a brief period of less attentive care.

This matters because many owners revisit every feed bag and missed trimming appointment after diagnosis. That is not how this problem works. You can, however, worsen its course by ignoring subtle changes for too long or feeding a ration rich in sugars and starch despite increasing metabolic risk.

Why PPID is diagnosed more often today

The reason is straightforward. Horses live longer, remain in leisure and sporting work longer, and you are more likely to choose treatment for senior horses instead of attributing their problems to age. This is a positive change, but it also places greater demands on daily care.

In practice, a horse over 15 needs a different perspective from a ten-year-old. Regularly assess not only condition and teeth, but also shedding, muscle quality, thirst, hooves and exercise tolerance. If a tendency to deposit fat or a laminitis episode occurs too, the management plan should immediately include hormone testing and feeding adjustments.

A well-managed horse with PPID can remain stable for a long time. There is one condition. Veterinary diagnosis must translate into your daily routine, from giving medication to choosing specific feed, a balancer and supplements supporting metabolism. This determines whether your horse merely has a diagnosis or actually starts feeling better.

Signs of Cushing's syndrome, from typical to subtle

Your horse is 19, eats much as before, yet looks progressively weaker. Their belly grows, their back drops, they still carry a heavier coat after summer and become breathless sooner after brief work. Many owners attribute this to age. In practice, PPID often begins this way.

The most characteristic sign is hirsutism: abnormal shedding and an excessively long, dense coat. Your horse sheds winter hair late, sweats more in summer, tolerates heat less well and needs clipping more often. This is a clear sign, but usually appears only after the disease has been present for some time.

Small changes appear much earlier and are easy to miss when you see your horse daily. Their shape becomes less balanced. Back and hindquarter muscles gradually waste, while the belly looks more pendulous. Some owners respond by increasing hard feed because their horse looks underfed. This is a common mistake with PPID. If insulin resistance or laminitis risk is also increasing, excess starch and sugars worsen the situation rather than rebuilding muscle.

Daily observations most commonly reveal these changes:

• Reduced exercise capacity. Your horse tires sooner, shortens their stride, is less willing to work uphill and recovers less well after exercise.
• Increased thirst and more frequent urination. Bedding is wetter and your horse visits the drinker more often.
• Poorer tissue repair. Rubs, skin problems or inflammation in the mouth persist longer than before.
• Recurrent infections. Skin, sinus, hoof or periodontal problems occur more often.
• Behaviour changes. Your horse may be more apathetic or, conversely, irritable during grooming and saddling simply because they feel uncomfortable.

Laminitis raises the greatest concern. In some horses, it is the first sign, before the typical Cushing's appearance develops. If your horse has sore feet, a shortened stride, reluctance to walk on hard ground or recurrent episodes after richer grass, consider hormonal and insulin-related factors as well as the hooves themselves.

A horse with PPID rarely shows every sign at once. More often, you see a series of small problems that form one clinical picture over months. This is why careful stable observation has real diagnostic value.

In practice, I recommend recording four things, ideally every 2 to 4 weeks:

• Shedding and coat. When shedding starts, how quickly hair is lost, sweating and clipping needs.
• Muscles and body weight. Topline, hindquarters, neck, belly circumference and side and rear photographs in a similar stance.
• Hooves and gait. Sensitivity on hard ground, shorter steps, recurrent abscesses and changes in hoof rings.
• Drinking, energy and work. How much your horse drinks, how they tolerate training and whether they rest longer after exercise.

These notes help far more than a general feeling that your horse has seemed different lately. They help the vet assess the disease course. For you, they provide a basis for daily decisions. This includes feeding, because a horse losing muscle while at risk of laminitis needs a different strategy from a senior without hormonal problems. Feed, balancer and supplement choices must then reflect signs, test results and metabolic tolerance, rather than age alone.

Diagnosing PPID: how to confirm the disease

In practice, it often looks like this: for months, you notice poorer shedding, different movement and quicker fatigue, yet your horse still somehow manages. Then comes the hardest question. Is this PPID, or still ageing, poorer condition or a separate metabolic problem? Testing alongside a clinical examination provides the answer, rather than appearance alone.

Measuring plasma ACTH is the foundation of diagnosis. This is usually the first test we use because it is available and works well to confirm or support a diagnosis. The result alone is insufficient, however. It must be interpreted in the context of signs, season, age and any concurrent features of insulin dysregulation.

Interpreting an ACTH result

An ACTH result is not a number to assess yourself at the tack room table. A horse with obvious signs and a borderline result may need further investigations, while raised ACTH without typical clinical signs requires considered interpretation by the vet. Overinterpretation is especially easy in autumn, when physiological ACTH fluctuations are greater.

Intermediate results cause the most difficulty. Very high values usually fit the clinical picture well. Problems arise when your horse looks suspicious but the result does not yet give a definite answer. In these cases, I do not guess. I revisit the clinical examination and history of signs and plan the next steps.

Why ACTH alone is not always enough

PPID and insulin disorders often occur together, but are not the same thing. This has major practical importance: a horse can have mild hormonal signs yet a high risk of laminitis. That is why insulin should also be assessed when PPID is suspected, particularly after episodes of hoof pain, recurrent laminitis or easy fat deposition despite muscle loss.

If the picture remains unclear, your vet may suggest a TRH stimulation test. This is useful when signs suggest PPID but baseline ACTH gives no certain answer. For you, one point matters most. Sometimes one blood sample is enough; sometimes further investigation is needed to avoid missing the disease or treating without a sound basis.

A good diagnostic outcome does more than identify disease. It also guides daily management, from medication dose to choosing feed and a balancer and controlling sugar access.

This is particularly important for daily care. If tests confirm PPID and also reveal an insulin problem, the feeding plan must be stricter than for PPID alone without metabolic instability. This is where the vet and nutritionist work together. A test result is not paperwork to file away, but the starting point for decisions about feed type, sugar and starch levels, balancer requirements and muscle support in an older horse.

After diagnosis, regular ACTH checks and consistent clinical assessments are needed. Your treating vet sets the frequency according to signs, treatment and stability. Standard monitoring may suffice for one horse, while another needs a quicker response because the first deterioration appears in the hooves rather than the coat.

Medication and comprehensive horse management

Your horse looks quite well in the morning, but by afternoon is standing more cautiously on the front feet, sweating beneath an overlong coat and leaving feed in the manger. With PPID, these small changes are not age. They signal that medication alone is insufficient if daily care does not keep pace with the disease.

After diagnosis is confirmed, pergolide under veterinary supervision forms the basis of treatment. It limits the effects of excessive pituitary activity, but acts gradually. Improvement is expected over weeks, sometimes longer, depending on signs, test results and concurrent insulin resistance or previous laminitis. Never change the dose yourself. In practice, such independent adjustments most often undermine patient stability.

At the start of treatment, observe not only whether your horse looks better, but also appetite, willingness to move, thirst, sweating and coat quality. Some horses temporarily develop reduced appetite or dullness after starting pergolide. This does not always require stopping medication, but always requires contacting your treating vet to agree the next steps.

Good PPID management involves several parallel measures:

• Regular hoof care. A horse with PPID, especially with insulin disorders, needs ongoing farrier involvement and a prompt response to early pain signs.
• Dental checks. An older horse that cannot chew fibre properly loses weight sooner, uses feed less effectively and more easily enters a vicious circle of muscle loss.
• Clipping and temperature regulation support. Abnormal shedding strains the body. Sensible clipping and suitable rugging often markedly improve comfort.
• Prompt treatment of infection and inflammation. Horses with PPID may have reduced immunity. An untreated abscess, skin inflammation or respiratory infection can affect overall condition sooner.
• Ongoing body weight and muscle assessment. Some horses are too fat; others lose weight despite eating well. These are different problems requiring different management.

A common mistake looks like this: the vet prescribes pergolide, you give it reliably, but your horse still receives unsuitable feed, has irregular hoof trimming and nobody responds to gradual muscle loss. This patient may be receiving treatment, but is not well managed.

Another common problem is treating signs without a plan. Clipping alone will not improve hormonal control. Changing feed alone will not replace pergolide in confirmed PPID. Medication alone will not reduce laminitis risk if excess sugars and starch enter the ration daily. This is why I connect clinical decisions with feeding. A test result should translate into a specific stable routine, fibre type, feed form, medication method and monitoring frequency.

I see the best results when one person coordinates the whole plan and everyone involved knows their responsibilities.

In practice, this means clear roles. The vet manages treatment and follow-up checks. You observe daily changes and follow recommendations. The nutritionist formulates a ration supporting metabolism, weight maintenance and hoof health without creating further problems. Only this combination gives your horse a real chance of lasting stability.

The key to success: feeding a horse with PPID

Horses with PPID often come to me after a similar sequence. Medication has started and you follow the dosage, yet your horse keeps losing weight or, conversely, looks too well covered and faces increasing laminitis risk. The problem usually lies in the daily ration rather than the diagnosis itself.

In practice, I begin feeding advice with a simple question: does this horse need less energy, or a safe increase? PPID does not produce one type of patient. One horse is overweight, has a firm neck and a history of laminitis. Another loses topline, chews hay poorly and cannot maintain weight despite a good appetite. Both share the underlying disease but need different feeds, fibre structures and approaches to protein.

When your horse maintains weight or is overweight

The priorities are controlling sugars and starch and providing micronutrients without unnecessary calories. Simply feeding less is insufficient. If your horse mainly eats average-quality hay, deficiencies in amino acids, copper, zinc or biotin can easily arise. This affects muscles, coat and hooves.

For these horses, Spillers Happy Hoof or Spillers Happy Hoof Molasses Free can work well. These fibre-based feeds are intended to be fed in greater volume than a conventional balancer, helping prolong eating time and reduce frantic feeding. Low sugar and starch levels have a specific metabolic benefit here. Glucose and insulin rise more gently after a meal than with cereal-based mixes, helping keep your horse within a safer metabolic range.

If your horse has a good body weight but starts losing muscle, I prefer adding Spillers Lite & Lean Balancer to increasing ordinary hard feed. A balancer supplies concentrated vitamins, minerals and amino acids in a small serving. It is a sensible choice for a horse needing better building materials for topline and hoof horn quality rather than extra calories.

The aim here is simple. Your horse should feel satisfied, be well nourished and remain metabolically steady.

When your horse loses weight and topline

Restricting energy too sharply simply because your horse has PPID is a mistake here. An older patient with muscle loss, poor teeth or reduced feed utilisation needs more nutritional support, but in a form that does not sharply raise glucose and insulin.

In these cases, I often choose Spillers Senior Super Mash. This feed is soaked and easy to eat even with dental problems. Its advantage is energy supplied mainly through readily fermentable fibre and fat rather than large additions of cereals. This makes metabolic sense. The caecal microflora receives material for steadier fermentation, while your horse gets calories needed to maintain condition.

Another practical option is Spillers High Fibre Cubes. These are useful when traditional energy mixes need replacing but your horse still requires hard feed. The cubes can be soaked, making feeding safer for older horses and helping increase water intake.

How I choose the feeding approach

First, I assess three things: body weight, muscle condition and how your horse eats. Only then do I choose a product.

This distinction helps organise decisions but does not replace individual assessment. The same product may work well for one patient and poorly for another if PPID is accompanied by chewing pain, poor hay, dental disease or recurrent hoof inflammation.

What about Equine America supplements?

A supplement only makes sense once the basics are organised. First come hay, sugar and starch control, appropriate feed, pergolide treatment and regular hoof assessment. Only then do I add targeted support.

In practice, for horses with PPID I most often consider Equine America supplements for areas causing real problems: hooves after laminitis, joints in older horses, digestion where feed utilisation is poorer, or immunity in horses with frequent infections. Choose according to the main sign. An all-purpose product usually achieves less than one chosen for a specific aim.

The best results come from combining diagnosis with daily stable routine. Test results should lead to specific manger-side decisions: how much hay, which fibre form, whether feed needs soaking, whether your horse needs a balancer or a safe source of extra energy. This is where the veterinary plan meets nutrition and your horse starts truly benefiting from treatment.

Checks and monitoring: measuring progress

A few weeks have passed since treatment began. Your horse eats more calmly and you feel the coat looks better, but the main question remains: is improvement real or temporary? With PPID, test results, appearance, behaviour, hoof condition and daily coping must all be assessed together.

What to monitor

Good PPID control involves more than one annual test. A consistent, repeatable observation routine provides the most benefit. It makes real improvement easier to distinguish from a brief symptom-free period.

In practice, I primarily assess:

• ACTH, because it shows whether treatment of the underlying disease is having the expected effect,
• insulin and glucose, ideally interpreted together, because they help assess metabolic and laminitis risk,
• triglycerides or a lipid profile, if your horse is losing weight, in poor condition or using feed less effectively,
• BCS and muscle development, particularly along the topline and hindquarters,
• hoof condition, including digital pulse, sensitivity on hard ground and hoof horn quality,
• appetite, thirst, energy levels and shedding rate.

This monitoring only makes sense when recorded. If you note weight or chest circumference, appetite, coat appearance, movement comfort and any hoof sensitivity each week, you usually spot problems sooner than by eye alone.

What improvement looks like day to day

Improvement rarely arrives all at once. More often, a series of small changes together shows your horse moving away from chronic metabolic strain.

The coat starts changing more appropriately with the seasons. Energy becomes steadier throughout the day. Drinking and urination decrease if these signs were present. The topline stops dropping, and a well-designed ration and suitable exercise allow slow muscle rebuilding.

I watch the hooves particularly closely. They often show first whether the plan is truly protecting your horse. A less pronounced digital pulse, reduced sensitivity when turning, more comfortable trimming and no new laminitis episodes mean more than coat improvement alone.

This reveals the difference between treatment and effective management. Pergolide may improve hormonal control, but if your horse still receives too many simple sugars, poor hay, has dental pain or insufficient protein to maintain muscle, practical results will remain incomplete.

When the plan needs adjusting

Continuing muscle loss, persistent shedding problems, recurrent hoof sensitivity, reduced appetite after starting medication or obvious lethargy signal a need for adjustment. Return to the basics and check the whole picture, rather than only the pergolide dose.

Adjustments most often involve one of four things: medication dose, forage quality and quantity, protein and energy balance, or accompanying problems such as dental disease, pain, infection or limited feed intake. In older horses, I particularly often see an apparent failure to respond to treatment that actually results from chewing difficulties and too little readily digestible fibre.

This is why monitoring must combine medicine and nutrition. If your horse loses weight despite stable ACTH, I investigate the ration and oral health. If hormone results worsen and the feet become sensitive after grass, both treatment and grazing rules need reassessment.

The best-managed horse with PPID is not one that achieves a good laboratory result once. It is one whose plan is regularly reviewed and adjusted before another crisis develops.

If you are planning feeding for a horse with PPID and want safe Spillers feeds and Equine America supplements suited to their condition, age and metabolic problems, you can seek product selection advice at VETfactory. For these horses, a ration based on test results, hoof and dental condition and muscle mass works best.