An older horse that doesn't shed its winter coat, drinks more than it used to, and loses muscle over the back — that combination often points to Cushing's disease, officially called PPID. It's one of the most common hormonal disorders in older horses and ponies, and at the same time one of the most treatable. This guide explains what happens in the body, which signs deserve serious attention, how the diagnosis works, and what daily management looks like.
What PPID Is
PPID stands for pituitary pars intermedia dysfunction: a condition in which part of the pituitary gland — a small gland at the base of the brain — becomes dysregulated. That gland normally controls the hormone balance. With PPID, the inhibition on part of the gland is lost, so it starts producing too many hormones. That excess affects the whole body: coat shedding, muscle development, fat distribution, immunity, and metabolism.
The condition mainly occurs in older animals, usually from around age fifteen, and just as much in ponies as in horses. PPID develops slowly. Precisely because of that, the first signs are often dismissed as "just old age" — while early intervention makes a real difference.
The Signs at a Glance
The best-known picture is the coat: long, often slightly curly, and a winter coat that doesn't shed in spring, or only sheds halfway. But the coat is usually a late sign. These symptoms can already be present earlier:
| Sign | What You See |
|---|---|
| Coat problems | Long, sometimes curly coat; slow or incomplete shedding; sweating in warm weather |
| Drinking and urinating more | The water bucket empties faster, the stall is wetter than before |
| Muscle loss | The back and croup muscles shrink; the topline sinks in, sometimes with a pot belly |
| Fat deposits | Fat pads in fixed spots, for example above the eyes or on the neck |
| Lethargy | Less energy and willingness to work; the horse looks "aged" |
| Recurring infections | Skin problems, abscesses, or wounds that heal slowly; stubborn worm infections |
| Laminitis | Sensitive movement, a creeping or acute episode — sometimes the very first sign |
That last one deserves particular emphasis: PPID significantly raises the risk of laminitis, and some horses are only tested after an episode. For any older horse with unexplained laminitis, the question of PPID belongs on the table.
Why Early Recognition Pays Off
PPID can't be cured, but it can be managed well — and the earlier you start, the more you preserve. Recognized early, muscle, immunity, and hooves stay in better shape for longer, and you reduce the chance that the first real sign is a laminitis episode. If you wait until the classic picture is complete, muscle mass has often already been lost, and the horse has been walking around with simmering complaints for months or years.
If you're unsure about coat shedding, drinking behavior, or condition in a horse over fifteen, discuss it with your veterinarian. An annual check-up is a good idea for older horses regardless; you can read about that bigger picture in caring for a senior horse.
Diagnosis: Blood Testing by the Veterinarian
The veterinarian makes the diagnosis using blood testing, usually combined with the clinical picture and history. The time of year affects how the result is interpreted, so the veterinarian decides when and how testing happens. In a borderline case, a retest after a few months may be needed. The same blood test is then used to monitor whether treatment is working — expect a check at least once a year.
Daily Management
Once the diagnosis is confirmed, management consists of a fixed set of elements. Lifelong, but easy to fit into a normal stable routine.
- Medication from the veterinarian. Medication exists that suppresses hormone production; the veterinarian prescribes it and adjusts the dose based on blood checks. Most horses improve noticeably: more energy, better coat shedding, less drinking. Giving the medication daily and consistently is the core of the treatment.
- Feeding a low-sugar diet. Many PPID horses are sensitive to sugar and starch, which further raises the laminitis risk. Choose forage with a low sugar content, be cautious with concentrate feed and grass during fast-growing periods, and align the ration with your veterinarian or a feed advisor. If the horse is losing weight instead, supplementing with low-sugar, energy-rich feed is the way to go — weight loss shouldn't become a side effect of the diet.
- Clipping for coat problems. A horse that keeps its winter coat gets uncomfortably hot in summer and sweats heavily. Clipping, potentially several times a year, is a practical solution. More on coat changes and rug policy is in seasonal coat care.
- Extra attention to teeth, hooves, and parasites. Because of the lower immunity, problems take hold more quickly. Keep dental checks and the trimming cycle tight, check wounds and skin extra carefully, and discuss the deworming approach with the veterinarian — fecal egg counts are especially worthwhile for these horses.
- Laminitis prevention. Watch daily for sensitive movement, warm hooves, or a bounding digital pulse, be cautious with turnout on young, fast-growing grass, and call the veterinarian immediately if in doubt. Acting quickly at the start of an episode is the difference between a short episode and lasting damage.
Living with a Cushing's Horse
A PPID diagnosis isn't the end of a horse's working or happy life. With daily medication, suitable feed, and an attentive owner, many horses still have years of quality of life ahead — often including light to normal work, if condition and hooves allow it. The condition mainly demands consistency: the medication every day, the feed reviewed every season, the blood check every year. Once you've got that rhythm down, you'll find that a Cushing's horse remains surprisingly, simply, a horse.
In Short
- PPID (Cushing's disease) is a hormonal disorder caused by a dysregulated pituitary gland, mainly in horses and ponies from around age fifteen.
- Classic signs: a long coat that sheds poorly, drinking and urinating more, muscle loss over the back, fat deposits, lethargy, and slow-healing infections.
- The biggest risk is laminitis — sometimes the first sign; test any older horse with unexplained laminitis.
- The veterinarian makes the diagnosis with blood testing; the same test then follows up annually on whether treatment is working.
- Management is lifelong: daily medication from the veterinarian, a low-sugar diet, clipping for coat problems, and tight upkeep of teeth, hooves, and deworming.
- Recognized early and managed well, many Cushing's horses still have years of quality of life ahead.
See also: Caring for a senior horse · Laminitis in horses · Seasonal coat care · Glossary: Cushing's disease (PPID) · Level: Considering Your Own Horse