If your older horse is growing a long, curly coat that doesn’t shed out in spring, Cushing’s disease may be the reason. It’s one of the most common hormonal diseases in senior horses and ponies. While it can’t be cured, it can usually be managed well with medication and good care. Here’s what to know about equine Cushing’s disease, also called PPID.
Quick Answer: Equine Cushing’s disease, or pituitary pars intermedia dysfunction (PPID), happens when part of the pituitary gland becomes overactive with age. Signs include a long or curly coat that doesn’t shed, muscle loss, a pot belly, increased drinking and urination, and laminitis. A blood test can help diagnose it, and daily medication (pergolide) controls signs in most horses.
What Is PPID?
PPID is a slowly progressive disease of the pituitary gland, at the base of the brain. Nerve cells that normally control part of the gland degenerate with age. The pars intermedia then enlarges and produces too many hormones.
The Merck Veterinary Manual describes this condition in older horses and ponies, with a long, wavy coat as a hallmark sign.
Who Gets PPID?
- Horses and ponies usually over 15 years old
- Ponies and Morgans may be at higher risk
- It’s estimated to affect a significant portion of horses over 15
Signs of PPID
Early signs
- Delayed shedding in spring
- Patches of long hair, often on the legs or chin
- Decreased performance or energy
- Loss of topline (muscle along the back)
- Regional fat deposits, such as above the eyes
- Laminitis without another obvious cause
Advanced signs
- Long, thick, curly coat (hypertrichosis) that doesn’t shed
- Pot belly and swayback
- Drinking and urinating more
- Excessive sweating
- Frequent infections, such as hoof abscesses or skin infections
- Slow wound healing
- Weight loss
PPID and Laminitis
Laminitis is the most serious complication of PPID. Many horses with PPID also have insulin dysregulation, which increases laminitis risk. See laminitis in horses.
Diagnosis
Your vet may recommend:
| Test | What it measures |
|---|---|
| Resting ACTH | A pituitary hormone; elevated in PPID |
| TRH stimulation test | Pituitary response; helpful in early cases |
| Insulin testing | Checks for insulin dysregulation |
ACTH naturally rises in late summer and fall, so results are interpreted with seasonal reference ranges.
Treatment
Medication
- Pergolide is the main medication. It’s given daily, usually by mouth, and replaces the missing nerve signal to the pituitary.
- Most horses show improvement in energy and coat within weeks to months.
- Your vet will retest periodically and adjust the dose.
- A few horses lose appetite at first. Your vet may start with a lower dose.
Management
- Clipping long coats in warm weather
- Diet: low sugar and starch if insulin dysregulation is present
- Weight control for overweight horses, or calories for those losing weight
- Regular hoof care with your farrier. See hoof care basics.
- Dental care and parasite control
- Watch for infections and treat promptly
Living With PPID
| Task | How often |
|---|---|
| Give pergolide | Daily |
| Check weight and body condition | Monthly |
| Recheck ACTH | As your vet advises, often yearly |
| Farrier visits | Every 4–8 weeks |
| Dental exam | Every 6–12 months |
| Fecal egg count | As advised. See deworming horses. |
Many horses with PPID live comfortably for years. See also caring for senior horses.
When to Call Your Vet
Call promptly if your horse:
- Shows signs of laminitis: shifting weight, reluctance to move, warm hooves
- Has frequent infections or abscesses
- Is losing weight or muscle quickly
Book a visit if:
- Your older horse isn’t shedding normally
- Your horse is drinking and urinating more
Frequently Asked Questions
Is PPID the same as Cushing’s in dogs?
They’re related but different. In horses, the problem is in the pars intermedia of the pituitary, and the treatment is different.
Can PPID be cured?
No, but it can be managed. Most horses need lifelong medication.
Can horses with PPID still be ridden?
Many can, especially with treatment. Your vet will guide you based on hoof health and overall condition.
Is PPID the same as equine metabolic syndrome?
No. EMS involves insulin dysregulation and obesity, often in younger horses. Some horses have both.
What does pergolide cost?
Costs vary by dose and pharmacy, but it’s a daily medication, so plan for an ongoing expense. Ask your vet about approved products and generic options where available.
Will my horse’s coat return to normal with treatment?
Many horses shed out more normally within a season of starting medication, though the coat may not look exactly like it did years before.
Should I clip a horse with PPID?
Clipping helps prevent overheating and sweating in warm weather. Use blankets to replace the coat in cold weather.
This article is for general information only and isn’t a substitute for professional veterinary advice. If you’re worried about your pet’s health, contact your veterinarian or an emergency animal hospital.
