Equine Cushing's Disease (PPID)

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Bakers Hill Veterinary Hospital
4609 Great Eastern Highway
Bakers Hill
WA 6562

08 9574 1061

Bakers Hill Veterinary Hospital’s guide to Equine Cushing's Disease

Click here to download this info as a PDF handout


What is it?

Equine Cushing’s disease, or more properly Pituitary Pars Intermedia Dysfunction (PPID), is one of the most common problems affecting the endocrine (hormonal) system of horses and ponies.

Equine Cushing's disease (PPID) is a disease in which the horse's hormones become unbalanced. A small, non-spreading tumour in a gland in the brain causes overproduction in hormones (in particular cortisol), which creates a state that is similar to being stressed all the time. You know that feeling when you've been awake for 24 or 36 hours straight and you've gotten over the tiredness but you just feel bad/wrong? That's the feeling of having too much cortisol in your body. A horse with Cushing's has too much cortisol all the time, and we can guess that he might feel that way all the time, too. This may make him lose weight, be sluggish, and not be himself. With treatment, we can get back to a normal cortisol level and your horse will likely feel good and gain weight again.


In addition, having excess cortisol is like being really stressed all the time, as far as the body is concerned. That's obviously not going to make your horse live longer or feel better, but more importantly, it may make him susceptible to infection and more likely to have poor blood sugar control, similar to human type-II diabetics. This can, in some cases, contribute to laminitis (founder).

Treating a horse with PPID or Equine Cushing’s is recommended to help the horse feel better, return to his old self, and help reduce the risk of laminitis. Initially, while we are not yet sure that his PPID is under control, we may also want to keep him from having too high of a sugar/carbohydrate intake (avoid grains, grasses, oaten hay). This is part of managing his risk of laminitis, since PPID can lead to a diabetic-like state and we all know that people with diabetes have to be careful about the kinds and amounts of sugars they eat. It’s the same with horses.


PPID is not diabetes, but it has some similarities like the body having trouble handling blood sugar, which can be greatly improved by managing diet. PPID or Equine Cushing’s is also not the same as Cushing’s Disease in humans. It is also important to note that PPID is not the same as Equine Metabolic Syndrome – they are different diseases altogether.



Horses and ponies that are suffering from PPID can show a wide range of clinical signs, all of which are caused by the abnormally high levels of the hormone cortisol circulating in the blood.


Symptoms or clinical signs the horse may show are very varied and can include any of the following:

• Laminitis (Founder)

• Abnormal hair coat – shedding of or excessively long coat (inappropriate for the time of year)

• Abnormal fat distribution – eg fat bulging above the eyes, pot belly

• Excessive sweating

• Increased appetite

• Increased drinking and urination

• Lethargy / poor performance

• Accumulation of fluid in dependent areas – eg sheath

• Recurring infections (eg: sinusitis, foot abscesses)

• Loss of muscle condition

There is not one sign that occurs ALL the time and sometimes it can be hard to detect the disease if none of the “classic signs” are present.



In some cases, a presumptive diagnosis will be made by your vet based on a clinical examination and questions regarding your horse and his recent history. A treatment trial will often confirm whether the diagnosis was correct.

Other times, your vet will want to take one or more blood samples from your horse in order to measure blood levels of various hormones or markers, in order to diagnose the disease. A range of blood tests are available to assist in the diagnosis (and monitoring) of PPID but the most commonly used test is the “Resting ACTH test”, where a single blood sample is taken to measure the level of the hormone ACTH that is abnormally high in untreated PPID cases.


Your horse and PPID

Early identification of horses and ponies with PPID helps to stop the disease early in its course. Although there is no “cure” for the problem, appropriate medical treatment and good routine healthcare can help keep your horse or pony healthy and fit.

Medical Treatment - Although a number of different medications and supplements have been suggested as treatments for Equine PPID, only one has so far demonstrated sufficient benefit and safety to become a licensed treatment. This medication is called Pergolide. It is an oral medication, given once daily. The dose a horse will need to control the symptoms of the disease varies for different individuals and it may take a little while to work out. During this time your vet will work closely with you to determine the correct dose for your horse.

Management changes - Many horses and ponies with PPID are older than 15 years, and so may have other conditions associated with middle age, as well as symptoms directly associated with the disease. With this in a mind, a good program of routine preventative health care can be a great help in managing a horse with PPID.


This should include:

• regular worming

• dentistry

• routine foot care

• good quality, balanced diet