Cushing’s Disease in Horses: Causes, Risks & Management & Getting a Diagnosis

Confirming a diagnosis of Cushing’s disease in horses isn’t always easy. Symptoms usually develop gradually and can be similar to other ailments, making it easy to miss or mistake for something else. In this blog post, we look at the symptoms of Cushing’s disease in horses, which horses are most at risk, and the steps you can take if you suspect your horse has Cushing’s disease, including using our Cushings Support remedy for horses.

What is Cushing’s Disease in Horses?

Cushing’s disease, or Pituitary Pars Intermedia Dysfunction (PPID), is a progressive disorder of the pituitary gland - part of the endocrine system which plays a vital role in hormone production and regulation. The condition causes an overproduction of adrenocorticotropic hormone (ACTH) in horses, stimulating the adrenal glands to produce too much cortisol, which in turn disrupts normal bodily functions. 

What Causes Cushing’s Disease in Horses?

Cushing’s disease in horses occurs when neurons in the hypothalamus in the brain that produce dopamine start to degenerate, affecting normal hormone production regulated by the pituitary gland. 

Which horses are at most risk of developing Cushing’s Disease?

• Horses that are over 15 years of age.

• Ponies, Morgans, and Quarter Horses appear to be more commonly affected.

• Horses with a history of insulin resistance or Equine Metabolic Syndrome (EMS).

• Horses with a genetic predisposition to developing pituitary tumours.

Is Cushing’s Disease in horses preventable? 

Unfortunately, Cushing’s disease isn’t preventable, however feeding a balanced diet, keeping weight in check, and managing your horse’s stress levels can help to reduce the risk of them developing this condition.

What Are the Symptoms of Cushing’s Disease in Horses?

The symptoms of Cushing’s disease tend to develop gradually, which can make early detection difficult. Many of the signs are subtle at first and can be mistaken for normal ageing or other health conditions, leading to a delayed diagnosis. This slow progression is why regular monitoring of older horses is crucial. Recognising the symptoms early can lead to management techniques more effectively improving a horse’s quality of life. 

Horses with Cushing’s disease may display one or more of the following symptoms:

• Excessive Hair Growth (Hirsutism): A coat that grows long and curly and doesn’t shed properly in warmer months. 

• Weight Loss and Muscle Wasting: a swayback and potbelly appearance due to muscle loss. 

• Laminitis: Recurrent flareups can indicate insulin resistance due to endocrine disruption. This may also be a sign of Equine Metabolic Syndrome which can be a precursor to Cushing’s disease.

• Increased Thirst and Urination: Constant thirst, drinking more than usual and urinating more frequently. 

• Weakened Immune System: Wounds that heal slowly or won’t heal at all, or wounds that frequently become infected. 

• Fat Deposits: Fat accumulation usually above the eyes, along the neck, or around the tail head.

• Lethargy or Behavioural Changes: Reduced energy levels and noticeable changes in temperament over time.

• Reproductive Issues: Infertility in mares or irregular cycles.

The gradual onset of symptoms can make Cushing’s Disease difficult to diagnose. 

What to Do If You Think Your Horse Has Cushing’s Disease

If you suspect your horse has Cushing’s disease, there are some steps you can take straight away to support their health and wellbeing while you work towards a formal diagnosis. 

1. Evaluate and Monitor

• Start a notebook so you can keep track of symptoms such as coat condition, weight changes, water intake, and energy levels, over time.

• Take regular photos of your horse from a similar angle to document coat growth and overall body condition.

• Check regularly for any signs of laminitis (e.g., lameness, heat in the hooves, shifting weight).

2. Manage

• Feed a low-sugar, low-starch diet to help manage insulin resistance:

• Avoid cereal grains and limit pasture grazing, especially during times of lush grass growth.

• Provide high-quality hay with a low non-structural carbohydrate (NSC) content.

• Limit treats such as apples, carrots and bananas that are high in sugars.

• Feed smaller, more frequent meals to support digestion.

• Consider supplements that support metabolic health, such as magnesium and chromium.

• Support the Immune System. In horses the liver performs more physiological functions than any other organ. Good quality feed and supplements are key, and you can also try our Liver Plus – Equine remedy for additional support.

• Use our Cushings Support Remedy. If Cushing’s symptoms are present, it’s safe to start dosing with this remedy to provide support while you seek a formal diagnosis. We recommend dosing for an initial 4 weeks, then discontinuing if there is no noticeable improvement. 

• Clipping: If your horse struggles to shed its winter coat, clipping can help regulate temperature and prevent overheating.

• Hoof Care: Regular farrier visits are crucial to manage laminitis risks. Our LamiPrev remedy is formulated to support horses who are prone to laminitis attacks, while our LamATK remedy provides support during a flareup. Both can be used alongside veterinary care. Read more about understanding the causes and symptoms of laminitis, or take a look at other remedies in our hoof care range. 

• Shelter and Comfort: Ensure adequate shelter and provide a blanket on cooler nights, as horses with Cushing’s may have trouble regulating their body temperature.

• Dental and Veterinary Care: Maintain regular dental checkups to support digestion and overall health.

3. Seek Veterinary Guidance

While monitoring and management can provide short term support and quality of life, it’s important to get a proper diagnosis and treatment plan in place. Your veterinarian may perform tests such as:

• ACTH Blood Test: Measures ACTH levels to determine if the pituitary gland is overactive.

• Dexamethasone Suppression Test: Evaluates cortisol response.

• Insulin Testing: Determines if insulin resistance is present.

Is Cushing’s Disease in horses curable? 

Unfortunately, no, which is why it’s essential to have a management plan in place and seek the advice and guidance of your vet. 

Final Thoughts

A horse with Cushing’s disease can have a good quality of life when managed effectively through diet, care and veterinary support. 

General Disclaimer

Our remedies are formulated to support the natural immune system of horses, pets, and livestock. We do not claim to treat, medicate or cure any health conditions. If you are worried an animal may be in pain or suffering please contact your veterinarian.