What is Cushing's Disease in Horses?
Cushing's disease otherwise known as pars pituitary intermedia dysfunction (PPID) affects the horse’s pituitary gland. The pituitary gland is located at the base of the horse’s brain and is responsible for producing and releasing hormones that regulate many of the horse’s bodily functions.
In cases of Cushing's, hormone production becomes dysregulated resulting in a range of symptoms that affect the horse’s body in several ways. Cushing's is a degenerative condition meaning it will progress as your horse ages.
What Are the First Signs of Cushing's Disease in Horses?
Early detection is vital. What are the first signs of Cushing's disease in horses? Horse owners should typically look for:
- A thick, curly coat that fails to shed
- Behavioral changes, lethargy, and weight loss
- Increased sweating, drinking, and urination
Symptoms of Cushing's Disease in Horses
The symptoms of Cushing's disease in horses may vary but commonly include:
- Frequent episodes of laminitis
- Abnormal fat deposits
- Recurrent infections due to a weakened immune system
- Increased sweating and lethargy
Causes and Risk Factors
Causes of Cushing's Disease in Horses
Cushing's disease is almost always diagnosed in older horses with the average age being 19. It is estimated that at least 20% of horses over 15 may be affected.
Whilst primarily seen in older horses, Cushing’s can affect younger horses too, so symptoms shouldn’t be dismissed just because the horse doesn’t fall within the typical age bracket.
Any breed of horse, pony, or donkey can develop Cushing's disease, however incidents seem to be much greater among Native Ponies. Horses and ponies with a pre-existing diagnosis of Equine Metabolic Syndrome (EMS) are also put at a greater risk of developing Cushing's.
How is Cushing's Disease Diagnosed?
Diagnosis of Cushing's disease can often be made from the presence of clinical signs, however vets will confirm a diagnosis through blood testing. The following tests are used to detect the disease in horses:
- Adrenocorticotropic hormone (ACTH) test: Elevated levels of ACTH can indicate Cushing’s disease.
- A thyrotropin-releasing hormone (TRH) stimulation test: This test involves injecting a small amount of TRH into the body and assessing the levels of ACTH in the blood as a response to this. As with blood tests, a high level of ACTH hormone following TRH stimulation is indicative of Cushing's disease.
In the early stages of the disease, blood tests can sometimes give false readings meaning they may not be the most accurate diagnosis tool. They tend to be more accurate as the condition progresses.
Treatment for Cushing's Disease in Horses
Cushing's Disease in Horses Medication
Treatment involves long-term use of Prascend, a drug that regulates ACTH levels to manage symptoms and slow progression. It can affect your horse’s appetite especially when it is first introduced.
If your horse is unable to consume adequate amounts of forage, we recommend providing them with a forage replacement mash to help maintain condition and optimal gut function. Regular vet monitoring is essential to adjust dosages and ensure effective management.
How to Prevent Cushing's Disease in Horses
Unfortunately, there is no known way to prevent or cure Cushings disease, however the symptoms can be well managed to improve longevity and quality of life through:
- Regular veterinary check-ups
- A carefully controlled diet low in sugar and starch
If you are concerned about the sugar and starch content of your horse’s hay, this can be soaked before feeding to reduce it. If you are unsure about whether or not to soak your hay, several labs will offer a forage analysis that can determine the precise sugar and starch content which can help owners make a more informed decision.
Access to lush grazing should be avoided. Instead, strip grazing techniques should be adopted through the Spring and Summer months to limit grass intake. In the Winter, grazing on frosty paddocks should be avoided as frosty grass tends to have a much higher sugar content.
Feeding and Nutrition
Feed for Horses with Cushing's Disease
Feeding horses with Cushing's disease requires special care. Avoid feeds high in sugar and starch, particularly those with molasses or cereals. Soaking hay can help reduce sugar content; aim for combined sugar and starch levels below 10%.
Offer forage replacements like unmolassed beet products (e.g., Speedibeet) and hay cubes with low sugar and starch content.
If your horse struggles to maintain weight, additional calories can be provided in the form of healthy fats such as linseed oil or micronised linseed. We recommend avoiding traditional conditioning mixes for horses with Cushing’s as these are often high in sugar, starch, and cereals.
Can You Ride a Horse with Cushing's Disease?
Yes, gentle daily exercise is beneficial as it helps regulate blood glucose levels. Adjust exercise intensity based on the horse’s condition, and avoid overexertion as the disease progresses.
Managing Symptoms and Enhancing Quality of Life
Daily Care and Symptom Management
- Clipping coats: Horses with thick, curly coats may need regular clipping to manage sweating and maintain body temperature.
- Rugging in winter: Horses with Cushing's often need heavier rugs due to their decreased ability to regulate body temperature.
- Appetite concerns: Prascend may reduce appetite initially. Providing forage replacement mashes or high-fibre alternatives like Speedibeet can help maintain weight.
Supplements for Cushing's Disease in Horses
Equinutritive offers supplements with negligible sugar and starch, making them safe for horses with metabolic conditions. Our Golden Oldies supplement is ideal for older horses in need of all-round support. It includes ingredients like Boswellia, Milk Thistle, Rosemary, Bilberry Leaf, Burdock Root, and Meadowsweet to support liver health, metabolic rate, and overall well-being.
Always consult with a vet before introducing supplements alongside medication.
Contact Our Nutritional Experts
Managing cushing's disease in horses involves a combination of proper medication, a controlled diet, and regular veterinary care. Feeding older horses can be a little more complex. If you would like dietary advice please email enquiries@equinutritive.com and a member of our knowledgeable nutritional team will be more than happy to help.