Fellow equine enthusiasts unite. As horse lovers, we never want anything bad to happen to our beloved horses. However, with aging, challenges are naturally going to arise–same as they do with people.
Cushing’s disease in horses, or Pituitary Pars Intermedia Dysfunction (PPID), is an endocrine disorder in 20% to 33% of older horses. It impacts the pituitary gland, which regulates hormones that control various bodily functions.
Cushing’s disease can lead to a range of symptoms and is progressive, meaning that without intervention, symptoms will often worsen over time. It is more common in horses over 15 years old, but can occur in younger horses as well.
At BioZyme®, our motto, care that comes full circle, encompasses every animal and every person who cares for those animals. We know that when we care for animals, they will take care of us in return. We’ve created Vitalize®, a line of supplements for horses with proven solutions to keep your animal healthy and performing. As you can imagine, everyone on the Vitalize team are horse lovers just like you. That’s why we created this educational piece – to share more about Cushing’s disease, its signs, its treatment and how to make your horse the most comfortable.
Signs of Cushing’s Disease in Horses
Horses with Cushing’s disease display various of symptoms, which can sometimes make early diagnosis challenging. Many signs result from the overproduction of hormones, particularly adrenocorticotropic hormone (ACTH), leading to an overproduction of cortisol. Common signs include:
Hirsutism (Abnormal Hair Growth)
One of the hallmark signs of Cushing’s disease in horses is a long, curly coat that fails to shed normally. The horse may appear to have a heavy winter coat even in warmer months. The coat may be noticeably coarse or curly.
Lethargy & Poor Performance
Affected horses may exhibit reduced energy levels and a general unwillingness to perform tasks. They might seem lethargic and disinterested in activities they previously enjoyed, which impacts their performance, especially in competition or working horses.
Muscle Wasting
Cushing’s disease in horses often leads to loss of muscle mass, especially along the topline. This is partly due to the breakdown of proteins in muscles due of elevated cortisol levels. Over time, muscle wasting can contribute to a “pot-bellied” appearance.
Increased Drinking & Urination
Horses with Cushing’s disease often drink more water than typical and urinate more frequently, scientifically known as polydipsia and polyuria, respectively. This is due to the effects of excess cortisol on kidney function.
Laminitis
This painful and potentially life-threatening inflammation of the hoof’s laminae is a serious complication of Cushing’s disease. Laminitis can cause lameness and reluctance to move, and if not managed promptly, it can lead to irreversible hoof damage.
Abnormal Fat Deposits
Cushing’s disease in horses can sometimes cause the horse to develop unusual fat deposits, such as a cresty neck or fat around the tailhead, eyes and shoulders.
Frequent Infections & Poor Wound Healing
Elevated cortisol levels suppress the immune system, which makes horses more susceptible to infections. They may experience recurrent skin infections, respiratory infections and delayed wound healing.
Sweating Abnormalities
Some horses with Cushing’s disease may sweat excessively, while horses may sweat very little, leading to thermoregulation issues.
Behavioral Changes
Cushing’s disease in horses can lead some horses to exhibit mood changes, becoming more irritable or aggressive, likely due to hormonal imbalances.
Every horse is an individual, and each horse will show different symptoms and signs of Cushing’s disease. Some horses could show a combination of these symptoms, while some might show just one distinct sign. The earlier you see a sign of Cushing’s disease, the easier it will be to diagnose and treat this condition in your horse.
Diagnosis of Cushing’s Disease in Horses
Diagnosing Cushing’s disease can be challenging, especially in its early stages, as its signs often overlap with those of other conditions common in aging horses. At BioZyme, we always recommend establishing a relationship with your veterinarian, no matter what species you care for. It is important for your veterinarian to know your horse when it is healthy. That way, when health challenges do arise, it is easier for the vet to recognize them and make a diagnosis.
Although Cushing’s disease in horses isn’t always easy to pinpoint, veterinary professionals can use several diagnostic methods to confirm its presence. Additionally, veterinarians consider factors like age, history and seasonality when interpreting test results. Here are 4 diagnostic methods veterinarians use to determine Cushing’s disease in horses.
- Physical Examination & Medical History
A veterinarian will evaluate the horse’s symptoms, age and overall health. A physical exam often focuses on characteristic signs like an abnormal coat, muscle wasting and potential signs of laminitis, which we have previously discussed.
- Endogenous ACTH Concentration Test
This blood test measures the horse’s ACTH levels, which are typically elevated in horses with Cushing’s disease, especially in the fall. Elevated levels of ACTH suggest PPID, but ACTH levels can vary with seasons, so it’s important to consider seasonal reference ranges.
- TRH Stimulation Test
Thyrotropin-releasing hormone (TRH) stimulates the pituitary gland. In horses with Cushing’s disease, this stimulation leads to an exaggerated release of ACTH. This test can be instrumental in diagnosing early-stage PPID.
- Overnight Dexamethasone Suppression Test
This test is less commonly used today due to its potential to induce laminitis in susceptible horses. It is occasionally used in controlled environments. In healthy horses, administrating dexamethasone (a synthetic steroid) suppresses cortisol production. In horses with Cushing’s disease, cortisol levels remain high even after dexamethasone administration.
Accurate diagnosis may require a combination of these tests and careful monitoring of symptoms over time.
Prevention of Cushing’s Disease in Horses
There is no surefire way to prevent Cushing’s disease in horses. However, certain management practices can help support overall health and potentially reduce the severity of symptoms. Genetic factors and age contribute significantly to the risk, so early detection and management are the best strategies.
Although prevention isn’t 100% possible, we like to keep our horses as healthy and comfortable as possible.
Routine Health Monitoring
Regular veterinary check-ups can help catch signs of Cushing’s disease early. Horses older than 15 should have annual exams to monitor for signs of Cushing’s and related conditions like laminitis.
Diet & Weight Management
Obesity can intensify symptoms of Cushing’s disease, so maintaining an appropriate diet is important. Horses prone to obesity or dealing with insulin resistance may benefit from low-sugar, high-fiber diets. Make sure to carefully manage grazing, as lush pasture grass can impact insulin resistance and increase the risk of laminitis.
Foot Care & Laminitis Management
Preventive measures for laminitis are especially important in horses with or at risk for Cushing’s disease. Regular farrier visits, proper hoof trimming and diligent monitoring for signs of lameness can help manage the risk.
Stress Reduction
Stress can worsen symptoms in horses with endocrine disorders, so reducing sources of stress—such as changes in routine, transport or competition—is beneficial.
Exercise
Exercise helps maintain muscle mass and reduces the risk of obesity, which may mitigate some symptoms of Cushing’s disease. However, exercise should be moderate and adjusted according to the horse’s energy levels and overall health.
Treatment of Cushing’s Disease in Horses
Treatment for Cushing’s disease focuses on managing symptoms, slowing disease progression and improving the horse’s quality of life. Experts recommend several treatment options and management practices . Remember, work closely with your veterinarian for the treatment protocol that best suits your individual horse.
Pergolide
Pergolide, with the label name Prascend, is the only FDA-approved medication for treating Cushing’s disease in horses. It is a dopamine agonist that helps regulate the pituitary gland’s activity and reduce excessive ACTH production. You administer pergolide orally, usually once daily. With the guidance of your veterinarian, you can always adjust the dosage based on response. Side effects are generally mild, but some horses could initially experience a decrease in appetite.
Cyproheptadine
Use this drug in combination with pergolide for horses that do not respond well to pergolide alone. Cyproheptadine has antihistamine properties and can help control some symptoms. However, its efficacy is generally considered lower than pergolide, so it is a secondary option.
Management of Laminitis
Laminitis is one of the most challenging complications of Cushing’s disease. Treatment may include anti-inflammatory medications, supportive shoeing and dietary modifications. Reducing access to lush pasture and feeding low-starch diets can help prevent laminitis flare-ups.
Regular Dental & Hoof Care
Horses with Cushing’s disease are prone to infections and metabolic issues, so maintaining oral and hoof health is essential. Regular dental checks and farrier visits can prevent complications and improve the horse’s comfort.
Monitoring & Adjusting Dosages
Pergolide dosage often needs to be adjusted over time as the disease progresses. Regular blood tests to monitor ACTH levels, insulin levels and overall health markers are necessary to ensure effective treatment. Some horses may require additional therapies or dietary adjustments as the disease advances.
Environmental Adjustments
Horses with Cushing’s disease may have thermoregulation issues, so blanketing in colder weather and providing shade or fans in hot weather can improve their comfort. Clipping excess hair in horses with abnormal hair growth can help them stay cooler in warmer months.
Nutritional Support
Horses with Cushing’s disease may benefit from specific supplements, including those containing omega-3 fatty acids, antioxidants and minerals like magnesium and chromium. Omega-3 fatty acids can have anti-inflammatory effects, while chromium and magnesium help regulate glucose metabolism, which can benefit insulin-resistant horses.
Trust Safe, Accurate Products Made by Vitalize
Speaking of nutritional support for your horse, Vitalize offers several supplements that could help with the impact of Cushing’s disease in horses.
We have decades of research helping us provide horse owners with premium equine supplements. Why do we put this premium on science-backed products? We want horse owners like you to know they can trust the safe, accurate products with a Vitalize label. Our team has undergone numerous quality training courses, including Safe Feed, Safe Food, FAMI-QS and others.
Vitalize products are research-proven, and our manufacturing facility utilizes an ionophore-free closed production system to ensure a safe, accurate product. BioZyme has taken great care to ensure that our Vitalize products are safely made and have no risk of ionophore contamination.
In addition, BioZyme Inc., the maker of Vitalize, is a member of the National Animal Supplement Council (NASC). All Vitalize products carry the NASC Seal, meaning our production processes meet the highest quality standards for equine supplements on the market.
Furthermore, Vitalize equine supplements are low in non-structural carbohydrates (NSC) or simple sugars and starches. While these carbohydrates can be an important part of a balanced diet, some horses may be more sensitive to them, including your horses with Cushing’s disease. Using low NSC formulas allows Vitalize products to be used safely across all horses and ponies.
We take the care that comes full circle very seriously when it comes to our equine companions.
Vitalize Products to Consider
If you are interested in getting some Vitalize products that could help your horse with Cushing’s disease, here are a few that our team recommends.
Vitalize® Equine Vitamin & Mineral Supplement
Vitalize Equine Vitamin & Mineral Supplement is a highly fortified, loose vitamin and mineral supplement for horses designed to support nutritional and digestive health.
This is the simple choice for the essential nutrients often left lacking in forage diets but needed for horses to thrive.
Vitalize® Equine Protein Pellet
Vitalize Equine Protein Pellet is a pelleted, natural 28% protein supplement for horses, fortified with vitamins and minerals.
This makes our protein pellet a great choice for horses with Cushing’s disease that might be losing muscle mass or simply lacking appetite. Additionally, we’ve boosted the levels of most vitamins and minerals from the Equine Vitamin & Mineral Supplement to provide extra support for those who need it.
Vitalize® Hyaluronex® Joint
Vitalize Hyaluronex Joint is a liquid product for horses designed to support sustainable soundness using hyaluronic acid and antioxidants. Hyaluronex Joint helps maintain a normal inflammatory response and supports normal exercise recovery. It supports bone, joint and soft tissue health. Most importantly, it contains MHB3, a high molecular weight hyaluronic acid with 8 U.S. Patents.
Vitalize® Blazin’
Vitalize Blazin’ is a liquid product for horses designed to support normal recovery from heat stress and exertion. This might be a great cooling solution for the hotter periods to help cool your horse.
What Makes Vitalize Better?
We know that 70% of the immune response starts in the gut. That is why most of our products contain AO-Biotics® Amaferm ®, a research-proven prebiotic designed to enhance digestibility. By keeping the horse’s digestive system healthy and feeding supplements that are low in NSC, you are taking the first step to enhancing equine health. A healthy horse is likelier to have healthy feet and legs, keeping them feeling good and sound. But wait, there is more!
At BioZyme, we know how important joint health and soundness is to all species. Therefore, we utilize the gold standard of hyaluronic acid (HA) – MHB3® Hyaluronan.
What Makes MHB3 Different?
Yes, there are many hyaluronic acids on the market. However, what makes MHB3 unique is its liquid formulation. Because HA molecules are extremely water-loving, they can hold up to 1,000 times their weight in water.
Dry forms of HA (pills, tablets, capsules & powders) do not have enough time to fully hydrate before passing through the body’s digestive tract. Essentially, the body struggles to absorb dry forms, making them much less effective.
The primary absorption points for HA throughout the body are in the mucosal tissue of the mouth and the upper parts of the throat. To take advantage of the absorption points, the product must be bioavailable for immediate absorption as soon as it hits your horse’s mouth.
Giving your horses just two pumps of Vitalize Hyaluronex per day may help reduce inflammation in horses due to exercise, training and competition. Support a normal inflammatory response with Hyaluronex Joint and give your horses the joint support they need and deserve.
Give your Horses a Good Gut Feeling & Sustainable Soundness
We know that Cushing’s disease isn’t preventable. But, if you could give your horses good health and soundness as long as possible, wouldn’t you?
It’s time to add Vitalize to your feed room. You can purchase it online on our website or through one of BioZyme’s online retailers.
If you want to shop locally, you can search for your local BioZyme dealer on our website.
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You can also view all the other Vitalize equine and canine products on our website.
