Managing and Understanding Equine Cushing’s Disease Through Diet

Sharing is caring!

Equine Cushing’s disease, also known as pituitary pars intermedia dysfunction (PPID), is a common endocrine disorder affecting older horses. A benign tumor causes this condition on the pituitary gland, which disrupts hormonal regulation. An estimated 10-30% of horses over 20 years old suffer from PPID. If left untreated, it can lead to serious secondary issues like laminitis, muscle wasting, infections, and excess thirst and urination. Fortunately, PPID can be well-managed through a combination of medication and dietary strategies targeted at regulating blood sugar, supporting health, and preventing complications.

What is PPID?

PPID develops when the pituitary gland produces excess hormones like cortisol and ACTH. This throws off the carefully controlled feedback loops regulating metabolism, immunity function, coat shedding, and appetite. The most common cause is a benign tumor in the intermediate lobe of the pituitary, compromising hormonal signaling. Risk increases with age, and certain breeds, like Ponies, appear more genetically prone.

Excess cortisol mimics Cushing’s syndrome in humans, so veterinarians adopted this term. Early detection and treatment are key to slowing progression and minimizing secondary issues like muscle wasting and laminitis, which can greatly impact quality of life.

Signs of PPID in Horses

Early detection and diagnosis of PPID are crucial for optimal management. Here are some common signs to watch for:

  • Changes in hair coat: Failed coat shedding, resulting in a long, thick coat that does not shed properly, is a classic sign. However, some breeds naturally carry longer coats. Observing other Horse disease symptoms is critical as well.
  • Muscle loss and weakness: Due to disrupted protein synthesis, PPID often causes muscle wasting and weakness despite a normal to increased appetite. Fatty deposits may accumulate as well.
  • Fat distribution abnormalities: Accumulations of fat in abnormal places like above the eyes (“fatty eyebrows”), over the tail head, sheath or udder areas, and more distinguishing PPID fat from typical weight gain patterns.
  • Increased thirst and urination: Excess cortisol compromises fluid regulation, often markedly increasing water intake and urination as the horse tries to flush excess sugars from its system. Stall floors may remain wet from constant peeing.
  • Lethargy and reduced stamina: Despite increased hunger, horses demonstrate lower energy levels and tire more quickly due to muscle wasting and disrupted metabolic processes.
  • Susceptibility to laminitis: Insulin resistance and high blood sugar brought about by PPID significantly increase laminitis risks. Catching and managing PPID early on can help prevent this excruciating and potentially life-threatening hoof condition.
  • Recurrent infections: Compromised immunity due to cortisol overproduction reduces resistance to bacterial and fungal infections, including skin conditions and sinus issues. Slow-healing wounds are also common.

Diagnosing PPID

Owners noticing potential PPID symptoms should have their horses promptly evaluated by a veterinarian. They will perform a thorough physical exam, assessing body condition, hair coat, fat deposits, muscle loss, hoof health, and more for characteristic signs. Two main lab tests help confirm a diagnosis:

  • Resting ACTH levels: Measures adrenocorticotropic hormone levels in a blood sample. Elevated levels indicate pituitary dysfunction.
  • Dexamethasone suppression test: Evaluates cortisol response to an injected cortisol-like medication—lack of suppression points to PPID.

Once a PPID diagnosis is confirmed, determining the best course of treatment can greatly help manage the condition.

Treating PPID

In most cases, PPID requires lifelong treatment through prescription medication alongside dietary adjustments. Several FDA-approved medications help control the disease:

  • Pergolide: This dopamine agonist improves the regulation of hormonal pathways disrupted by PPID. It is very effective at managing symptoms long-term.
  • Cyproheptadine: An antihistamine that helps block ACTH, lowering cortisol levels. Often used alongside pergolide.
  • Trilostane: An oral medication that limits excess cortisol production and its effects on the body. Requires close veterinary monitoring.

While drugs form the cornerstone of treatment regimens, optimizing the horse’s diet also plays a crucial role in managing PPID.

Dietary Management for Horses with PPID

Diet for Cushing’s horses is critical in managing PPID alongside medication. A carefully formulated Horse Nutrition diet helps regulate blood sugar levels, minimize the risk of laminitis, and support overall health. Here are key dietary considerations for horses with PPID:

  1. Limit sugars and starches: To control blood sugar spikes, eliminate high-glycemic feeds like cereal grains. Restrict intake of molasses as well. Emphasize good quality forage, fat, and fiber instead.
  2. Control calorie intake: Avoid obesity, limit pasture access, substitute some hay for soaked hay cubes, and possibly use a grazing muzzle. Consult your vet on ideal body condition targets.
  3. Ensure adequate vitamins and minerals: PPID horses may need supplementary vitamins E, C, and B along with magnesium and chromium to regulate insulin and glucose best. Add a low-iron mineral blend.
  4. Monitor pasture access: Grazing on high-sugar spring or fall grass poses laminitis risks. Use a grazing muzzle, limit daytime turnout, or rotate access to reduce exposure.
  5. Slow down hay consumption: Divide daily rations into several small hay net feedings rather than allowing free choice hay, which PPID horses may overeat, boosting blood sugar.
  6. Soak hay: Soaking high-sugar hay like alfalfa for 30-60 minutes before feeding will help leach some sugars for steadier glucose levels.
  7. Consider fat supplements: Rice bran or vegetable oil lowers glycemic response compared to high starch/sugar feeds. Ensure proper vitamin E levels, given the risk of oxidative damage to muscles and nerves.
  8. Electrolytes balance: Monitor for low blood potassium levels, which may require potassium chloride supplementation under veterinary advisement.
  9. Offer fresh, clean water: Increased thirst means providing plentiful access to fresh water – test mineral levels if on well water. Monitor consumption.
  10. Feed small, frequent meals: Divide daily calorie needs into 4-6 mini-meals, allowing 2-3 hours of non-grazing prior to each to prevent prolonged high insulin levels.


Equine Cushing’s disease significantly impacts horse health, especially later in life. The complex hormonal changes brought about by PPID can compromise everything from muscle maintenance to immunity to glucose regulation. That’s why early evaluation of symptoms and specialized veterinary diagnosis followed by appropriate medical treatment alongside proper horse nutrition and disease management are imperative.

By working closely with your vet to develop the optimal diet for balancing blood sugar, delivering vital nutrients, and preventing issues like laminitis, horses with PPID can continue to lead comfortable lives in spite of the condition. Ongoing observation and a carefully tailored feeding plan addressing unique horse nutrition considerations in the context of this particular equine disease can go a long way in minimizing associated health complications. With the right dietary adjustments and medications, horses can manage PPID successfully for years. However, owners must educate themselves on the hallmark symptoms of equine Cushing’s to best support their aging companions through proper horse disease detection, treatment, and nutritional support unique to these horses’ needs.

Sharing is caring!

Speak Your Mind