Diet for Horses with Cushing’s Disease: Feeding PPID Horses Safely

Pituitary pars intermedia dysfunction, or PPID, changes how many horses handle weight, muscle, immunity, and sometimes insulin. The diet goal is not the same for every horse. Some PPID horses are thin and lose topline, while others also have insulin dysregulation and a much higher laminitis risk. That is why feeding plans should be built around body condition, dental health, and whether insulin is part of the picture.

In general, forage should stay at the center of the ration. Many horses with PPID do well on mature grass hay with a low non-structural carbohydrate, or NSC, level. If insulin dysregulation or laminitis is present, your vet may want hay tested and may target hay around 10 to 12% NSC or lower on a dry matter basis. If hay cannot be tested right away, soaking can reduce water-soluble sugars, though results vary with hay type, water temperature, and soak time.

Feeds that can push sugar and starch too high include lush pasture, sweet feed, cereal grains, and many commercial treats. A low-sugar ration balancer can help fill nutrient gaps when a horse is eating mostly hay. For thin PPID horses that still need calories, your vet may suggest low-NSC senior feed, soaked beet pulp without added molasses, or added fat rather than more grain.

Medication and diet often work together. Pergolide helps manage PPID itself, but it does not replace careful feeding when insulin dysregulation or laminitis risk is present. If your horse has a long hair coat, drinks and urinates more, loses muscle, gets repeated infections, or has sore feet, it is worth asking your vet whether the diet needs to be tightened and whether insulin testing should be added.

How much is safe depends on whether your horse is overweight, underweight, or dealing with insulin dysregulation. For many adult horses, total forage intake lands around 1.5 to 2% of body weight per day, adjusted by your vet for body condition and laminitis risk. For a 1,100-pound horse, that often means roughly 16.5 to 22 pounds of forage daily on a dry matter basis. Horses that are overweight may be fed closer to the lower end, but severe restriction can be risky and should not be done without veterinary guidance.

If insulin dysregulation is confirmed or strongly suspected, meal size and NSC load matter as much as the daily total. Merck notes that horses with severe insulin dysregulation may need the non-structural carbohydrate amount kept at no more than 0.1 g/kg body weight per meal. In practical terms, that usually means avoiding grain-heavy meals and splitting any concentrate into several small feedings.

Hay soaking may help when hay sugar is too high or unknown. A common approach is soaking fully submerged hay in room-temperature water for about 30 to 60 minutes, then draining well before feeding. Cold-water soaking may require much longer. Because soaking can also remove some nutrients and there is usually some dry matter loss, your vet or an equine nutritionist should help you recalculate the ration.

For thin PPID horses, the answer is not to add large grain meals. Safer ways to increase calories often include more frequent small meals, low-NSC complete or senior feeds, and fat sources chosen for the individual horse. If chewing is poor, soaked hay cubes or pellets may be safer than long-stem hay, but your vet should guide that change.

Diet trouble in a PPID horse may show up as hoof pain before it shows up in the feed tub. Call your vet promptly if your horse becomes foot sore, shifts weight, rocks back onto the hind end, walks stiffly, or seems reluctant to turn. Laminitis is one of the most important complications linked to PPID when insulin dysregulation is also present.

Other warning signs are more gradual. Watch for a pot-bellied look with muscle loss over the topline, unexplained weight loss, a longer or curlier hair coat that does not shed normally, increased thirst and urination, repeated skin or hoof infections, and lower energy. These signs do not all come from diet alone, but they can mean the current feeding plan is no longer matching the disease.

Feed-related problems can also include manure changes, poor appetite after a new feed, choke risk with dry pellets in horses with dental disease, or weight gain in an easy keeper who is getting too much pasture. Treats can be part of the problem too. Apples, carrots, commercial cookies, and molasses-based feeds may seem small, but they can add up in horses that are very insulin sensitive.

See your vet immediately if your horse has acute lameness, bounding digital pulses, heat in the feet, severe depression, stops eating, or shows colic signs. Those changes can signal laminitis, pain, dehydration, or another urgent problem that needs more than a diet adjustment.

Safer alternatives for many PPID horses start with forage choices, not supplements. Tested low-NSC grass hay is often the best foundation. If long-stem hay is hard to chew, soaked hay cubes or hay pellets may work better. A low-intake ration balancer can help cover protein, vitamins, and minerals without adding a large sugar load.

If your horse needs more calories but cannot handle grain, ask your vet about low-NSC senior or complete feeds, plain beet pulp without added molasses, or carefully selected fat sources. These options can support weight and muscle while keeping starch and sugar lower than many traditional sweet feeds. Thin senior horses with PPID often do better on soft, soaked meals fed more often rather than one or two large meals.

Pasture alternatives matter too. Some horses can stay on limited grazing with a muzzle and close monitoring, while others with active laminitis or marked insulin dysregulation may need a dry lot and hay-based plan. Slow feeders can stretch forage time and reduce boredom without forcing long fasting periods.

For treats, think lower sugar and smaller portions. A few pieces of celery, a small amount of cucumber, or a handful of hay pellets may fit better than sugary commercial treats, but even safer treats should be cleared with your vet if your horse has laminitis or insulin dysregulation. The best alternative is the one that keeps the whole ration balanced and realistic for your budget, barn setup, and horse’s medical needs.