My 23 yr old QH mare was diagnosed today with Cushing’s. I am starting her on Pergolide ASAP. Can you please advise me about the diet I should provide? Rice bran pellets (Vitabran) and alfalfa was my plan. I had also just put her on glucosamine as a preventative measure. Should I hold off on that until we stabilize the Cushing’s? Or do you recommend Cetyl-M for horses as a daily joint supplement? Karen
Managing a horse with Cushing’s Disease (Pituitary Pars Intermedia Dysfunction or PPID) can be challenging because some horses need to lose weight, some need to gain weight, and some are just right. So step one in developing the correct diet for her is assessing her body condition score and deciding if she is heavy and needs less calories, thin and needs more calories or just right and should stay on the same diet.
Step two is finding out if insulin resistance (failure of the body to respond properly to insulin) is a secondary component of her condition since that will affect her diet also. Experts generally recommend that horses with Cushing’s Disease avoid feedstuffs high in non-structural carbohydrates (sugars or starches) and this is especially true if they also have Insulin Resistance.
Foods high in sugars and starches are grains, treats, grass pasture especially at the end of the day, and some grass hay. Alfalfa hay generally doesn’t have as much sugar and starch as grass hay but some horses prone to laminitis (horses with Cushing’s and Insulin Resistance) are sensitive to it so add it to your horse’s diet slowly, especially if she hasn’t had alfalfa before.
You may be just fine with a low-sugar/starch hay that you either sent off for analysis and found to be less than about 10 or 12% NSC or that you soak in water to remove sugars. Rice bran—as long as it’s fortified with calcium to offset its naturally high phosphorus content—is a good choice for adding calories back to the diet through fat. I personally like molasses-free beet pulp as a feed source, because it has a nutritional profile similar to hay, doesn’t cause a spike in blood sugar and therefore insulin, and provides energy from bacterial fermentation of fiber.
Since fortified grain is probably not a good idea, make sure she is still receiving a complete and balanced diet by adding in a multi-vitamin/mineral supplement or ration balancer. And because Cushing’s is thought to be caused in part by oxidative stress on aging brain tissues, add in antioxidants like Vitamin E, Vitamin C (beneficial for most older horses), Selenium if your area is low in it, and others.