Integrated Nutritional Support for Cushing’s Horses
The approaches to biological health challenges — including treatment of insulin-resistant and Cushing’s horses — are very different between Eastern and Western medicine.
The driving principle of Western medicine is reductionist medicine, which treats the symptoms, often without addressing the root cause. In Eastern medicine, the driving principle is balancing the mind/body/spirit as a unified, organic whole.
When we combine the two approaches, our horses get the Western benefits of life-saving medications and the Eastern holistic support of foods and plants.
Metabolic diseases are very common in horses, from insulin resistance to equine Cushing’s disease. Managing these horses can be challenging and stressful for both the owners and the animals. One thing is for sure with these horses: we need to approach them as individuals, paying attention to what works best for each.
I had a retired pony at my farm for 13 years. She came to me after being retired from the children’s hunter division at age 18. At age 20, she was diagnosed with mild Cushing’s Syndrome. The vet wanted her to start on pergolide. We did this and she refused to eat. I tried all sorts of tricks, but that pony would spit it out, and then turn her nose up at her food and hay. So I asked the owner if we could take a different approach, which she agreed to.
The pony was in the plump Cushing’s stage, so I started adding kelp to stimulate her thyroid gland and speed up her metabolism. She was also out in a herd 24/7 with run-in sheds, walking up and down hills. For a number of years she did great on this simple regimen of movement and kelp, a whole-food diet of timothy/alfalfa pellets, Cool Stance, chia, BioStar’s Optimum EQ, and low-NSC hay.
At the age of 28, her Cushing’s changed and she started losing weight. I stopped the kelp. The vet wanted me to put her on Prascend (pergolide), which I gamely tried, but the pony once again lost her appetite and acted lethargic and unhappy. I took her off the Prascend, and began managing her with some Ayurvedic herbs: organic Indian gooseberry, holy basil, and chaste tree berry, plus extra magnesium and higher-fat foods like coconut meal, hemp and camelina oils and chia seeds. She put on weight and muscle and lived another three healthy years until her heart gave out at age 31.
Every Horse is Different
Not all metabolic horses can manage and thrive without medications. Some can, some can’t. Some insulin resistant horses do spectacularly well on the medication Thyro-L, and others don’t seem to improve at all. Some horses do extremely well on pergolide while others cannot tolerate it.
The Role of the Pituitary Gland
Cushing’s disease in horses is different than in dogs and humans. In horses, Cushing’s is associated with tumors of the pars intermedia section of the pituitary gland. In dogs and humans, Cushing’s is usually associated with either tumors of the pars distalis area of the pituitary or tumors of the adrenal glands. According to Frank Andrews, DVM, an associate professor of equine medicine at the University of Tennessee’s College of Veterinary Medicine, “In horses, adrenal tumors aren’t seen.”
The Role of Cortisol
Cortisol plays an important role in Cushing’s Syndrome. Under normal circumstances, cortisol production is balanced by the hormone CRH, which stimulates ACTH from the pituitary. Pituitary tumors cause excessive production of cortisol from the adrenal gland, causing cortisol levels to rise dramatically. When cortisol levels are too high, various functions are negatively affected, reducing the ability to break down carbohydrates, balance insulin, or regulate muscle and connective tissues. The result of prolonged exposure to elevated levels of cortisol can cause immunosuppression.
This drug was used on humans to treat Parkinson’s disease until 2007. The FDA withdrew pergolide from the human market due to cardiac complications in some humans. This problem has not been seen in horses. Pergolide is used for Cushing’s disease in horses because it works by binding with receptors in the brain that control the production of dopamine, which is deficient in Cushing’s horses. Pergolide helps to increase dopamine, thus reducing ACTH and cortisol.
Support Through Food
We can support increased dopamine production with foods high in tyrosine, which is an essential amino acid involved in brain signaling molecules including dopamine. Foods high in tyrosine include alfalfa, spirulina, pumpkin seeds, hemp seeds/hemp protein, lentils, and sesame seeds. These foods are not contraindicated with pergolide.
- Timothy Pellets (or Alfalfa/Timothy Pellets or Alfalfa Pellets)
- Chia Seeds
- A small amount of Coconut Meal (Cool Stance) or Coconut Oil
- Adding BioStar’s Optimum EQ Healthy Weight will supply the spirulina for dopamine production plus organic kelp for thyroid support, and the fat and sugar regulator Crominex® 3+.
A basic whole food diet for underweight Cushing’s horses:
- Alfalfa Pellets (or Timothy/Alfalfa Pellets)
- Chia or Flax
- Coconut Meal (Cool Stance) or Renew Gold
- Adding BioStar’s Optimum EQ 2.0 Senior provides the spirulina and pumpkin seeds for dopamine production. Sometimes I add Gold Star camelina oil for additional fat and vitamin E, and BioStar’s Bio Yeast EQ to help the body digest fiber in the hindgut.
Also, hay needs to be tested. You want a total NSC value of 10-12% or less.
Plants from Eastern Medicine
There are specific plants in Ayurvedic medicine that can support Cushing’s horses as well as insulin resistant horses.
Indian gooseberry – Known as amla, this highly revered plant is one of the rasayanas (that which is rejuvenative for the entire body system). Amla stimulates microcirculation and helps to promote healthy blood sugar levels. Amla also supports the immune system, and tonifies the body’s tissues.
Holy Basil – Known as Tulsi, it is considered one of the most sacred plants in the ancient Ayurvedic texts. Its name in Sanskrit translates to “the incomparable one”. Classified by Western herbalists as an adaptogenic plant (like ginseng, maca, ashwaganda and schizandra), tulsi balances the body system—endocrine, glandular, and circulatory. It is commonly used to support the adrenal gland and reduce cortisol.
Schizandra Berry – Used in Traditional Chinese Medicine for over 2,000 years, it is classified as an adaptogen herb: one that reduces stress hormones in the blood, and possesses significant antioxidant and anti-inflammatory activity.
Milk Thistle – It’s traditionally used to detoxify the liver and provide liver support. But recent research from Austria has shown that the endotoxins which play a role in laminitis can be reduced with milk thistle and its powerful active compound silymarin (Reisinger, N., Schaumberger, S., Nagl, V., Hessenberger, S., & Schatzmayr, G., 2014).
From Western Medicine
Two important minerals, chromium and magnesium, can help reduce cresty necks and fat pads. These minerals need to be in a bioavailable form. Chromium picolinate or trivalent chromium are the most bioavailable. Amino acid-chelated magnesium or magnesium malate are much more bioavailable than magnesium oxide.
BioStar’s Tri Dosha EQ
This formulation blends the plants of the East with the nutrients of the West for an integrated approach to managing Cushing’s horses. Is not contraindicated with pergolide, and may be able to reduce pergolide dosage in some horses.
Tri Dosha EQ can be used by insulin resistant horses, and is recommended during spring and fall seasons when the sugar content of grasses is highest. If your horse is in an area that is experiencing drought, the sugar in the grasses will be high, so it’s advisable to supplement with Tri Dosha EQ.
Diet and Exercise
Diet and exercise are key components in the management of Cushing’s horses and insulin resistant animals. Watch those sugary treats. If you want to give your metabolic horse a food reward, go with alfalfa pellets, pumpkin seeds, and sliced almonds. If you really need to feed carrots, just feed a few small pieces—not the entire carrot.
Although we can’t “cure” metabolic diseases in horses, Cushing’s and insulin resistance can be managed so that affected horses can still live long, happy lives.
About the Author: With over 30 years experience in the equine and human supplement industry, Tigger Montague knows nutrition from the synthetic side as well as the whole food side. She started BioStar US in 2006 with formulas she created in her kitchen. Before she started the company, she was an avid rider and competitor with eventing and show jumping, until she got hooked on dressage in the late 1980’s. She has competed on horses she’s owned and trained all the way from training level to Grand Prix.
Briggs, K. 1997. Cushing’s Disease Diagnosis. TheHorse.com
Kentucky Equine Research. 2019. What Do We Really Know About Pergolide for Equine Cushing’s? ker.com
Reisinger, N., Schaumberger, S., Nagl, V., Hessenberger, S., & Schatzmayr, G., 2014. Milk Thistle Extract and Silymarin Inhibit Lipopolysaccharide Induced Lamellar Separation of Hoof Explants in Vitro. Toxins, 6(10), 2962–2974