This article has not yet been professionally approved. The information is based on the sources listed below.
Cushing's in horses (PPID): what feeding can do
Why PPID remains a veterinary diagnosis, why feeding depends on insulin status and body condition, and what hay analysis, teeth and mineral supply clarify along the way.
The short answer
Cushing's in horses, technically PPID, is an age-related disease that is diagnosed and treated by a vet. Feed does not treat PPID. The ration depends on body condition and on whether insulin dysregulation is also present: in that case, feeds lower in sugar and starch and limited grazing are indicated. With normal insulin status, the guideline states that carbohydrate restriction is not needed 1.
What is Cushing's in horses – and what can feeding do?
PPID (Pituitary Pars Intermedia Dysfunction), commonly called Cushing's, is a slowly progressing, age-related disease: nerve cells in the hypothalamus degenerate, and part of the pituitary gland releases increased amounts of hormones such as ACTH. Prevalence rises with age and, according to the guideline, reaches about 20% in equids over 15 years and 30% in animals over 30 years 1.
Diagnosis and treatment are veterinary tasks. The guideline describes daily medication as the basis of treatment, combined with suitable feeding management and general preventive healthcare 1. Feeding therefore does not treat PPID. It adapts the ration to body condition and metabolic status. There is so far no proof of efficacy for complementary feeds to treat PPID 1.
Why does insulin status decide about sugar and starch?
PPID is often accompanied by insulin dysregulation; the guideline therefore recommends assessing insulin status together with PPID 1. The EMS recommendations of the same expert group report insulin dysregulation in about 30% of PPID horses and advise testing horses over ten years of age for both disorders 2.
For feeding, this is the decisive difference. Non-structural carbohydrates (NSC), i.e. sugar, fructan and starch, are the most important trigger of insulin release 2. Horses with PPID and insulin dysregulation therefore need feeds lower in NSC and limited access to pasture. According to the guideline, PPID horses with normal insulin status confirmed by testing do not need a carbohydrate-reduced ration 1.
The season plays a part: insulin values tend to be higher in winter. The guideline advises avoiding overfeeding and additional NSC-rich feeds during the winter months 2.
| Starting point | Feeding focus |
|---|---|
| PPID, normal insulin status, thin or losing muscle | No carbohydrate restriction needed; more fat, protein and energy, e.g. via senior feed, pasture, added fat or lucerne-based feeds 1 |
| PPID with insulin dysregulation | Feeds lower in NSC and limited access to pasture 1 |
| PPID with insulin dysregulation and overweight | Additionally reduce energy intake, reduce weight in a controlled and supervised way 2 |
Simplified allocation based on the guideline; your vet decides how your horse is classified.
Which hay values do you need – and what does hay analysis show?
For horses with insulin dysregulation, the specialist guidelines recommend hay with less than 10% NSC 23. NSC is calculated as the sum of water-soluble carbohydrates and starch. Older calculation methods by difference, reported as NFC, include other components with no effect on insulin and are no longer recommended for this purpose 2.
So check what your lab report actually contains. In the laboratory order form reviewed, the hay nutrient package includes sugar, fructan and NFC among other things; starch is a separate additional test 4. When comparing values, also check whether a value refers to as-fed or dry matter 5.
Soaking can lower the sugar content, but not reliably: in one study, the mean loss was 27% with a range of 6 to 54% 6. At the same time, minerals are lost 7. Analysed hay is therefore a more reliable basis than an estimated soaking effect.
- Sample the hay batch you are actually feeding and assign the lab results to that batch.
- Note sugar, fructan and starch with unit and reference basis.
- Do not use NFC as the NSC value.
- When the batch changes, do not simply keep using the old results.
How do you feed an older PPID horse that is losing condition?
Many horses with PPID are thin or lose muscle. According to the guideline, they may benefit from more fat, protein and energy, for example via high-quality senior feed, grazing, added fat or lucerne-based feeds, provided their insulin status allows it 1. If insulin dysregulation is also present, the EMS recommendations for thin horses provide for a low-NSC ration that supplies additional energy via fat and high-quality fibre, with access to pasture still limited 2.
The requirements of older horses can change over time. The guideline therefore recommends that owners check body condition frequently 1. The body condition score assesses fat reserves using visible and palpable features and complements body weight 8.
Teeth are part of it too: the guideline highlights dental care alongside hoof care and parasite control 1. If a horse can no longer chew long-stem hay well, chopped forage, cubes or pellets are considered a substitute. Soaked, they reduce the risk of choke in some horses 9.
Does a horse with Cushing's need special minerals or supplements?
A special PPID mineral mix cannot be derived from the guidelines reviewed. There is no proof of efficacy for complementary feeds to treat PPID 1. For magnesium and chromium, the EMS consensus describes isolated indications of improved insulin regulation that other studies have not confirmed 3. This is not evidence of an effect in PPID.
The basic supply still has to be right. If the ration is restricted or the hay is soaked, protein, minerals and vitamins can run short. These nutrients should then be balanced in a targeted way 3, according to the guideline with a low-sugar mineral, vitamin and protein supplement 2.
To do this, calculate the total ration: hay, pasture, concentrates and all supplements together. Only the balance against requirements shows whether there is a gap or whether another product would lead to double supply 5.
What should you discuss with your vet?
PPID needs long-term management. The expert group recommends re-testing older horses regularly for insulin status and PPID, because age and PPID can worsen insulin dysregulation 2. Good records make feeding decisions easier to follow.
- ACTH and insulin test results with dates, because the season affects interpretation 1.
- Trend in weight and body condition score.
- Hay analysis with batch reference and daily hay amount.
- Grazing times and pasture condition.
- All other feeds, treats and supplements with daily amounts.
- Findings from dental and hoof checks.
Key takeaways
- Diagnosis and treatment belong in your vet's hands; there is no proof of efficacy for complementary feed in PPID 1.
- Whether the ration needs to be low in sugar and starch is decided by the tested insulin status, not by the PPID diagnosis alone 12.
- Many horses with PPID are thin or lose muscle; check body condition regularly 1.
Frequently asked questions
What can a horse with Cushing's eat?
That depends on body condition and insulin status. According to the guideline, horses with PPID and insulin dysregulation need feeds lower in NSC and limited access to pasture. Thin horses with normal insulin status, on the other hand, may benefit from more fat, protein and energy 1. Insulin status is clarified by a veterinary test.
Does every horse with Cushing's need low-sugar hay?
No. The guideline states that PPID horses with normal insulin status confirmed by a dynamic test do not need a carbohydrate-reduced ration 1. If insulin dysregulation is present, hay with less than 10% NSC is recommended 2.
What is the evidence for herbs such as chasteberry in PPID?
According to the veterinary guideline, there is so far no scientific proof of efficacy for complementary feeds to treat PPID 1. Treatment is decided by your vet.
How long does a horse with Cushing's live?
There is no general figure. According to the guideline, most owners report a good quality of life for their PPID horses, and the disease does not necessarily shorten life expectancy. Because most affected animals are old, other age-related diseases remain an issue 1.
Sources & studies
The content is based on the references listed below. It does not replace individual veterinary or feeding advice.
Show list of sources (9)
- Hart K, Bamford N, Bertin FR, Durham A, Frank N, McGowan C, Schott H (Equine Endocrinology Group, 2025): Recommendations for the Diagnosis and Management of Pituitary Pars Intermedia Dysfunction (PPID). Revised October 2025Veterinary expert recommendation, checked on 30 September 2026. Summary: age-related, slowly progressive disease; prevalence 20% in equids over 15 years, 30% in those over 30 years; hypertrichosis as the classic sign; diagnosis via ACTH, to be interpreted according to season; treatment with daily medication plus feeding management and wellness care. Table 1: clinical spectrum (incl. muscle wasting, polyuria/polydipsia, recurrent infections, HAL). Table 4: choice of feed by body condition and insulin status; with normal insulin status (dynamic test) no carbohydrate restriction needed; many PPID horses lean or with muscle wasting – more fat, protein and energy; frequent BCS checks; dental care, hoof care, parasite control; good quality of life, life expectancy not necessarily shortened. Table 5: efficacy of complementary feeds in PPID not scientifically demonstrated. Recommendation for vets, not a guide for owners.
- Bertin FR, Bailey S, Burns T, de Laat M, Durham A, Frank N, Kritchevsky J, Menzies-Gow N (Equine Endocrinology Group, 2024): Recommendations for the Diagnosis and Management of Equine Metabolic Syndrome (EMS) and Insulin Dysregulation. Revised June 2024Veterinary expert recommendation, checked on 30 September 2026. Table 1: HAL is by far the most common form of laminitis at over 90%; NSC = water-soluble carbohydrates plus starch, NFC subtraction formulas no longer recommended; NSC as the main trigger of insulin release. Risk factors: NSC-rich ration, age, PPID; overweight aggravating but not consistently. Table 5: hay < 10% NSC; for weight loss 1.5% of body mass as dry matter (1.7% as fed), check every 30 days, lower limit 1.2%; avoid stress because of the risk of hyperlipaemia; straw up to approx. 50% introduced gradually; soak hay in cold water for ≥ 60 min if NSC > 10% or not analysed; hay net/small meals; low-sugar mineral/vitamin/protein balancer; restrict grazing, resume only after laminitis has subsided and an insulin test; pasture NSC varies with temperature, light, rainfall, fertilisation; higher insulin values in winter; exercise only without active laminitis. FAQ: insulin dysregulation in about 30% of PPID horses; test for PPID and ID from 10 years of age. Recommendation for vets, not a guide for owners.
- Durham AE et al. (2019): ECEIM consensus statement on equine metabolic syndrome. Journal of Veterinary Internal Medicine 33:335–349Sections 2–3 and 7: overweight is not an EMS diagnosis; ration adjustment, monitoring and exercise in at-risk horses must be supervised by a vet. Clinical restriction protocols are not adopted as a general recommendation for owners.
- LUFA Nord-West: Untersuchungsauftrag Pferdefutter 2026/27p. 1: analysis packages and prices per sample plus VAT; p. 2: scope of analysis, sample quantities and shipping. Prices for 2026/27, checked on 28 September 2026; not an Equivora offer.
- Bayerische Landesanstalt für Landwirtschaft (LfL): Gruber Tabelle zur PferdefütterungPractical reference table with requirement and feed values based on the GfE recommendations; the basis of many ration calculations in German-speaking countries. Chapter 9.3, Table 39: most common poisonous plants for horses with habitat, toxicity and risk level (after Kamphues et al. 2014)
- Longland AC, Ince J, Harris PA (2011): Effects of soaking on the water-soluble carbohydrate and crude protein content of hay. Veterinary Record 168(23):618Soaking (up to 16 h, ~8 °C) reduces water-soluble carbohydrates by 27% on average (range 6–54%, fructan ~24%), crude protein remains statistically unchanged
- Martinson K, Jung H, Hathaway M, Sheaffer C (2012): The effect of soaking on protein and mineral loss in Orchardgrass and Alfalfa hay. Journal of Equine Veterinary Science 32(12):776–782Soaking (15–60 min or 12 h) reduces potassium (up to 80%), phosphorus (up to 65%) and magnesium (up to 45%) depending on duration/temperature; effect on crude protein inconsistent/small
- Henneke DR, Potter GD, Kreider JL, Yeates BF (1983): Relationship between condition score, physical measurements and body fat percentage in mares. Equine Veterinary Journal 15(4):371–372Original publication on the body condition score; bibliographically checked. Its application and limits are additionally supported by horse-specific specialist reviews.
- Liburt NR (2026): Feeding Practices in Horses and Other Equids. Merck Veterinary ManualSpecialist overview, as of February 2026: forage basis, concentrates as required, bran/mash and Ca:P balance, gradual feed changes. No efficacy study on commercial mash products.