This article has not yet been professionally approved. The information is based on the sources listed below.
Overweight horses: assessing the ration and forage
Document body condition and feed intake in a traceable way, check additional energy sources and have feeding changes supported by a specialist.
The short answer
If body condition is too high, actual feed intake, energy supply and the trend over time need to be considered together. Body weight and fat deposits are different measures. Overweight alone does not prove EMS; with a history of laminitis, unclear fat deposits or health concerns, a veterinary investigation is needed 12.
How can you tell that a professional assessment is needed?
A high weighbridge weight cannot by itself describe the proportion of fat. Build and size are part of the assessment; the body condition score evaluates body condition using features you can see and feel 1. So document weight and body condition separately.
The EMS consensus statement distinguishes overweight from insulin dysregulation: there are animals with fat deposits without EMS and animals with EMS without marked overweight. A diagnosis requires a veterinary assessment and appropriate tests 2.
Which feed data should you collect first?
An energy surplus relative to requirements favours excessive body condition 3. The practical stocktake should therefore also include small, frequently forgotten amounts of feed. Record several ordinary days and discuss the uncertainty if grazing intake or group feeding cannot be measured individually.
- Document types of forage, weighed quantities and leftovers.
- Note grazing times, grass growth and access to shared feed.
- Record concentrates, mash, oil, treats and supplements with daily quantities.
- Record work, changes in management and the weight trend so far.
Why is simply feeding less hay not general guidance?
Besides its nutritional function, forage fulfils important roles in feeding. The Gruber Table therefore treats forage quantity and feeding management as integral parts of ration planning 4. Any adjustment of energy must take these requirements into account.
Clinical weight-loss programmes in the EMS consensus statement include monitoring and individual adjustment. They are not adopted here as a general formula for cutting hay. Have quantity, choice of feed and approach planned by a professional; an online calculation does not replace this support 2.
Does an overweight horse still need complementary feed?
A lower intended energy supply does not automatically mean that every other nutrient is sufficiently provided. Mineral supply and energy are considered separately in the ration assessment 5. Check existing products and avoid additional energy or duplicated supplements without a reason in the ration.
- Which products are mainly additional sources of energy?
- Which declared minerals are already being supplied?
- Which values are actually measured, and which only estimated?
- Which decision does the specialist need to make with you?
How do you record progress and open risks?
Weight, body condition and the agreed feeding should be monitored together over time. The EMS consensus statement emphasises long-term cooperation with the vet and appropriate exercise management; an exercise plan must be tailored individually, especially in the case of laminitis 2.
- Agree the timing and method of monitoring with the specialist.
- Compare repeated measurements taken under similar conditions.
- Note every change to pasture, forage or concentrates.
- In the case of pain, refusal to eat or rapid unexplained weight change, have your vet investigate.
Key takeaways
Frequently asked questions
Does a fat horse automatically have EMS?
No. Overweight and EMS are not the same thing. The diagnosis is made on the basis of a veterinary assessment and suitable tests 2.
Should I simply halve the amount of hay?
This article does not recommend a general cut in forage. Energy adjustment and an adequate forage supply must be planned together 4.
Can a ration analysis replace a veterinary plan?
No. A calculation compares feed data against reference requirements. It is not a diagnosis and not an individual treatment; risk cases need veterinary support.
Sources & studies
The content is based on the references listed below. It does not replace individual veterinary or feeding advice.
Show list of sources (5)
- 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.
- 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.
- Liburt NR (2026): Nutritional Diseases of Horses and Other Equids. Merck Veterinary ManualSpecialist overview, as of February 2026: energy surplus, non-specific signs of deficiency and risks of oversupplementation; no basis for a remote diagnosis.
- 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)
- Merck Veterinary Manual: Nutritional Requirements of Horses and Other EquidsSummary of the NRC recommendations: water requirement 5 litres per 100 kg body mass per day at maintenance, sweat losses of around 3.1 g sodium, 5.3 g chloride and 1.6 g potassium per litre, salt recommendation 1.6–1.8 g per kg feed dry matter at a maximum of 6% of the ration; from a 50% forage share potassium is adequately covered. Also covers the selenium requirement (0.1 mg/kg feed dry matter or at least 1 mg/day for a 500 kg horse, selenium as a component of glutathione peroxidase together with vitamin E) and the strong location-dependent variation of selenium in forage (grass forage on average 0.194 ppm, range 0–1.2 ppm); some regions are markedly low in selenium and may need supplementation. Also gives the iodine requirement (0.35 mg/kg feed dry matter, mares in late pregnancy 0.4), iodine poisoning of pregnant mares from around 40 mg/day, documented goitre cases in mares and their foals associated with large amounts of dried seaweed (kelp), that iodised salt easily covers the requirement, and that iodine supplementation is usually unnecessary except in severely iodine-deficient regions