This article has not yet been professionally approved. The information is based on the sources listed below.
Wheat bran for horses: benefits, phosphorus and amount
Wheat bran is high in fibre and binds a lot of water, but it also brings a lot of phosphorus and little calcium. What that means for the ration and why bran is not a laxative.
The short answer
Wheat bran consists of the outer layers of the grain. It provides fibre, binds a lot of water and contains B vitamins, magnesium, iron and zinc 1. At the same time, it brings a lot of phosphorus and little calcium, which shifts the Ca:P of the ration 2. According to the specialist review, bran is not a laxative; large, irregular feeds are more likely to upset digestion.
What wheat bran is
Bran is produced in the mill: it is the outer layers separated from the flour. Brans provide fibre, have a high water-binding capacity and contain B vitamins, magnesium, iron and zinc 1. Because substances clinging to the husk end up in the bran in greater amounts, you should pay particular attention to its microbiological quality for sensitive horses.
The phosphorus problem
Bran brings a lot of phosphorus and little calcium 2. Grass hay usually has a favourable ratio on its own; rations rich in cereals and bran tip it off balance 34. For adult horses, the Gruber Table gives a Ca:P of 1.5 to 2 to 1 as a guideline 1.
Bran mash and the laxative idea
Bran is often fed as a mash and as a remedy for digestive problems. The specialist review does not consider the laxative idea supported and warns of digestive upsets after large, irregular feeds of bran 2. If there are digestive problems, a veterinary assessment comes first.
Key takeaways
Frequently asked questions
Does wheat bran have a laxative effect?
According to the specialist review, the widespread laxative idea is not supported. Larger, irregular feeds of bran are more likely to trigger digestive upsets after an abrupt change 2.
How do I balance the phosphorus from bran?
By calculating the Ca:P of the whole ration. For adult horses, a ratio of 1.5 to 2 to 1 serves as a guide 15. If calcium is lacking, a suitable mineral feed or calcium-rich forage can restore the balance.
Does a bran mash once a week make sense?
An occasional, large mash is a sudden change for the digestive system. If you feed bran, it is better to do so regularly in small amounts and with an eye on the whole ration 2.
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)
- 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)
- 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.
- NRC – Nutrient Requirements of Horses, 6th ed.International reference for the nutrient requirements of horses (National Research Council)
- Coenen M, Vervuert I (2020): Pferdefütterung. Begründet von H. Meyer. 6., aktualisierte Aufl., Georg Thieme Verlag, Stuttgart. ISBN 978-3-13-241778-6Standard reference work on equine nutrition in German-speaking countries; Table 4.17 mineral recommendations (recommended supply and minimum requirement), Table 4.18 derived sweat volumes per work level and weight class, Table 4.19 electrolyte performance requirement per sweat volume (in addition to maintenance requirement)
- GfE (2014) – Empfehlungen zur Energie- und Nährstoffversorgung von PferdenSpecialist reference in German-speaking countries (GfE, German Society of Nutrition Physiology), Committee for Requirement Standards