The main reason for moving away from cereals is their high starch content. Starch is a carbohydrate that is a fast source of energy, but it can cause a range of health problems. The horse’s digestive system is not adapted to digesting large amounts of starch and simple sugars. Too much of them can lead to gastric ulcers, laminitis, fermentative colic, metabolic problems (insulin resistance, Cushing’s syndrome) and also to behavioural disturbances such as excitability and difficulty concentrating in work. In recent years many studies have been published showing a link between a diet rich in non-structural carbohydrates and the development of diseases that, not long ago, were thought to be unrelated to feeding.
For years, oats were regarded as the safest cereal for horses. The starch they contain has a loose structure, which makes it easier to digest in the small intestine. Even so, the easy availability of energy from oats is often linked to horses becoming over-excited, especially nervous, young or sport horses. Many owners notice that once oats are taken out, their horses become calmer, concentrate better and are easier to work with. Barley is a cereal with a higher energy value than oats, but its starch is harder to digest, which increases the risk of fermentation further along the digestive tract. That is why it needs prior processing called micronising. Maize, in turn, is the cereal with the highest calorie content, but on the other hand it is the hardest to digest. The starch it contains is very concentrated, and if it is unprocessed it can seriously disturb the balance of the horse’s gut microflora. Maize often contributes to metabolic and digestive problems, especially in sensitive horses, horses with ulcers, or horses with a history of laminitis.
The greatest benefit from limiting or completely excluding cereals is seen in horses with gastric ulcers, a tendency to colic and metabolic disorders. It is also a very good step for horses after laminitis or with a tendency to relapse, and for nervous, excitable horses or those that tolerate energy from carbohydrates poorly. In such cases energy can be supplied in another form, for example from vegetable fats such as linseed oil or maize oil, from the structural fibre present in sugar beet pulp, lucerne, hay and haylage, and also from ready-made cereal-free or low-starch feeds.
This does not mean, however, that every horse should be on a cereal-free diet. Some horses do well on a small amount of cereals, especially if they are in hard work and show no negative signs. The key is an individual approach and watching carefully how the horse responds to a particular diet. Oats, barley and maize are not evil incarnate, but they are not essential ingredients either. Their presence in the ration has to be thought through, balanced and matched to the needs of the individual horse.
To sum up… a diet without cereals is not a passing fashion, but a response to the real needs of a growing number of horses. Cereal starch can be useful, but it often does more harm than good, especially in sensitive, ill or stressed horses. Giving up oats, barley and maize does not mean a lack of energy, but a change to a source that is safer and better suited to the way horses function.