In the past, wild horses were used to feeding on barren meadows with dry bushes. The fields we keep our horses on today are nothing like those of 200 years ago. Today’s high-performance dairy farming has resulted in the cultivation of grass varieties that are rich in energy, protein and sugar, which are optimal for cows but unsuitable for horses. Therefore, we should keep an eye on the fructan content of the grass to prevent diseases like laminitis.
What is fructan?
Fructan is a long-chain carbohydrate that serves the plant as a storage for excess energy. It is produced during photosynthesis. This is the case, for example, when it is sunny but temperatures are low, so that the energy gained is not used directly for growing and is therefore stored for the time being.
Why is fructan in issue?
Fructans are metabolized in the large intestine by bacteria and are rapidly fermentable. A large intake can lead to a shift in the intestinal flora. The carbohydrate-splitting bacteria increase to the detriment of the crude fiber-splitting bacteria. They die and release endotoxins, which enter the bloodstream via the damaged intestinal wall.
In the hoof corium, the toxins lead to small blood clots which impair the blood circulation. This process can lead to the development of laminitis. It was long thought that protein was the trigger for feeding-induced laminitis, but this assumption is now outdated. Of course, the development of laminitis is related to other factors such as previous illnesses, poor hoof condition, or feeding that is generally too high in carbohydrates. In addition, it is discussed to what extent mold toxins (endophytes) living in symbiosis with grasses have an influence.
When's the fructan-risk particularly high?
Basically, when the grass can not grow, it stores more fructan. This is the case, for example, when it is too cold or too dry.
In May and in October and November the highest levels of fructan are measured, as the grass is less able to grow at this time. In August and September, on the other hand, the fructan content in the grass is usually at its lowest.
In her dissertation in 2002, Sandra Dahlhoff found that the fructan content depends strongly on the average temperature of the past 48 hours. If the temperature increases, the fructan content decreases. In addition, the fructan content in the grass is mainly related to the average temperature during the night. If it was colder than 8°C, the risk of high fructan content is usually higher. If the previous night was rather warm, the risk is somewhat lower, unless it was dry for a long time. Again: Whenever the grass grows, the fructan content decreases.
Especially critical: sun and frosty temperatures
The following situation is particularly problematic: a lot of sun and frosty or cold weather. Photosynthesis can take place here, but the energy produced is not converted into growth.
A popular belief among horse owners is that short mown grass is particularly high in fructan because it can hardly grow and therefore accumulates fructan. This is only partly correct, as regularly mowing the meadows to about 15 cm, can help reduce the sugar content in the grass.
The HorseAnalytics App
How can fertilizing help?
It may sound surprising: Applying nitrogenous fertilizer in spring also helps combat high fructan concentrations, since today’s high-sugar, high-performance grass, such as German ryegrass or meadow fescue, can only grow well in nutrient-rich soils. If the nutrients are lacking, the plant is stressed and produces fructan.
The roughage may also be of concern.
Roughage also contains fructan. Thus, up to 80% of the fructan from the grass can end up in the hay. Special care should be taken with the first cut and the second cut. Washing the hay in warm water will flush the sugars out of the hay. The rule here is to let it soak for at least 30 minutes. But be careful: at the same time bacteria can multiply explosively!
Which types of grass are particularly rich in fructan?
German ryegrass and meadow fescue are considered to be particularly rich in fructan. Fructan is mostly stored in the stem. In contrast, timothy, red fescue, meadow foxtail and cocksfoot are low in fructan. Typically, a mixture of the different grass species is found in German pastures.
How can HorseAnalytics help?
Our HorseAnalytics app helps you by displaying the fructan risk at your horse’s location using a traffic light system. The app processes the weather data at your horse’s location and thus provides forecasts. This is an enormous relief, especially for horses with EMS or Cushing’s disease.