Grass plants, through the process of photosynthesis produce simple sugars (carbohydrate) to create an energy source for the plant. When sugars are produced in excess of the energy requirement of the plant for growth and development, they are converted into storage, or ‘‘reserve’’ carbohydrates.
Pasture grass in the UK accumulate fructan as their reserve carbohydrate, which is stored in the stem of the plant, until required as an energy source. Therefore short, stemmy, tightly grazed pastures are likely to have an increased fructan content.
The grass plant requires a number of nutrients to develop and grow. Applying controlled amounts of fertiliser will encourage the plant to grow effectively. If the plant has insufficient nutrient levels to aid growth the fructan is stored, as opposed to being used throughout the plant to aid growth.
Cold, frosty mornings are a particular time when fructan content can be extremely high. The sunshine is still causing the plant to photosynthesise and produce carbohydrate. However, because of the cold temperatures the plant will not be actively growing, causing the plant to store the fructan as reserve carbohydrate. Grazing horses during frosty mornings should be avoided for these reasons.
The fructan content of grass can change from day to day and even within a single day. Light, temperature, water availability and the species of grass are all factors, which will affect both the production rate and use of fructan by the grass.
GRASS MANAGEMENT TIPS
- Apply sufficient fertiliser to keep the grass plant healthy. This should be done after a soil analysis to determine nutrient availability.
- During high growth periods monitor grass intake carefully, and restrict grazing if necessary by strip grazing.
- Don’t turnout on frosty grass, particularly on a sunny morning, when fructan levels can soar.
- When applying grass seed select low fructan grass species, specifically designed for equestrian pastures. Do not use agricultural grass mixtures which are high in fructan.