Grassland Blog June-July 2024

Grass staggers will be a worry for farmers at this time of year with an estimated 1% of cattle in the UK experiencing grass staggers and many more suffering symptoms. The outcome for those that do get it is potentially fatal so prevention through prescription nutrition is the best cure this season.

Also known as hypomagnesaemia, grass staggers occurs when animals are deficient in magnesium. It is most common in lactating cows that lose magnesium during milking and are fed grass or forage with a low magnesium content. Spotting animal behaviour symptoms early, including restlessness, teeth grinding, an excitable nature, and separation from the main group, will be key to stopping it.

Although we can’t control losing magnesium through milk, we can support grass nutrition to offer cows improved ways to replenish magnesium levels.

Magnesium is directly involved with photosynthesis and is essential for plant growth and sugar production, whilst its presence activates several chemical reactions which provide animals with energy to move and grow. If soils have good levels of magnesium, then maintenance applications will be sufficient each year, as the nutrient binds to clay particles and isn’t prone to leaching.

We also need to be aware of the relationship magnesium has with another key nutrient – potassium. High levels of potassium within an animal’s diet can reduce magnesium absorption into the blood, leading to grass staggers.

The ratio of potassium to magnesium needs to be below 20:1, and ideally less than 10:1, to ensure it is available to livestock. The easiest way to check these levels is by analysing fresh grass and silage, and grass nutrition requirements can then be assessed for following applications.

Sufficient levels of sodium also play a key role as it helps improve magnesium absorption and mineral balances in the forage. Good sodium levels improve forage palatability, allowing animals to increase dry matter uptake through tighter grazing. We recommend applying 10-12kg/ha of sodium with each fertiliser application.

To ensure the right levels are being applied to your crops, meet one of our regional nutrition agronomists on your farm.

Find your regional nutrition agronomist: Meet the Team – Origin Fertilisers