Turning stock out to grass in spring comes as a relief to many farmers. However, animal performance and health suffer when livestock do not maintain a nutritionally balanced diet. Fast-growing and lush grass in early season is often low in minerals and lacking magnesium. When cattle are turned out to graze, they risk developing grass staggers (tetany/hypomagnesaemia). This is a serious metabolic disorder and a very real threat for suckler and dairy cows at turnout. Ewes post-lambing are also at risk.
However, it can be managed by assessing and managing the on-farm risks.
What is Grass Staggers?
Estimations suggest that 1% of cattle in the UK will experience clinical grass staggers (ADHB). However a far larger percentage of animals, including ewes, will experience sub-clinical cases that may affect overall animal performance.
Magnesium (Mg) is a a key macro-nutrient in the diet. It is especially important to ensure correct nerve and muscle function, as well as bone formation, it also acts as an aid to fibre digestion in the rumen. A deficiency of available dietary magnesium significantly increases the risk of developing clinical or subclinical hypocalcaemia (milk fever).
The Causes Of Grass Staggers
Cows are almost entirely dependent on a continual daily dietary intake of Magnesium (Mg) as there is only a small available pool of mineral internally to cover shortfalls. A lack of dietary supply and/or intake of Mg (low dry matter intake) will, therefore, lead to the development of grass staggers.
Rapidly growing spring grass typically has a low magnesium content (0.1 to 0.2%) in dry matter. Combined with its low dry matter and rapid transit through the rumen, this can result in very low levels of magnesium absorption into the bloodstream. In the most part, animal’s bones store magnesium, making it unavailable when dietary supply is compromised. During high-risk periods, livestock depend on daily magnesium supplementation to maintain adequate blood magnesium levels.
How To Prevent Grass Staggers
To help alleviate the risk of grass staggers long fibre should always be available in the form of hay or silage, to help slow the transition of wet spring grass through the rumen. It is also essential to maintain dietary energy levels (notably starch and sugar) to help prevent excess rumen ammonia.
Most importantly, it is vital to ensure stock have daily access to a suitable magnesium supplement. Farmers can ensure their stock has a reliable magnesium supplement to complement their diet by presenting magnesium, typically an unpalatable mineral, in a molasses free-access lick. To better prepare stock for changes, farmers should offer magnesium supplements up to two weeks before turnout.
Choosing a magnesium supplement for cows this spring
There are 3 key criteria for an effective magnesium supplement:
- The magnesium level in the formulation
- The palatability and therefore the intake realistically achievable*, and
- How bio-available the magnesium is to the cow (some magnesium sources are absorbed into the bloodstream better than others )
* This is particularly important when the supplementary magnesium is free access and consumed by choice.
Crystalyx Cattle High-Mag contains 10.5% magnesium and uses dehydrated molasses to ensure palatability and intakes, even on lush spring grass.
- Contains 35% sugar to ensure palatability, even when livestock are grazing on lush grass.
- Supplies multiple magnesium sources to optimise magnesium availability and help maintain normal blood magnesium levels
- Provides all essential minerals, trace elements and vitamins needed to balance spring and autumn pasture
Research at Glasgow University (School of Veterinary Medicine) has confirmed that the high-digestibility and availability of the magnesium sources used in Crystalyx Cattle High-Mag ensures that normal blood magnesium levels are maintained when target intakes are achieved.
Got Any Questions?
Our team of livestock experts at Crystalyx are here to help and can answer any questions you may have.