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Staggers risk can be mitigated

Farmers are warned to manage potential risks associated with magnesium deficiencies in advance of turnout to avoid cases of staggers and the associated performance losses.  

Grass staggers is a very real threat for suckler and dairy cows at turnout, and something that is easily mitigated by assessing and managing the on-farm risks, explains David Thornton, Rumenco technical manager. 

“It’s estimated that 1% of cattle in the UK will experience clinical grass staggers. However, a far larger percentage will experience sub-clinical cases that still affect performance.” 

Generally, sub-clinical symptoms include reduced milk yields, and quality, and a reluctance to be milked or remain with the herd. They can also lead to a supressed dry matter intake, and can predispose cows to milk fever.

“With this in mind, it’s important to build a complete picture of the potential risks on-farm and develop a strategy to alleviate them,” he adds. “By understanding the nutritional challenges; and how your system affects the risk levels to your stock, means grass staggers can be easily be avoided.”

Magnesium is not easily mobilised from stores in the body such as bone, so they rely on their nutrition to maintain adequate blood magnesium levels, which should typically be at around 2 to 3mg per 100ml of blood. 

That’s why nutrition plays such a large role in the development, or avoidance of staggers, explains Mr Thornton. “Lactating dairy cows, and freshly calved beef suckler cows are particularly at risk, especially when their diet hasn't been supplemented for micro-nutrition during the dry period. This, coupled with the fresh lush grass at turnout, leads to a precarious balancing act.

“Rapidly growing spring grass generally has low magnesium content (0.1 to 0.2% in DM). Combined with the added challenge that it has a low dry matter content which leads to it passing through the rumen quicker; this all results in very low levels of magnesium absorption from grazing pastures alone,” he adds.

“Other factors to consider when analysing on-farm risk levels include the impact potassium has on magnesium absorption. 

“Fertiliser directly affects this, with the resulting increased potassium levels producing an upset in the sodium to potassium ratio which, in turn, decreases magnesium absorption in the cow. This is why sodium is an important consideration in the diet at this time in order to readdress this ratio. 

“For every 1% extra potassium in the forage over the base level of 1%, cows need an extra 18g of magnesium in their diet each day. 

Mr Thornton adds that the change in diet, and potential imbalance between protein and carbohydrate at turnout, can affect magnesium absorption levels. “Also, metabolic stresses caused by an imbalance of minerals and trace elements can lead to a ‘lock up’ of magnesium; again impacting the cows ability to draw on the limited supply available. 

“It’s also worth bearing in mind the disease history on-farm for staggers. Once these risks have all been identified, they can be managed accordingly. 

“By providing long fibre sources, such as hay or silage, this can slow the quick transition through the rumen that often happens with spring grass. It’s also vital to ensure stock have access to a magnesium supplement to alleviate the low magnesium levels in spring pastures.

“I’d advise farmers put out Maxx Mag licks six weeks pre turnout to better prepare cattle for the changes. Then, by turnout, the stock are used to the licks, and not faced with a deficit. Magnesium isn’t very palatable, so by presenting it in a molassed, controlled intake lick, farmers can be assured that their stock have a reliable supplement to complement their diet, with typical intakes of around 300g per head per day.”

Mr Thornton concludes that grass staggers is a common, well known challenge at turnout, and something that’s easily avoided on-farm. “By predicting where the main risks are, farmers can avoid any potential production losses.”

Clinical grass staggers is responsible for approximately 1% of total national herd deaths each year 

Normal magnesium level is 2 to 3mg of magnesium per 100ml blood

For every 1% extra potassium in forage, above a 1% base level, cows require an extra 18g per day of magnesium