With record winter rainfall leaching minerals from the soil and potassium being more aggressive on magnesium than previously thought, farmers are being urged to guard against a potentially greater threat from grass staggers this spring.
“We can’t yet be sure how much of an effect the tremendously wet winter has had on soil mineral levels, but we do know that magnesium deficiency is always a significant threat at turnout. What’s more, relatively recent research now shows just how antagonistic potassium is to magnesium – so much so that we now know that cows need an extra 18g per day of magnesium for every 1% potassium in forage over and above a base level of 1%. And mineral forage reports at the end of the 2013 grazing season were reporting very high potassium levels at 2.89%,” says Rumenco technical manager David Thornton.
He adds that these recommendations are based on average pasture potassium levels and on many farms levels of this aggressive mineral may be much higher.
“I know we say it every year, but farmers turning out cattle really can’t afford to be complacent with their magnesium supplementation. The staggers threat is very real and arguably greater than ever this spring.”
Rumenco says staggers prevention strategies must combine best practice stock management with effective magnesium supplementation.
“It’s vital that livestock have access to long fibre, as well as the lush grass they encounter at turnout. This prevents low dry matter spring grass passing through the rumen too quickly without enough of an opportunity for the animal to absorb magnesium. In addition, consider offering a suitable salt source – this will help maintain a high sodium:potassium ratio, which will improve magnesium absorption,” David Thornton says.
“Effective magnesium supplementation is crucial,” he adds. “A variety of mineral carrier options are available to farmers, but remember to be wary of suppliers claiming that multiple sources of magnesium in a supplement are better than a sole source of the mineral.
“There are a number of different magnesium sources used by supplement manufacturers in their products, and some stress the importance of including a variety to boost availability of the mineral to the animal. But in fact magnesium availability is pretty similar across all the various common sources and true absorption in the animal is directly related to the magnesium content of the source, not its availability.
“However, particle size in a magnesium source is important though. For example, when you compare the two magnesium oxide (Cal Mag) sources – in granular and powder form – the powdered Cal Mag delivers a higher magnesium absorption in the animal. And this is the source we use in the Supalyx Mag bucket, for example,” David Thornton says.
“Molassed, weatherproof buckets and blocks supplemented with the right source of magnesium offer the most hassle-free way of ensuring stock get the mineral they need. No troughs are needed and these types of supplements are available 24/7. They also prevent bullying and save feeding time and labour – and regular trips over already muddy land. Bear in mind too that magnesium is not very palatable, so being molassed, bucket and block products do help maintain the necessary intakes of this essential mineral.”
