Don’t overlook magnesium supplements this spring

The prolonged cold and wet winter weather has led to restricted grass growth, delayed turnout on many farms, and in some cases shortages of forage earmarked for buffer feeding.

However, as grass growth catches up and producers look to make the most of spring grass, they are being reminded not to overlook the potentially fatal consequences of magnesium deficiency that results in staggers.

Bronwen Pihlwret, QLF’s nutritional adviser, explains why cows may still be at risk this spring, despite the later calendar date for turnout.

“Cows rely heavily on diet to ensure a sufficient supply of magnesium, and as lush spring grass is naturally low in the mineral, buffering, or restricting access to lush grass, can help reduce the danger of cows getting staggers.

Bronwen Pihlwret.

“It’s important to understand that the risk is likely to continue until average temperatures reach 15-16ºC, and grass reaches maturity, both of which show every sign of coming late this year.

“For this reason, it’s likely that supplementation of magnesium may be required for longer periods than normal this spring, particularly in situations where mineralised concentrate feeding is reduced.”

Bronwen adds that spring grass is also typically low in structural NDF, and while this promotes DMI’s and subsequently milk yields, it reduces the opportunity for mineral absorption.

“Because fresh grass has a low structural fibre content, it passes through the rumen much quicker reducing the opportunity for any magnesium in feed to be absorbed across the rumen wall. In combination with low magnesium levels this further increases the risk of staggers,” she says.

“So, to help reduce this, it’s vital that producers include a magnesium supplement before and during turnout to help minimise a dip in productivity, and at worst death of livestock.

“It can be tempting to cut inputs, especially when the milk price drops, but it’s key to provide a magnesium supplement at grass as staggers can come on very quickly and swift veterinary assistance is vital to avoid death.”

Traditionally, producers may have added magnesium chloride flakes to water troughs, but Bronwen advises against this as it can make the water undesirable, reduce water intakes, and in turn restrict milk yield.

For this reason, she suggests that providing a palatable source of the mineral in the diet is the most effective way of achieving sufficient uptake.

“Providing a palatable source of magnesium in solution, such as QLF’s Spring Mag (2% magnesium), fed through liquid lick feeders in the field is a good option this spring as cows can access it ad-lib, and it doesn’t require any additional inputs.

“As staggers can often prove fatal if not treated in time, it’s extremely important not to overlook magnesium supplementation at turnout, or you could run the risk of heavy losses,” she concludes.