Supplementing rations with magnesium may be vital this spring

Supplementing rations with magnesium may be vital this spring
21 Mar 2018

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 can result in staggers.  

Magnesium supply

Cows may still be at risk this spring, despite the later calendar date for turnout. So says QLF’s Bronwen Pihlwret. “Cows rely heavily on diet to ensure a sufficient supply of magnesium and because lush spring grass is naturally low in the mineral then buffering, or restricting access to this grass, can help to reduce the danger of grass staggers.

“It’s important to understand that the risk is likely to continue until average temperatures reach between 15ºC and 16ºC, and grass reaches maturity. Both parameters show every sign of coming late than usual this year."

Magnesium supplementation

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

She adds that spring grass is also typically low in structural NDF. While this promotes DMIs and subsequently milk yields, it reduces the opportunity for mineral absorption.

Increased risk of staggers

“Because fresh grass has a low structural-fibre content, it passes through the rumen much quicker and this reduces the opportunity for any magnesium in the 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.”