Grass tetany: Are your suckler cows at risk?

The majority of suckler herds are still out on land grazing and farmers must now turn their attention to the risks associated with grass tetany in the weeks coming up to housing.

Grass tetany is caused by a magnesium (Mg) deficiency, which can occur when animals are grazing heavy, lush, low-fibre paddocks. Cows are most at risk in paddocks which have received heavy dressings of nitrogen (N).

The deficiency can effect both suckler and dairy cows and farmers must take extra care in paddocks with high levels of potassium (K) and N.

Symptoms and treatment of grass tetany

Grass tetany is one of the most common causes of sudden death in suckler cows during the grazing season.

Symptoms include:

  • Hyperness;
  • Frothing at the mouth;
  • Staggering;
  • Body tremors;
  • Visual distress;
  • Death.

Time is of the essence when it comes to grass tetany. In cases where a cow is suffering and treatment is not carried out in a short space of time, it is likely that the cow will not survive.

Where farmers have identified the disease, a vet should be called immediately. The treatment involves the administration of magnesium sulphate.

Like the majority of diseases, prevention is better than cure and there are many measures that farmers can put in place to reduce the risk of grass tetany.

If concerned, farmers should offer supplementary magnesium to their suckler cows. This can be done using lick buckets. However, if using lick buckets, ensure vulnerable cows are coming forward to avail of the supplementation.

Alternatively, feeding concentrates containing Mg is another option or, administering a magnesium bolus to cows.

Another option which is more effective but perhaps less feasible on smaller suckler farms is pasture dusting with Mg or supplementing Mg in the water supply.

However, farmers must take care when it comes to offering mineral buckets, as some cows are more likely to consume the ‘lick’ than others.

Feeding straw or hay can also be used to reduce the risk of grass tetany as this slows down the digestion process and allows more Mg to be absorbed from the diet.

With the grazing season drawing to a close, suckler farmers should keep an eye on cows to ensure grass tetany does not impact their suckler herd and cows come off grass and into the shed in a fit, healthy condition in the coming weeks.