Risk factors for grass tetany

It’s sensible in any season to anticipate animal health problems that may occur.

At this time of year, grass tetany has the potential to be a significant problem in cattle in this part of Australia.

Since cattle with grass tetany often die suddenly, the first sign of grass tetany on your property may be a deceased cow.

To establish the likelihood of grass tetany occurring on your property, it is worth considering some of the risk factors involved, which can include:

Grazing on immature, rapidly growing, grass dominant pastures;

Soils high in potassium, or with the heavy use of nitrogen or potash fertilisers;

Older, fatter cows soon after calving are most likely to be affected; Low blood magnesium levels in cows; and Cool and cloudy weather. After considering the risk factors it is worth planning how you can prevent, and if necessary treat, an outbreak of grass tetany on your property.

Grass tetany occurs when blood magnesium levels are low. Hence the condition’s other name – hypomagnesaemia. Cattle bodies are unable to store magnesium.

To prevent grass tetany, magnesium supplementation needs to be given daily to cattle at greatest risk during periods of greatest risk.

Have you considered how you could supplement your herd? Whether it is by giving Causmag treated hay, mineral licks, magnesium capsules, or by some other means?

When cattle are affected clinically with grass tetany they display initial excitement, bellowing, muscle spasms, tetany and finally convulsions before dying.

Since grass tetany leads to the rapid death of cattle, the treatment of clinical cases is an emergency and veterinary assistance should be sought immediately. A veterinarian will give a calcium and magnesium solution intravenously.

If a veterinarian is not available, the calcium and magnesium solution should at least be given under the skin.

Clinical cases of grass tetany and cattle lost to the condition are best prevented with some forward planning.

For further advice, contact your local veterinarian or Agriculture Victoria veterinary officer or animal health officer.