Cattle producers in South West Victoria are being urged to stay alert to the threat of grass tetany.

The Victorian Department of Primary Industries (DPI) has advised of increased risk levels in coming months.

Grass tetany, also known as hypomagnesaemia, occurs when blood magnesium levels are low.

In a warning issued today DPI District Veterinary Officer Steve Pefanis said at this time of year, grass tetany could potentially cause a major problem in cattle.

“Since cattle with grass tetany often die suddenly, the first sign of grass tetany on your property may be a dead cow. Naturally, this is a situation you would prefer to prevent,” Dr Pefanis said.

To establish the likelihood of grass tetany occurring on your property it is worth considering some of the following risk factors:

• Grass tetany is associated with immature, rapidly growing, grass dominant pastures.

• It is associated with soils that are 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.

• Grass tetany is most likely to occur during cool and cloudy weather.

Dr Pefanis said after famers had considered these risk factors it was worth planning how they could prevent, and if necessary treat, an outbreak of grass tetany on their property.

“As cattle’s bodies are unable to store magnesium, to prevent grass tetany, magnesium supplementation needs to be given daily to cattle during periods of greatest risk,” he said.

“Supplementing your herd can be done by giving treated hay, mineral licks, magnesium capsules, a combination of these or other available treatments.”

Dr Pefanis said 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 situation and veterinary assistance should be sought immediately. A veterinarian will give a calcium and magnesium solution intravenously,” he said.

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

Farmers seeking further information or advice are urged to contact Steve Pefanis or Tyrone Cain at DPI Colac on (03) 5233 5504.