Agriculture Victoria is reminding farmers to be vigilant, with grass tetany a significant problem in cattle at this time of year.
District veterinary officer Jeff Cave said the first sign of grass tetany could be a deceased cow, as cattle often died suddenly.
Grass tetany occurs when blood magnesium levels are low, hence the condition’s other name — hypomagnesaemia.
To prevent grass tetany, Dr Cave said magnesium supplementation needed to be given daily to cattle at greatest risk during periods of greatest risk.
To establish the likelihood of grass tetany occurring on your property, he said it was worth considering some of the risk factors involved, which could include grazing on immature, rapidly growing, grass-dominant pastures, soils high in potassium, or with the heavy use of nitrogen or potash fertilisers.
According to Agriculture Victoria, older, fatter cows that have recently calved are most likely to be affected, with low blood magnesium levels in cows and cool and cloudy weather also factors to be considered.
Dr Cave said cattle affected clinically with grass tetany could display initial excitement, bellowing, muscle spasms, tetany and finally convulsions before dying.
Since grass tetany led to the rapid death of cattle, he said treatment of clinical cases was an emergency and veterinary assistance should be sought immediately.
Dr Cave said a veterinarian would give a calcium and magnesium solution intravenously, but if a veterinarian was not available, the calcium and magnesium solution should be given under the skin.
■For further advice, contact your local veterinarian or Agriculture Victoria veterinary officer or animal health officer, or in NSW your Local Land Services.