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Hypomagnesaemia (Grass Staggers) in Cattle: Welfare Emergency

Grass staggers is a rapidly fatal metabolic emergency in cattle. This guide covers welfare-centred recognition and emergency management.

Key Facts

Hypomagnesaemia occurs when blood magnesium falls below critical levels
Grass tetany most commonly affects spring-calving cows on lush pasture
Signs develop rapidly: muscle tremors, staggering, hypersensitivity, and convulsions
Death can occur within hours without treatment
Magnesium cannot be stored in the body so daily supply is essential
Prevention through magnesium supplementation is the most effective welfare measure

Welfare Considerations and Management

Grass staggers is a welfare emergency requiring immediate treatment. Intravenous or subcutaneous magnesium sulphate solution provides rapid correction. The animal must be handled very calmly as excitement can precipitate fatal cardiac arrhythmias. Prevention through daily magnesium supplementation (calcined magnesite in feed, magnesium bullets, or magnesium-rich mineral licks) is essential during high-risk periods — typically spring turnout and autumn flush.

What You Can Do

Supplement cattle with magnesium daily during spring turnout and autumn flush
Approach and handle suspected hypomagnesaemia cases extremely calmly
Have injectable magnesium sulphate readily available during high-risk periods
Contact your vet immediately — this is a welfare emergency with a good prognosis if treated promptly