Manufacturer: Bomac Animal Health Pty Ltd Registered Name Magnesate Magnesium Sulfate Injection for Cattle Composition Magnesium sulfate 500 mg/mL. Actions Pharmacology The ruminant hypomagnesaemic tetanies are a group of diseases occurring in both sexes and across a range of species and ages, and under a variety of dietary, nutritional and management conditions. The pathophysiology is not fully understood. Grass tetany, lactation tetany, hypomagnesaemia, hypomagnesaemic tetany and grass staggers are all part of the classic metabolic condition associated with tetanic convulsions and observed most commonly in lactating cows grazing on lush rapidly growing pasture. Although most common in lactating cows, the syndrome is also seen in calves, yearlings, bulls, steers and nonlactating cows, as well as in sheep. A high physiologic demand for magnesium accompanied by a reduction in the amount of magnesium absorbed from the digestive tract are the main factors predisposing ruminants to hypomagnesaemic tetanies. Magnesium is lost from the body in faeces, urine and milk. An individual cow may lose up to 3 g/day in the milk, and this is often the factor that changes the magnesium balance from positive to negative. The acute disease can also be precipitated by stress, usually in the form of sudden adverse weather conditions or transient food deprivation. The critical factor for the initiation of tetany is the level of magnesium in the cerebrospinal fluid (CSF), which normally remains within strict limits despite wide variations in serum levels. Once magnesium levels in the CSF fall below 0.6 mmol/L, tetany may be expected. A fall in serum magnesium ion concentration is also characteristic in affected animals; cattle with serum magnesium levels below 0.042 mmol/L are at risk of tetany. Subcutaneous administration of Magnesate provides a sustained response in the elevation of serum magnesium levels in animals affected by hypomagnesaemia. The sooner treatment is commenced after the onset of tetany, the more effective the therapy is likely to be. Indications Hypomagnesaemia (grass tetany, lactation tetany, grass staggers) in cattle. Precautions Caution: avoid carcass damage. Sterilise all injection apparatus by boiling before use. Avoid use of strong disinfectants on apparatus. Maintain cleanliness at all times. Keep needles sharp and clean. Replace frequently. Use shortest needle possible, certainly not exceeding 15 mm. This product must be injected only under the skin. Disposal Dispose of empty container by wrapping with paper and putting in garbage. Withholding Periods Nil. Dosage and Administration 60 to 120 mL by subcutaneous injection. In cases where the animal is at risk of severe injury from continuous tetanic convulsions, symptomatic treatment with sedatives or tranquillisers is recommended. To prevent recurrence, the magnesium status of the animal may be improved by appropriate management of soil and pasture, use of intraruminal magnesium ‘bullets’, and by direct supplementation of the diet using magnesium treated hay, magnesium containing licks, and the addition of magnesium salts to water supplies.
