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Grass Tetany: Prevention is better than Cure

26 September 2019
Type Media Article

By Ciaran Beatty, Teagasc Drystock Advisor, Castlerea

The one sight that no Suckler farmer wants to see is the dead body of one of his best Suckler Cows out in the field. Too often, this is the only sign of Grass Tetany at this time of the year on some farms. Grass Tetany is an acute Magnesium Deficiency in the blood in lactating cows which is potentially fatal. Magnesium is vital for the proper functioning of nerves and muscles and once it comes under pressure it will begin to affect the movement and temperament of the animal. Animals will become excitable, nervous and unsteady on their feet often staggering and falling over with heart failure and death quickly resulting.

The main causes of Grass Tetany are poor feed intake, cold and wet weather, Stress especially at weaning time and high Potash applications in springtime can also result in diminished levels of magnesium. Where farmers are lucky enough to identify the disease, a Vet should be called immediately and treatment involving the administration of Magnesium Sulphate carried out as soon as possible. Prevention is better than cure and way cheaper and Tetany can be prevented by;

  • Provision of a Magnesium treated ration/nut daily as animals cannot store magnesium in the body and a constant supply is required during critical periods.
  • The provision of Magnesium blocks/licks out in the field.
  • The provision of Magnesium Compounds in the drinking water supply.
  • The provision of hay or well wilted silage to slow down the digestion process of the animal and allow for better absorption of Magnesium from the diet. Some farmers may provide a combination of such measures to reduce the risk especially during the September/October period when risk is at its greatest.

Remember that the value of even one cow lost from Tetany would cover the cost of years of prevention/protection for that herd!

Teagasc provides a Local Advisory and Education service to farmers. They have offices based in Longford Town (Tel: 043 3341021), Roscommon Town  (Tel: 090 6626166) and Castlerea (Tel: 094 9620160). You can find us on Facebook @Teagascroscommonlongford.