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Beef producers advised to be aware of deadly disease

For beef producers, losing adult cows to ‘grass tetany’ can be a devastating experience.  In many cases, it’s mature, well-conditioned cows with calves that are affected – often without warning.

Grass tetany is most often seen over winter, and Central Tablelands Local Land Services District Vets have started to see cases this year.  Beef producers are being advised to keep a lookout for animals with early symptoms, and to consider preventative strategies in their herd.

Dr Amy Masters, Central Tablelands Local Land Services District Vet in Orange, says recent cases have been typical of the disease.

“Older lactating cows are at the greatest risk, and the cases I’ve seen in the district recently have followed this pattern”, Dr Masters said.

“Grass tetany is a metabolic disease in which magnesium levels decline in blood and spinal fluid.  The result is that affected animals often show neurological symptoms like a stiff gait, agitation, apparent blindness, staggering, bellowing, or seizures.  In some cases animals can die suddenly without warning”.

Many factors can combine to cause outbreaks of grass tetany, making the disease hard to predict.  Pastures which are low in magnesium or high in potassium (such as grazing cereal crops or young, grass-dominant pastures) pose a higher risk, while legumes generally contain higher magnesium levels.

“Cattle require a constant intake of magnesium”, says Dr Masters, “so lactating cows are often the ones affected, since they are losing magnesium in milk.  Other stress factors, like yarding or transport, can also cause grass tetany”.

“One option is to provide a magnesium supplement to at-risk animals during late autumn and winter.  This can be done by providing a loose lick, spreading magnesium on hay, or mixing magnesium with grain or other supplementary feeds”.

Beef producers are advised to contact their Local Land Services District Vet or private veterinarian for more information on preventative strategies.  If animals affected by grass tetany are identified early, rapid treatment can be life-saving.

“An injection of magnesium can be used to rapidly restore correct magnesium levels”, explains Dr Masters.  “Where animals are showing neurological symptoms it’s always best to contact a vet to ensure the correct treatment is provided.  In cases of sudden death, District Vets can also perform a post-mortem to determine the cause of death”.

Media enquiries: Kylie Krause | 0439608370