Grass Tetany/Transit Tetany

Hilltops Phoenix

A few cases of grass/transit tetany reported in both cattle and sheep lately, it is time to consider our options.

There have been reported cases of hypomagnesmia in lambs.

Also be careful of bringing stock from areas that are less fortunate than ours at the moment, give them time to properly adjust, provide them with good quality roughage so they do not gorge feed on arrival to their new home.

Remember prevention is always far better than cure.

Grass tetany is most common in lactating beef or dairy cows, but can affect all classes of stock. Grass Tetany is also known as hypomagnesaemia.


Low magnesium levels in the blood and fluid surrounding the brain.

– High potassium and nitrogen interfere with magnesium absorption in the rumen.

– Cattle depend on frequent intake of magnesium to maintain normal blood levels.

Risky Situations

Problem pastures include:

– Short green pick after the break which is low in magnesium, high in potassium and protein.

– Grass dominant pastures. They are low in calcium and sodium.

– Sudden cold, wet, windy weather, particularly when there is little shelter.

– Cold soils. Usually have more nitrogen which affects the ability of animal to absorb magnesium.

– High use of potassium and/or nitrogen fertiliser.

At risk stock include:

– Sudden starvation of fatter, older cows.

– Cows in early lactation. They have a high requirement for magnesium and are therefore at greater risk.

– Older cattle.

– Stock in transit that have been held over off feed.

– Stock brought in from areas with lesser feed quantity and quality that are under stress.


– Usually, the first sign is a dead cow in the paddock with froth from the mouth and nose.

– Initial signs are face and ear twitching, wary appearance and stiff gait.

– Intermediate signs are “goosestepping” (tail and head held high), galloping and loud bellowing.

– Advanced signs are convulsions, profuse salivation, staggering.

– Cattle will typically lie down on their side with legs outstretched, stiff and paddling.


If caught early:

– A 4-in-1 injection (FLOPAK Plus) can be given under the skin.

– Treatment is often unsuccessful, but grass tetany is easily prevented with early magnesium supplementation and good management.

Prevention & Management:

Pasture management

– If possible remove stock from problem paddocks until the pasture is more mature.

– Speak to a Landmark agronomist regarding fertiliser practices in problem paddocks.

Feed management

– Provide good quality legume hay to provide a source of calcium & magnesium.

Minimise stress

– During risky periods e.g. yarding, transportation.

Supplement magnesium

– Sodium is necessary for magnesium absorption, therefore salt should be included when supplementing magnesium.


A free choice lick with high levels of magnesium.

4 Season Co. MMM block

– Contains Magesium, Minerals and Molasses for palatability and better intake.

Lienert Australia Loose Licks

– Two weatherproof options are available.

Supplamins Hi-Mag for cattle only and Supplamins

Mid-Mag for sheep and cattle (does not contain copper).

Magnesium Oxide (e.g. Causmag)

– 60g/head/day mixed into a slurry with water and poured over hay daily.

Contact the friendly team at Landmark Young
99 Lovell St Young 02 6382 7600

Landmark Young
Landmark Young

Ph: 02 6382 7600

99 Lovell St, Young

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