After the much wanted rain has come and grass growth is beginning to return to somewhat normal levels – it’s important to be weary of grass tetany.
Grass tetany can happen at any time of the year, with periods of high growth increasing the risk of tetany occurring.
Tetany often occurs when cows are let out to lush, low-fibre pastures; so it is something to be conscious of over the coming weeks, as growth rates begin to recover.
Severe cases can have an impact on the future production of cows – any disease/disorder that impacts a cows performance should not be over looked.
Symptoms
The symptoms of grass tetany generally occur rapidly and usually impact the animal’s nervous system.
Symptoms include:
- Severe muscle contractions;
- Hyperness;
- Frothing at the mouth;
- Staggering while walking or standing;
- Body tremors;
- Visual distress;
- Irregular and loud heartbeat.
Treatment is administered through an intravenous injection of a combined magnesium (Mg) and calcium (Ca) solution.
If you are concerned about a cow having grass tetany, acting quickly is important. A cow showing symptoms should be accessed and treated promptly to avoid further deterioration and possible death.
Grass tetany prevention
The best way of preventing grass tetany is to supplement the animal’s diet with Mg.
A source of Mg should be included in a cow’s diet at all times of the year. Cows should receive 30g of Mg cow/day to prevent grass tetany.
Methods of providing Mg
There are several methods of providing Mg to cows while grazing, including the following.
Dusting pasture with Cal-Mag at a rate of 15-17kg/ha – once/week. This should be done twice daily during wet weather.
Probably the most commonly used method on Irish farms is feeding a high Mg concentrate. The amount of Mg should be adjusted depending on much concentrates are being fed.
Some other methods include adding soluble Mg solution to water troughs, administering a bolus and providing a high Mg lick to cows.