Hypomagnesaemia, also known as grass tetany, is often an issue that is not thought about or considered until it is too late.
When left undetected, cases could prove to be very costly to farmers, with it likely resulting in the loss of an animal.
Agriland has heard of a number of cases whereby farmers have been caught out by tetany already this year, so it is something to be cautious of.
Grass tetany
Freshly calved cows are currently in the transition period, which is a high-risk period for cows to suffer from metabolic disorders.
Like other metabolic disorders, tetany can have a significant impact on cow performance during the subsequent lactation.
Good grass growth over the winter, followed by dry conditions, means that many herds are now grazing cows.
Risk factors for grass tetany include lush grass rich in potassium (K) and nitrogen (N) in cold and wet conditions.
The colder weather conditions currently being experienced by almost all of the country could make it a high-risk period for tetany.
It also occurs when cows are let out to lush low-fibre pastures, making it something to be cautious of over the coming months.
What to look for?
The symptoms of grass tetany can occur rapidly and mainly 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.
Cows that are showing possible symptoms need to be looked at and/or treated promptly by a vet.
Prevention
Like most things, prevention is better than cure, and the best way to prevent cases of tetany is to supplement the animals diet with magnesium (Mg).
Cows need to be supplemented with 30g of Mg (or 60g of calcined magnesite)/day during the high-risk period.
The need for this should be discussed with your vet and/or nutritionist to determine if your herd requires supplementation.