Grass tetany in cattle – predicting its likelihood

NSW DPI - Mac Elliott

Type: PDF
Knowledge level: Intermediate

Farm Table says:

Interesting article on predicting the likelihood of grass tetany in your enterprise. I was surprised to learn there are 3 types of grass tetany, all of which cause the same deficiency and symptoms.

This fact sheet discusses the likelihood of grass tetany occurring in cattle. Grass tetany can often be deadly in cattle so it is important for producers to be aware of the causes and symptoms so they can take preventative measures in their enterprise to stop grass tetany occurring.

The items covered in this article were:

• What is the cause of grass tetany?

• Types of grass tetany

• Predicting grass tetany

Key points were as follows:

• Three types of grass tetany exist (grass/crop tetany, post drought grass tetany and penned feeding grass tetany)

• A mild cause of grass tetany is a deficiency in magnesium.

• A more severe case of grass tetany is where cattle have high amounts of potassium in their stomach which slows down magnesium absorption. High potassium levels can be caused from a range of factors (cattle graze pastures on soils naturally high in potassium, cattle graze pastures fertilised with inappropriately high levels of potassium fertiliser, cows are deficient in salt (sodium) or the diet is changed from hay or dry feed to lush pasture).

• Depending on the severity of the case, symptoms can range from froth around the mouth/nose, muscle spasms, twitching, stiff movement, staggering, overly excited, galloping or acting in a wild behaviour.

• Pasture management plays an important role in eliminating magnesium rich pasture as spraying broadleaf weeds results in no clover and grass being the main source of nutrition. Higher grass dominance means higher risks of grass tetany.

• Cows that have a calf at foot or cows that are lactating are more likely to be affected by grass tetany as they can only store small amounts of magnesium in their bodies at a time.

• The main preventative measure that can reduce the occurrence of grass tetany is a product called causmag (magnesium oxide) which can be fed to cattle on supplements such as hay. Other preventative measures are lick blocks, homemade remedies, magnesium bullets or through medicating water in available water troughs.

2008 - Australia - NSW DPI - Mac Elliott
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