Preventing, treating grass tetany | TSLN.com

Preventing, treating grass tetany

Dave Barz, DVM

For the May 8, 2010 edition of Tri-State Livestock News.

Spring is definitely here. The pastures are growing, but the wet cold weather has really slowed their maturity. When the weather warms after these wet rainy days the grass will grow rapidly. This fast growth and turnout of your lactating mama cows could result in grass tetany.

Deficiencies in the bodies magnesium (Mg) levels cause grass tetany symptoms. About 70 percent of the animal’s Mg is stored in the bones. This is not readily available if the animal’s blood levels drop. This means that daily requirements must be supplied by the diet. When plants are small and growing rapidly they tend to be low in Mg and high in potassium and protein/nitrogen. The potassium and protein interfere with the absorption and utilization of Mg and calcium (Ca) from the grasses.

Cows in their first 60 days of lactation are most susceptible, but calves and yearlings may also be affected. Older cows are not as efficient at mineral absorption and may be more susceptible than younger animals. If you treat an animal, she should be culled from the herd because she will probably relapse if stressed again.

Many times you will merely find the affected animal recumbent and unable to get up. If it does get up, watch out, it will probably chase you. They become easily excited and are very aggressive. Early signs include nervousness and failure to eat. This rapidly progresses to muscle twitches and irregular gaits and staggers. The animal then collapses when excited. Once the animal is down they become comatose and later die of respiratory failure.

Treatment with intravenous Ca and Mg will reverse the symptoms in several minutes. This should be administered slowly to avoid shock. Epsom Salt solutions (Magnesium sulfate) may be administered under the skin. The animals usually totally recover in several hours.

Mg may also be added as a herd treatment. If you feed alfalfa hay, it will have high levels of Ca and Mg. This will improve the levels in the cows after several days.

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Prevention is usually accomplished by feeding 1-2 oz of magnesium oxide. This is very unpalatable to the cow and must be mixed with grain or a flavoring agent. Free choice mineral mix should contain about six percent Mg and the cow should be eating 2-3 oz per day before turnout.

It is best not to turn cattle out until the grass is 4-6 inches tall. If you have pastures which are high risk, turn out dry cows, yearling, or cows late in lactation, as this will lower the risk.

Grass tetany is common problem in our area. Treatment is successful if the animals are identified early. It is best to prevent the problem by:

• Allowing grasses to mature;

• Pre feeding alfalfa and high Ca mineral;

• Force feeding Magnesium before turnout;

• Selecting animals which are less susceptible.

Consult with your veterinarian or nutritionalist and devise a preventative program which will benefit your herd. Careful planning and management will minimize your losses and improve your pasture utilization.

Spring is definitely here. The pastures are growing, but the wet cold weather has really slowed their maturity. When the weather warms after these wet rainy days the grass will grow rapidly. This fast growth and turnout of your lactating mama cows could result in grass tetany.

Deficiencies in the bodies magnesium (Mg) levels cause grass tetany symptoms. About 70 percent of the animal’s Mg is stored in the bones. This is not readily available if the animal’s blood levels drop. This means that daily requirements must be supplied by the diet. When plants are small and growing rapidly they tend to be low in Mg and high in potassium and protein/nitrogen. The potassium and protein interfere with the absorption and utilization of Mg and calcium (Ca) from the grasses.

Cows in their first 60 days of lactation are most susceptible, but calves and yearlings may also be affected. Older cows are not as efficient at mineral absorption and may be more susceptible than younger animals. If you treat an animal, she should be culled from the herd because she will probably relapse if stressed again.

Many times you will merely find the affected animal recumbent and unable to get up. If it does get up, watch out, it will probably chase you. They become easily excited and are very aggressive. Early signs include nervousness and failure to eat. This rapidly progresses to muscle twitches and irregular gaits and staggers. The animal then collapses when excited. Once the animal is down they become comatose and later die of respiratory failure.

Treatment with intravenous Ca and Mg will reverse the symptoms in several minutes. This should be administered slowly to avoid shock. Epsom Salt solutions (Magnesium sulfate) may be administered under the skin. The animals usually totally recover in several hours.

Mg may also be added as a herd treatment. If you feed alfalfa hay, it will have high levels of Ca and Mg. This will improve the levels in the cows after several days.

Prevention is usually accomplished by feeding 1-2 oz of magnesium oxide. This is very unpalatable to the cow and must be mixed with grain or a flavoring agent. Free choice mineral mix should contain about six percent Mg and the cow should be eating 2-3 oz per day before turnout.

It is best not to turn cattle out until the grass is 4-6 inches tall. If you have pastures which are high risk, turn out dry cows, yearling, or cows late in lactation, as this will lower the risk.

Grass tetany is common problem in our area. Treatment is successful if the animals are identified early. It is best to prevent the problem by:

• Allowing grasses to mature;

• Pre feeding alfalfa and high Ca mineral;

• Force feeding Magnesium before turnout;

• Selecting animals which are less susceptible.

Consult with your veterinarian or nutritionalist and devise a preventative program which will benefit your herd. Careful planning and management will minimize your losses and improve your pasture utilization.

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