Grass tetany can be a cattle killer

May 04, 2009

University Park, Pa. — The calendar says it is the beginning of spring and the grass is growing. For most beef producers, it is a welcome time of the year because there are no more cold, snowy days when they have to feed their cattle hay.

However, there is a hidden danger in those pastures from grass tetany, according to John Comerford, associate professor of dairy and animal science, who coordinates of beef programs in Penn State's College of Agricultural Sciences.
"This syndrome is a result of low magnesium levels in cows' circulatory and nervous systems, and it is most common when lactating cows graze lush, green pastures," he said. "It occurs more frequently when pastures have been fertilized with potassium and nitrogen and when solids are naturally high in potassium and low in sodium."
The disease results from low magnesium and sodium intake, high potassium intake, and low blood calcium levels due to heavy lactation, Comerford explained.
"Grass tetany can cause erratic behavior in cows," he said. "Restlessness, stumbling, nervousness, isolation and sometimes a high-stepping movement are symptoms. Without treatment, the disease can quickly kill cattle with these advanced symptoms."
Treatment for grass tetany usually requires a veterinarian to administer intravenous injections of magnesium-based compounds. When a veterinarian is not available immediately and the cow has advanced symptoms of the disease, Comerford noted that a precautionary treatment can be applied by saturating a pint of water with Epsom salts and injecting up to 10cc of this solution in multiple locations of muscle at least 4 inches apart.
"Grass tetany usually is prevented by making an appropriate mineral mixture available to grazing cattle," he said. "Commercial mineral mixes that are high in magnesium are readily available."
 A mix that includes a selenium supplement can be made at home, which also features a selenium supplement, with the following recipe: 22.5 percent trace-mineralized salt, 22.5 percent dicalcium phosphate, 10 percent 0.06% selenium mix; 22.5 percent magnesium oxide and 22.5 percent ground corn. Cattle should eat about one-fourth pound of the mixture daily.
  • IMAGE: Greg Grieco

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Last Updated November 18, 2010