Extension Communications
Extension 4-H Youth Building
Ames, Iowa 50011-3630
(515) 294-9915
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Extension Communications |
4-14-04
Contacts:
Stephen Barnhart, Agronomy, (515) 294-7835, sbarnha@iastate.edu
Rachel E. Martin, Iowa Beef Center, (515) 294-9124, remartin@iastate.edu
Manage Grass Tetany in Beef Herds
AMES, Iowa - Grass tetany, while not highly prevalent in Iowa, can cause serious problems to a herd with little or no warning. Also known as hypomagnesemia, grass tetany occurs most often in spring and fall, when forages are rapidly growing, resulting in low magnesium (Mg) amounts, and therefore a deficiency of Mg in cattle.
Perhaps the biggest challenge of grass tetany is to identify it before it becomes a lethal problem. Many symptoms, including excitability, lack of coordination, grinding teeth and trembling muscles, can indicate several different illnesses, making diagnosis difficult when time is of the essence.
"Because of the difficulty in detecting grass tetany in cattle before it has a substantial impact on animal health, it's important for producers to prevent low magnesium levels in forages before the herd is affected," says Stephen Barnhart, forage specialist, Iowa State University Extension. "The challenge becomes changing the composition of the pasture's forage."
Manipulating plant magnesium content is a complex issue, says Barnhart. He recommends using forages that have higher magnesium content, such as more legumes. Second, fertilization management is crucial. A magnesium-containing ag lime or magnesium-containing liquid fertilizers may provide a partial boost to Mg levels. High levels of nitrogen (N) and potassium (K) reduce plant magnesium content, so producers are cautioned to not over fertilize with K and to split applications of nitrogen and nitrogen-rich nutrient sources such as poultry litter.
"The take-home message is to not over-fertilize your pastures if you suspect or anticipate grass tetany," says Barnhart. Of course, Mg is often supplemented to cattle directly via mineral mixtures, concentrates and legume hay.
For more information on grass tetany pasture management, visit www.iowabeefcenter.org or contact Stephen Barnhart at (515) 294-7835.
The Iowa Beef Center began operation in 1996 to support the growth and vitality of the beef cattle industry of the state. A part of Iowa State University Extension, the Iowa Beef Center is the central access point for Iowa State University programs related to the beef industry. For more information, visit the Web site at www.iowabeefcenter.org or call (515) 294-BEEF.
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