Prevent, watch for grass tetany

Apr 12, 2013
by WLJ

As pastures start to green up in the eastern Corn Belt, cattle producers need to be aware of the risk of grass tetany in grazing animals, a Purdue Extension beef specialist says.

Grass tetany, or grass staggers, is a nutritional disease that cattle get from grasses high in water content and potassium and low in other nutrients, such as magnesium and calcium. Older cows that have just calved and are in peak lactation are the most susceptible.

The risk increases in pastures that have been heavily fertilized with nitrogen, so those producers who have spread fertilizers such as poultry litter, hog manure or urea are more at risk.

While the condition is treatable if caught early enough, Ron Lemenager said it’s best to prevent it altogether.

“The easiest way to prevent grass tetany is to start these cows on a high magnesium mineral prior to going to grass in the spring,” he said. “That mineral mix should have a minimum of 8 percent magnesium, and it could be 12 percent or higher.”

The problem with a high magnesium supplement is that the source is typically magnesium oxide, which isn’t something cattle like to eat.

“What we’ll see is that a lot of commercial mineral mixes containing magnesium will include a palatability enhancer—something like dried distillers grains, soybean hulls, wheat midds or dried molasses—to help encourage consumption,” Lemenager said.

“We’re looking at, typically, 4 ounces of mineral consumption to get adequate levels of magnesium when it’s included in the supplement at 8 to 12 percent.”

The peak season for grass tetany is April through early May, so now is the time to keep an eye on grazing animals. If a cow is stricken with grass tetany, the cattle producer doesn’t have long to respond. Often, cows will die within 2-3 hours of the first symptoms.

Those symptoms include stumbling and staggering, trembling muscles, muscle twitches, excitability, stiff gait, grinding teeth and eventually violent convulsions, coma and death.

More information on grass tetany can be found at The — WLJ