Spring is here and when cows begin grazing the lush spring growth, grass tetany, also called grass staggers, wheat pasture poisoning and hypomagnesia can start showing up. Grass tetany is a nutritional disorder resulting from inadequate blood levels of magnesium. Conditions which increase the risk of grass tetany are lush green forage, prolonged cloudy weather, older cows in early lactation that are heavy milkers and soils that are low in magnesium and calcium and high in nitrogen and available potassium. The older cows in early lactation are more prone to grass tetany, since cattle become less efficient at mobilizing body stores of magnesium as they mature.
Further complicating the situation, cattle have a limited ability to store magnesium in the body, since magnesium is rapidly excreted through milk, urine and feces. Clinical signs usually begin with incoordination, salivation, nervousness, staggering, convulsions and death
Prevention is the best treatment; providing supplemental magnesium after the development of a problem will usually not correct the problem. To prevent grass tetany, dry cows should consume 10 grams of magnesium per day, while cows nursing calves should consume 20-25 grams of magnesium daily.
To provide this level in the body, a commercial mineral mix containing at least 10 percent magnesium is recommended. High Magnesium mineral programs should be included in your cowherd management program beginning in late March or early April as the lush spring forage growth starts. So acceptable levels will be achieved in the body to prevent problems later in spring.
For producers who want to mix their own High Magnesium Mineral: a mixture of 30% magnesium oxide, 30% trace mineralized salt, 30% dicalcium phosphate and 10% dried molasses fed free choice will achieve the recommended levels of magnesium. Incorporating legumes into pastures or feeding hay that contains red clover or alfalfa will also help minimize grass tetany problems, sinces legumes contain about twice as much magnesium as grasses.
If you are interested in learning more contact the University of Missouri Extension Center in your area or myself Jim Humphrey, Andrew County Extension Center, (816)324-3147 firstname.lastname@example.org