Time for Tetany??
Early spring is the period when cattle are at most risk for grass tetany in Iowa. Grass tetany is actually a magnesium deficiency (hypomagnesemia). The problem occurs at different times of the year worldwide, but the timing seems to have a few things in common. Lush spring grass can grow very fast if the growing conditions and fertility are right. Usually this involves plenty of moisture and fertility. Grass that is susceptible to producing grass tetany often is low in magnesium (Mg), calcium (Ca) and sodium (Na), but higher in potassium (K). Grass tetany can occur in legume-grass mixtures when the temperature is below about 60 degrees since much of the growth at that stage will be grass. Grass that is conducive to producing tetany in cattle usually is high in protein, but high enough in water to limit the intake of energy by the cattle.
To learn more about which animals are most susceptible to grass tetany and how to prevent it, see the April 2011 Growing Beef newsletter.