In the early stages, animals may show incoordination, extreme excitability and quivering at the slightest noise. Death may occur within three days after the first symptoms. Many times, animals on pasture are found dead without illness having been observed.

Generally, the grasses which cause tetany are those low in magnesium and soluble carbohydrates and high in potassium and crude protein.

Grass tetany is likely to occur when the magnesium contest of an animal's diet dry matter is less than 0.2 percent. There should be no problem if a forage's magnesium level is 0.2 percent or higher unless there is a high level of potassium and/or protein.

Prevention measures should be primarily aimed at boosting the magnesium and energy intake of susceptible animals during danger periods.

This can be done by supplying 0.5 ounce (for mild risk cattle) and two ounces (high risk) of magnesium oxide per head each day in a commercial or homemade product. There are some very good commercial mineral mixes that contain adequate magnesium.

When the risk of tetany is slight to medium and a homemade product is preferred, a mineral mix containing equal parts cottonseed meal, trace mineral salt, magnesium oxide and dicalcium phosphate can be fed on a free-choice basis.

If the risk of tetany is high, mix six pounds of magnesium oxide, ten pounds of dicalcium phosphate, 16 pounds of cottonseed meal, three pounds of trace mineral salt, and 65 pounds of grain. Hand feed the mixture at a rate of two pounds per head per day.

As an alternative to the latter mixture, you can mix seven pounds magnesium oxide, 10 pounds dicalcium phosphate, 20 pounds cottonseed meal, 20 pounds salt, three pounds trace mineral salt and 40 pounds grain. Feed free-choice.

Source: The Baxter Bulletin