– Ted Wiseman, OSU Extension, Perry County
We’re currently 60 growing degree days above last year and many plants have broken dormancy. Are you ready?
Although we haven’t had much of a winter so far, and I hope I’m not jinxing us by mentioning it here. We have had above average temperatures for January with February 5 to 10 degrees above the long-term average for the state. To date we are currently 60 growing degree days above last year. Regardless of what weather conditions encountered until spring officially arrives, many plants are already breaking dormancy. This includes pastures, so adjusting our mineral program now will be cheap insurance to prevent grass tetany.
Preparing for the early grazing season it is important that your mineral program complement the feeds you are feeding now. One of the major problems livestock producers encounter in the early spring is grass tetany, also known as grass staggers, spring tetany or lactation tetany. So what causes grass tetany? Grass tetany typically occurs in the spring, but can occur in the fall or when you have rapidly growing, succulent, cool season grasses. This condition is a metabolic or nutritional condition in dairy, beef cattle and sheep with low blood levels of magnesium. Lush green grasses are generally low in magnesium, but is made worse by having high potassium and protein levels. Mineral imbalances of high potassium and nitrogen along with low calcium, sodium and phosphorus levels can tie up magnesium in the soil making the problem worse. This is another reason for soil sampling and why you should apply fertilizer based on results, use no more potassium than needed since grasses are luxury consumers of potassium.
Feeding high magnesium mineral supplements is a preventative measure to reduce or prevent grass tetany. Cows require 20 grams of magnesium daily which can be accomplished through consuming 3 to 4 ounces per day of a mineral mix containing 12 to 15 percent magnesium. Just because you provide high magnesium mineral mix doesn’t mean your livestock are in the clear. You need to monitor mineral intake and make sure all animals are consuming desired amounts. Magnesium alone can result in decreased palatability, and decrease consumption. If livestock do not consume adequate levels from a free choice mineral mix, the supplemental magnesium can be combined with more palatable feeds such as dried molasses or soybean meal. In addition, adding salt may help increase mineral intake but also ensure sodium requirement is being met. This is NOT replacing magnesium it is critical you are monitoring magnesium intake. Commercial mixes are available, and a few University Specialists have provided home-made mineral mixes online. The high magnesium mineral supplements should be provided prior to turning livestock out onto lush pastures. Recommendations that I have found suggest provided these supplements 2 weeks to 30 days prior to turning out livestock onto pastures. High magnesium supplements do not need to be provided year round, but will not create any problems you feed it too early or late into the season.
Females are more prone to the disease especially the older heavy lactating females. Steers, heifers, dry cows and growing calves are less susceptible, but can still contract tetany in the right conditions. Symptoms often include going off feed, nervousness, show muscle spasms, convulsions, irritability, lapse into a comma, aggressiveness and lastly death. Producers should keep a close eye on livestock in the early grazing season, since these symptoms often occur rapidly. Should you suspect grass tetany contact your veterinarian immediately.