Grass tetany is a highly fatal disease in cattle associated with low levels of magnesium in the blood. Rapidly growing cool season grasses will often not have enough available magnesium to support a cow’s needs. Grass tetany is more prevalent in cool springs or after a cool stretch of weather in a wet spring. Pastures that have been fertilized also seem to be more prone to grass tetany. Cows are most vulnerable to grass tetany once they calve and begin to lactate. Their requirement for magnesium will almost double at this time. It is actually quite common to hear that the best milking cows are the ones that go down with grass tetany. This is because their magnesium requirement is higher than a cow with lower milk production.
Cattle cannot store any appreciable amount of magnesium in their body, so we must provide supplemental amounts daily. While magnesium oxide is generally considered a good source of supplemental magnesium, it has one important drawback in that it is very unpalatable.
So, what is a cattleman to do when you need to provide a daily dose of something that tastes bad? Fortunately, Hinton Mills provides a variety of products to help. These products are available in different forms such as loose mineral products, protein tubs, and pressed blocks. Our supplements are available 24/7 and the molasses easily masks unpalatable ingredients. You should begin providing High-Mag supplements approximately one or two weeks before you suspect any bouts of grass tetany. This is not to build up magnesium stores, but to make sure cattle are consistently consuming the product when grass tetany season arrives in your pastures. We recommend you start feeding high-mag products now.