Cattle that experience nutritional stress while grazing the first lush growth of high-quality small grains and ryegrass pastures may become vulnerable to grass tetany. These fast-growing forages may be high in nitrogen and low in magnesium resulting in grass tetany susceptibility. As these forages mature, the likelihood of a problem is reduced.
Grass tetany is a nutritional imbalance in cattle resulting from reduced magnesium levels in the blood. It is sometimes referred to as grass staggers, winter tetany, or hypomagnesemic tetany.
Signs of grass tetany include nervousness, lack of coordination, muscular spasms, staggering and death. If grass tetany is suspected, a veterinarian should be contacted immediately to diagnosis and treat animals. Death may occur soon after the first signs of grass tetany are observed.
The key to avoiding grass tetany is prevention. Supplying cattle with a complete mineral mix that is high (10 – 15%) in magnesium can prevent cattle from being deficient in magnesium. Although a serious problem, it can be avoided by providing proper mineral nutrition at the appropriate time of the year. Livestock managers are encouraged to begin supplementing high mag mineral prior to grazing forages that could result in grass tetany issues.
For more information on Grass Tetany, follow this University of Florida/IFAS link: https://edis.ifas.ufl.edu/pdffiles/DS/DS13700.pdf