What is grass tetany and when does is occur?
Grass tetany is a nutritional or metabolic condition in beef cattle and sheep triggered by low amounts of magnesium (Mg) in the blood serum. This disorder occurs most frequently in the spring when livestock graze young, succulent, cool season grasses. It intensifies in warm periods, five to 10 days after a cool, wet period when grass is growing rapidly. Although it is less prominent, grass tetany can also occur in the fall when regrowth of cool season grasses occurs. What causes grass tetany? Factors that can increase the occurrence of grass tetany in livestock include stress, drought, diets low in Mg and phosphorous (P), diets with nutrient imbalances that interfere with Mg metabolism, high levels of nitrogen (N) or potassium (K) in feed or soils, increased Mg demand during lactation, minimal availability of standing dead forage, and forages with a “tetany ratio” {K/(Calcium + Mg)} of greater than 2:2. Because it is a function of soils, plant species, harvested feed, environmental fac
