Winter Tetany – Frequently Asked Questions
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What is Winter Tetany?
Winter tetany is a metabolic condition caused by lower than average blood magnesium (Mg) levels. This condition occurs when cattle consume poor quality hay or straw, that contain low levels of magnesium, or good quality cereal greenfeed or silage with high levels of potassium (K). High levels of potassium in the diet reduces the absorption of magnesium and calcium (Ca). Cattle depend upon a continual daily supply of magnesium and calcium from the digestive tract to maintain normal blood concentrations. Often in Alberta winter tetany is associated with feeding grain and straw or greenfeed based rations that contain low or borderline calcium and magnesium, and high potassium levels compared to the cow’s requirements.