SHARING OPTIONS: Spring is a period when weather can be extremely variable, putting suckler cows sucking a calf at a higher risk of grass tetany. Changeable weather is forecast for the week ahead and this will increase the risk of grass tetany in spring-calving cows that are suckling calves at grass. Herd owners should be keeping a close eye on lactating cows for early signs of tetany. But by following these five steps, the risk posed to cows is greatly reduced. Magnesium supplementation Providing cows with supplementary magnesium is the most common method of preventing tetany on suckler farms. There are various forms of magnesium supplementation on the market and there are pros and cons to them all, depending on cost, practicality of using them and how long they provide cover for.