Grass tetany

March weather has taken us on a wild ride. I rolled up my shirt sleeves as pasture grasses greened up and grew two inches higher last weekend. A few days later the mercury plummeted and February's cold, bitter winds blew through the barn as I busted ice for the dairy goats. Typical March. Pastures are greening up quickly on days it is not snowing and cattle are chomping at the bit to begin the grazing season. 'Tis the season to shore up fences and take precautions against grass tetany. Grass tetany is an often-fatal metabolic disorder associated with low magnesium levels in the blood stream. Early pasture growth is almost exclusively grass as legumes such as clover require warmer soil temperatures before breaking dormancy. Fast-growing grasses are often magnesium deficient which can lead to grass tetany. Cattle store magnesium in their bones and muscles, but it passes quickly through urine, manure and milk. Older cows nursing calves during late winter and early spring are most susceptible but all classes of cattle are at risk. Keep a close watch on cows in peak lactation who are losing considerable magnesium through milk production. Animals suffering from grass tetany are often found dead, signs of leg paddling may be evident in some cases. Early signs include excitability with muscle twitching, exaggerated awareness, and a stiff gait. Some animals appear aggressive, bellowing and galloping followed by staggering while others may exhibit a change in character and/or difficulty in handling. If you suspect grass tetany call a vet immediately. Prevention and control of grass tetany is more successful than treatment. First, increase energy and roughage intake – feed good quality hay. It's easy to think "they've got a little grass, they can eat the poor hay." Feed your best hay now, particularly to late gestation and lactating cows. Delay turnout until Tall Fescue reaches 10 inches tall if at all possible. Next, supplement with magnesium in the form of magnesium oxide or magnesium sulfate. Loose minerals are preferred over blocks. Keep a high-mag mineral supplement available until the danger of grass tetany has passed, typically late spring, but monitor consumption. Cattle require 0.6 oz of magnesium daily. If your cattle are not consuming adequate amounts via loose mineral, supplementation with cereal grains or commercial feed containing additional magnesium may be necessary. In no situation is the old adage "an ounce of prevention is worth a pound of cure," truer than when dealing with grass tetany. In the rush up to spring and turn-out, invest in your herd's health and save yourself some grief by providing high-mag mineral supplements for the next few weeks.