Grass Tetany

In 2005, the United States experienced a 7% loss of beef cattle from death that was caused by digestive problems. Digestive problems can easily be related to mineral imbalances or sudden shifts in cows diets. Such as a high roughage to a high concentrate. Grass tetany, milk fever, water belly, polioencephalomalacia and white muscle disease are associated with mineral imbalances.

Grass Tetany or sometimes better known as hypomagnesaemia, is a nutritional disorder found in cattle with low levels of magnesium or calcium. Typically caused by grazing cool-season perennial grasses in spring or winter that have rapid and lush growth. Grasses often associated with grass tetany include rye grass, wheat, oats or other small grains. Lactating cows or cows with calves that are under the age of 2 months are frequently affected by grass tetany.

Grass tetany results when forages don't meet the requirements of magnesium and calcium to cattle's diets. Proper diagnosis of grass tetany can be difficult because the symptoms resemble many other diseases. However, a positive diagnosis can be confirmed by a blood test. Tetany symptoms include; nervousness, muscle twitching and staggering during walking, excitable, uncoordinated, and grinding teeth. Or expressing a wild stare with erect ears and appear to be blind. These can be followed by convulsions that can be violent, a deep coma, and then death.

With effort, grass tetany is preventable. Magnesium-deficient pastures can be limed with a dolomitic lime that contains magnesium. Fertilization of phosphorus can also be useful for improving magnesium forage levels. The planting of legumes like alfalfa, lespedeza or clovers, can help reduce the risk of tetany when included in forage production because they are high in magnesium. Although fertilization and planting of legumes can help reduce the risk of tetany, the most reliable method of prevention is supplementing magnesium and calcium during the grass tetany season, fall and spring.

Cattle that have collapsed and have been down for more than 12-24 hours will seldom ever recover. However, blood magnesium levels are able to be increased within 15 minutes by administering 500 ml of a calcium borogluconate solution that contains a 5% magnesium hypo phosphate. Respiratory rates and heart should be monitored during administration. Animals should be handled gently to prevent excitement. Farmers could also give 200 cc of sterile solution of magnesium sulfate (Epsom Salts) injected under the skin at least four different sites.

Sources:
Field, Thomas G. Beef Production and Management Decisions. Ed. Vernon Anthony and Jill-Jones Renger. 5th ed. Columbus: Pearson Prentice Hall, n.d. Print. 

Gadberry, Shane, and Jeremy Powell. Nutritional Disorder in Beef Cattle. N.p.: University of Arkansas Cooperative Extension Service, n.d. Print. 

Parish, Jane A., and Justin D. Rhinehart, Dr. Beef Cattle Nutritional Disorders. N.p.: Mississippi State University Extension Service, 2009. Print.