Cornell University: Grass Tetany in Cattle

For early calving herds, the risk of tetany may be low, but for those that are calving or will soon be, now is the time to consider how to manage this deficiency, which can lead to death.

The ConditionLow blood magnesium (hypomagnesemia) is a complex metabolic condition aggravated by stresses such as lactation, weather, fatigue or excitement. Consumption of forages such as lush grass pastures or green cereal crops (cover crops) in which magnesium is low can reduce blood magnesium and precipitate the highly fatal crisis called tetany. Adult lactating animals are most susceptible because of the loss of Mg in milk and their inability to mobilize Mg bone reserves. Tetany usually occurs near parturition and/or until approximately 2 months postpartum, and the frequency usually increases with older cows. It is rare in non-lactating animals unless they were undernourished and turned into lush pasture or a green cover crop. Cool, rainy weather can increase the incidence of this disease.

Fact sheet.


By Brian Allmer - The BARN

Brian Allmer & the BARN are members of the National Association of Farm Broadcasting (NAFB), the Colorado FFA Foundation, the Colorado 4H Foundation, the Colorado Farm Show Marketing Committee, 1867 Club Board Member, Denver Ag & Livestock Club Member, the Weld County Fair Board, the Briggsdale FFA Advisory Council, Briggsdale 4H Club Beef Leader & Founder / Coordinator of the Briggsdale Classic Open Jackpot Show.