Grass tetany (hypomagnesemia) causes sudden death in cattle after a brief period of severe neurological signs, with prevention through magnesium supplementation being effective and critical.
Grass tetany causes extreme acute suffering. The convulsions and tetanic spasms experienced during a grass tetany crisis are agonizing. The rapid progression from apparent health to severe neurological crisis and death within an hour means welfare intervention must be immediate. Many cases are found dead without any observed crisis period. For cows observed during the crisis, the distress is extreme and the window for treatment is narrow. Prevention through appropriate magnesium supplementation during the at-risk spring period is straightforward and highly effective, making grass tetany deaths preventable welfare failures.