Which mineral disturbance is most classically associated with milk fever in dairy cattle?

• A. Hypocalcemia
• B. Hypercalcemia
• C. Hypomagnesemia
• D. Hyperphosphatemia

Answer: (A)

Milk fever arises when a dairy cow near calving loses the ability to meet the sudden calcium demand for milk production. If calcium intake and bone reserves can’t keep up, blood calcium falls, producing the classic signs of weakness and reluctance or inability to rise. This drop in calcium is called hypocalcemia, and it’s the hallmark feature of milk fever.

Hypercalcemia would be the opposite situation and isn’t associated with milk fever. Hypomagnesemia causes a different problem (often tetany with nervous signs) and isn’t the classic disturbance of milk fever. Hyperphosphatemia can accompany low calcium in some tests, but it isn’t the defining disturbance of this condition.