RESUMO
OBJECTIVE: To evaluate clinical findings in cows with recumbency associated with hypokalemia. DESIGN: Retrospective case series. ANIMALS: 10 adult dairy cows with weakness or recumbency and hypokalemia. PROCEDURE: Signalment, history, physical examination findings, results of diagnostic tests, and response to treatment were extracted from the medical record of each cow. RESULTS: 8 cows were recumbent on admission and 2 were profoundly weak. All cows had been given isoflupredone acetate as treatment for ketosis prior to admission. All were hypokalemic (serum potassium concentration, 1.4 to 2.3 mEq/L) with no other apparent cause for recumbency. Despite treatment with potassium, plasma potassium concentrations within the reference range were achieved in only 6 of the 9 cows treated. Two cows responded to treatment. Three cows died, 3 were euthanatized, 2 improved clinically and were discharged, 1 was discharged while still recumbent, and 1 was sent to slaughter prior to treatment. Histologic examination of muscle tissue from 2 cows revealed myonecrosis and vacuolation consistent with hypokalemic myopathy. CLINICAL IMPLICATIONS: Hypokalemia should be considered in the differential diagnosis for cows that are weak or recumbent, particularly after treatment for ketosis with isoflupredone acetate. Aggressive treatment with potassium salts administered orally is indicated.
