Unexpected outcome after two consecutive infusions of disodium EDTA in dairy cows.

Disodium ethylenediaminetetraacetic acid (Na2EDTA) is a cation chelator which is used as an anticoagulant in blood samples and as a therapeutic agent in lead poisoning. Several experiments have been carried out with EDTA to induce hypocalcemia in cows and other animals, and toxic effects have rarely been reported. In this study, hypocalcemia was induced by means of a 5% Na2EDTA infusion (0.55 mg/kg/min Na2EDTA for 5 h = total dose of 100.6 g). Accidental acute toxicity and fatalities occurred after a consecutive second infusion in several cows. Researchers designing new experiments should be aware of a potential EDTA toxicity at a routinely used dose and rate of administration.