Lead poisoning and toxicokinetics in a heifer and fetus treated with CaNa2 EDTA and thiamine.

Lead (Pb) poisoning of a pregnant heifer was diagnosed based upon clinical signs (head pressing, blindness, muscle twitching) and a blood lead concentration of 1.73 ppm. Blood and urinary Pb half-lives with CaNa2 EDTA/thiamine therapy were determined to be 2.08 and 1.38 days, respectively. Many cations (Ca, Fe, Zn, Na, Cu), including Pb, were excreted at higher concentrations in urine during therapy. Blood (0.425 ppm) and liver (4.85 ppm) Pb concentrations in the fetus were 71.7% and 84.3% of the same tissue Pb concentrations of the dam, indicating a significant transfer of Pb in utero. Severe polioencephalomalacia was described in the adult, and hepatic lysosomes with metallic electron densities were present in the fetus.