Lead Poisoning in Cattle and Horses Following Long-Term Exposure to Lead

Abstract

SUMMARY Lead poisoning involving deaths in cattle and horses occurred in the vicinity of industrial lead operations. Pastures and crops were contaminated by fumes and dust emitted from lead industries that settled out on the surrounding countryside. Horses appeared more susceptible than cattle to poisoning by the chronic ingestion of lead. Whereas horses exposed to an estimated daily intake as low as 1.7 mg./kg. (approx. 80 p.p.m. (dry weight) in forage) were poisoned, a similar intake in cattle did not produce observable ill effects. Clinical signs of lead poisoning occurred in cattle with a daily intake of 6 to 7 mg. lead/kg. of body weight. It is unlikely that cattle or horses would eat sufficient quantities of roadside grass contaminated by lead fallout from automotive exhaust to result in clinical lead poisoning. Human beings residing in areas where aerial fallout from industrial lead operations has resulted in lead poisoning in cattle and horses have not shown evidence of increased lead absorption.