Slowed Learning in Lambs Prenatally Exposed to Lead

Abstract

Two groups of ewes were given lead sufficient to maintain mean blood lead levels of 34μg/100 ml (fed 4.5 mg/kg lead/day) and 18μg/100 ml (fed 2.3 mg/kg lead/day), respectively, throughout gestation. Lambs from the two lead-exposed groups and from control ewes had blood lead levels of 24μg, 17μg, and 6μg/100 ml, respectively, at 2 to 4 weeks of age. Between 10 and 15 months of age, the lambs prenatally exposed to maternal blood lead levels of 34μg/100 ml required significantly more days to learn visual discrimination problems, while lambs exposed to maternal blood lead levels of 17μg/100 ml did not differ from the controls.