Heavy Metals in Fluids and Tissues of Fetal Calves and in Young Calves of Nursing Cows Exposed or Not Exposed to Anaerobically Digested Wastewater Sludge

Fetal fluid, diaphragm muscle, heart, kidney, and liver from 14 four- to five-month-old calf fetuses were analyzed for Zn, Cu, Cd, Cr, Ni, Pb, and Fe. The same tissues and bone were examined from postparturient calves 30, 60, and 120 days of age. Weaned calves (8 to 9 months old) were necropsied and diaphragm muscle, heart, kidney, liver, brain, and bone were analyzed. Additional calves from cows exposed or not exposed to anaerobically digested sludge were placed in a feed yard at weaning for a feeding period of 150 days and then were killed and necropsied. Heavy metal content of the aforementioned tissues was compared with the same tissues obtained from peer calves weaned, killed, and necropsied 150 days earlier. Zinc, Cu, and Fe were up to 11 times higher in fetal livers than in control or exposed postparturient calves. These concentrations declined after birth and stabilized at approximately the concentrations observed in adult cattle at about 12 to 14 months of age. Cadmium accumulated to a greater extent in kidneys and livers of exposed calves than in control calves. However, the accumulation did not produce a detectable effect upon the functional or morphologic characteristics of the organs examined. Other metals were present at low levels and were generally not remarkably different in control and exposed animals.