Abstract
SIXTEEN bull calves were fed a 70% concentrate diet containing no added lead, 10 ppm lead from newsprint, or 10 and 100 ppm lead from lead chromate. The diets were pelleted and fed ad libitum for 100 days. Fecal and urine samples were collected and EKG and respiration rates were monitored at 25-day intervals. At the end of the 100-day feeding trial, the calves were sacrificed and samples of skeletal muscle, cerebral cortex, liver and kidney were collected for lead analysis. Supplemental lead did not affect feed consumption nor weight gain; however, newsprint depressed both intake and gain. Neither EKG patterns, heart rate nor respiration rate were affected by dietary treatment. The percentage of ingested lead excreted in feces and urine was not significantly different among treatments. There were no significant tissue accumulations of lead from feeding newsprint or 10 ppm lead chromate; however, feeding 100 ppm lead chromate resulted in accumulations of the element in liver and kidney. Samples of cerebral cortex, liver and kidney cortex were examined by electron microscopy. Changes were not detected in the cellular ultrastructure of these tissues from either control or treated animals. Copyright © 1973. American Society of Animal Science . Copyright 1973 by American Society of Animal Science.