Ingested soil as a source of microelements for grazing animals

Two sheep were drenched each with 100 g of soil containing approximately 1 mc each of 60 Co, 54 Mn, 7BSe, and 65 Zn. Activities of these isotopes in blood, urine, and faeces were monitored at intervals over a 10-day period by gamma-ray spectroscopy. At the end of this period the animals were killed and a range of hard and soft tissue samples was taken for analysis. From the data obtained on blood and tissue samples taken at time of death, and from urine samples over the 10-day period, amounts of isotopes absorbed by the animals and amounts of isotopes originally held on the ingested soil were compared. The amounts of the isotopes absorbed by the animals from the soil, expressed as a percentage of an isotope held on the soil, were approximately: 75 Se, 34 percent; 65 Zn, 14 percent; 60 Co, 1 percent; 54 Mn, 0.4 percent.