Radioactive cattle

There is no available experimental data on the effects of feeding cattle radioactive particles to a level that could cause significant damage to their gastrointestinal tract. The existing data on ruminants, obtained from a study mentioned in NAS-NRC (1963), used low levels of B0Y as tracers in goats. The data on dosimetry (radiation exposure) in dogs and laboratory animals are unlikely to be relevant to grazing livestock. Various factors need to be considered in studies on ingestion, such as the direct retention of radioactive fallout by pasture forages, the dust that settles on the forages (as noted in Ward and Johnson, 1966), rain splashes, and the level of grazing. Ruminants grazing under ideal conditions consume about one percent of their dry-matter intake in soil, whereas in overgrazed pastures, soil ingestion may amount to around four percent of the dry-matter intake (Field, 1964; Mealy and Ludvig, 1965). In the case of swine and poultry, who primarily rely on supplemental grains, their ingestion of contaminated soil would be much smaller.