Fallout Radioactivity in Cattle and Its Effects

The levels of strontium-90 and cesium-137 in cattle grazed on the Nevada Test Site and elsewhere in Nevada are similar to those in cattle from other parts of the country. Gastrointestinal absorption of the relatively large amounts of radioactive cerium-praseodymium, ruthenium-rhodium, and zirconium-niobium present in the rumina is very small. Zinc-65 made its first appearance in samples of muscle and liver in November 1958 and has persisted in later samplings. There has been no evidence of biological damage to date, either histologically or grossly.