Determination of Cesium-137 and Related Sampling Problems of Dairy Cattle Feeds, 1962-1967
Abstract Samples of feeds fed to dairy cattle on the university farm were analyzed from 1962 to 1967 for fallout 137Cs by means of gamma-ray spectrometry. Maximum levels were observed in first-cutting alfalfa hay in 1963 (3600 pc/kg).Second and third cuttings each year were lower by factors of two to six. Levels declined each year after 1963 to barely detectable levels in mid-1967. Pasture forage or green-cut alfalfa contained concentrations of 137Cs similar to hay with the same seasonal and yearly patterns. Corn silage contained levels similar to later cuttings of hay. Grain mixes contained levels which were lower than forages by a factor of 10 in 1962-1963 but approached equal levels in subsequent years. The results indicated that sampling was much more important than radiation counting in explaining variation between sampling. The levels of 137Cs found in the feeds was readily explained in terms of observed patterns of fallout during this period.
