Transfer Coefficients of Fallout Cesium-137 to Milk of Dairy Cattle Fed Pasture, Green-Cut Alfalfa, or Stored Feed

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Abstract
The transfer coefficient (per cent intake per liter of milk) of fallout 137Cs was measured in the Colorado State University herd under 3 feeding conditions. Groups of about 10 Holstein cows were pastured for 3 summers and received supplemental alfalfa hay and grain. The entire University herd of about 100 cows of 4 breeds was studied during the winter feeding period, when they received alfalfa hay, corn silage, and a grain mix. Eight Holsteins were fed alfalfa cut daily, together with small amounts of hay, and grain according to production. All 137Cs demonstrations were made by gamma-ray spectrometry. The transfer coefficient averaged 0.35 under pasture feeding conditions during the summers of 1962, 1963, and 1964. A mean of 0.41 was found during the winter feeding period of 1963, and a value of 0.25 when green-cut alfalfa was fed in the summer of 1965. The range in values was lowest for the dry-lot trial in which no breed effect was evident. Within treatments the level of crude fiber intake was not related to transfer coefficient.