Transfer Coefficients of Fallout Cesium-137 to Milk of Dairy Cattle Fed Pasture, Green-Cut Alfalfa, or Stored Feed1,2

Abstract

The transfer coefficient (per cent intake per liter of milk) of fallout 137Cs was measured in the University herd under three feeding conditions. Groups of about ten Holstein cows were pastured for three summers and received supplemental alfalfa hay and grain. The entire University herd of about 100 cows of four 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 was found to average 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.