Factors Affecting Iodine Concentration in Bovine Milk

Abstract

The purpose of this study was to investigate the effect upon the secretion of iodine into cows’ milk of various compounds demonstrated to alter thyroid function. Nine cows were given radioiodine twice daily to achieve a steady state condition. After a control sampling period the cows were given KClO4, NaI, NaCl, and l-thyroxine, d-thyroxine, or 2-4 dinitrophenol. KClO4, NaI, NaCl, and l-thyroxine reduced the accumulation of radioiodine in milk and reduced the milk-I131/plasma-I131 ratio; whereas, d-thyroxine and 2-4 dinitrophenol did not. l-thyroxine, although probably acting directly upon the mammary gland, was limited in its ability to reduce I131 accumulation in milk. It was concluded that transfer of iodide into milk was in part an active process and that thyroxine could affect the transfer of iodide from plasma to milk and from milk to plasma. © 1965, American Dairy Science Association. All rights reserved.