Nickel in Cows’ Milk

Abstract

Nickelous chloride was fed as a supplement (500 mg. daily) to the rations of 6 cows for a period of 2 months by the double reversal method and the milk was analyzed for Ni. Although varying amts. of Ni were found in the numerous milk samples taken, it was shown that when the milk was kept from contact with metal by milking directly into glass jars, Ni was not present. It was therefore concluded that Ni is not a constituent of natural milk and that the varying amts. found in the course of the investigation came from the milking machine. The difference in this respect between Co and Ni, 2 closely related elements, is discussed briefly.