Influence of Injection of Cows with Copper Glycinate on Blood and Milk Copper and Oxidized Flavor in Milk

Abstract

Summary Subcutaneous injection of copper glycinate suspension into a cow causes prolonged elevation of blood copper. It was postulated that if the elevated blood copper increased the milk copper level, the treatment might provide both an experimental approach to studying factors that influence the concentration and catalytic activity of natural copper in milk, and a source of milk that would develop spontaneous oxidized flavor consistently. Subcutaneous injection of three cows with 300mg of copper as copper glycinate suspension increased both blood and milk copper for at least 4 wk but, except during the first 24 hr after injection, did not increase the incidence of spontaneous oxidized flavor in the milk. The low catalytic activity of the copper suggests that it was bound in a different form from that in normal milk produced after the first 6 to 8 wk of lactation. Since the metabolism of copper is influenced by molybdenum and zinc, these elements were determined spectrographically in the blood and milk. After the copper glycinate injections, molybdenum and zinc were higher in the blood but not in the milk.