Beef

Relative Bioavailability of Supplemental Cu Sources as Determined in Growing Steers Fed a High Antagonist Diet

Authors: Stephanie L. Hansen (Iowa State Universtiy) , Katherine VanValin (Iowa State University) , Olivia Genther-Schroeder (Purina Animal Nutrition Center)

Abstract

The objective of this study was to evaluate the relative bioavailability of an organic Cu source, Cu lysine and a hydroxy Cu source, basic Cu chloride, relative to an inorganic Cu source, CuSO4. Although initial liver Cu concentrations were similar across all treatments, final liver Cu concentrations were lesser in those cattle receiving 0 ppm vs. 5 or 10 ppm of supplemental Cu. This is to be expected when feeding a diet supplemented with the Cu antagonists S and Mo. However, steers receiving 0 or 5 ppm supplemental Cu had liver Cu concentrations that were either deficient or marginally deficient, regardless of source. This suggests that in cattle consuming high antagonist diets, 10 ppm of supplemental Cu is necessary to maintain liver Cu status. The relative bioavailability of basic Cu chloride tended to be greater (112%) compared to CuSO4, while the relative bioavailability of Cu lysine was similar to that of CuSO4 as determined by liver Cu concentrations. Ultimately, when fed in high antagonist diets basic Cu chloride may be more bioavailable to the ruminant animal then CuSO4.

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How to Cite: Hansen, S. L. , VanValin, K. & Genther-Schroeder, O. (2019) “Relative Bioavailability of Supplemental Cu Sources as Determined in Growing Steers Fed a High Antagonist Diet”, Iowa State University Animal Industry Report. 16(1).