Background of the copper and zinc requirement for dairy cattle, growing-finishing pigs and broilers

Re-evaluation of the current authorized levels of Cu and Zn in animal rations has been initiated by the European Union (EU). The physiological requirements should be the basis for the future maximum authorized dietary levels for minerals in the EU, resulting in lowering of these maximum levels. Based on an earlier study, the basis of the recommendations for Cu and Zn of dairy cattle, growing pigs, and broilers as used by different countries seemed to be questionable. These recommendations are based on research at relatively low animal production levels as compared with the current Dutch situation. Therefore, a survey of the scientific literature underlying the recommendations of ARC, NRC, DLG, COMV, and INRA was carried out, together with other reports on dietary Cu or Zn requirements of the animal categories mentione