Element Before calving Before calving Top of lactation n=60 n=60 n=60 Cu Mean 16.80 17.07 16.96 SD 3.22 4.64 2.80 Zn Mean 29.25 26.90 26.55 SD 10.65 9.44 9.40

Table 1: The concentration of Cu and Zn in blood serum (μmol/L) of dairy cows from western Slovakia.