Relationships between trace elements, oxidative stress and subclinical ketosis during transition period in dairy cows

The possible relationships between trace elements, oxidative stress and subclinical ketosis during the transition period were evaluated in dairy cows. Blood samples were obtained by jugular venipuncture at four times of the transition period: 3 weeks and 1 week before and 1 week and 3 weeks after calving. The highest concentrations of malondialdehyde (MDA) and betahydroxybutyrate (BHB) were observed on the week 1 after calving. In contrast, the serum values of copper, zinc, albumin, uric acid and TIBC decreased after calving. After calving, zinc concentration showed a significant negative correlation with MDA concentration (p