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<0.005). the concentrations of mda after calving showed a positive correlation with bhb (p<0.005), while zinc showed a negative correlation with bhb at this time (p<0.05). the results of logistic regression test showed that the decreased concentration of zinc in the weeks 1 before and week 1 after calving was associated with the probability of occurrence of subclinical ketosis. moreover, an increase in mda concentration at the week 1 after calving was associated with the risk of subclinical ketosis. the results of the present study showed that cattle with insufficient concentrations of trace elements are prone to oxidative stress and cattle with increased oxidative stress may be subclinical ketosisprone.