Oxidative stress and imbalance of mineral metabolism contribute to lameness in dairy cows.

The objective of this study was to investigate correlations between oxidative stress, metabolism of mineral elements, and lameness in dairy cows. Forty multiparous Chinese Holstein dairy cows were selected and divided into two groups (healthy vs lame, n = 20) by gait score. The experiment lasted for 60 days and samples of hair, blood, and hoof were collected at days 0, 30, and 60 of experiment period, individually. Compared with healthy cows, elevation of MDA, CTX-II, COMP levels, and GSSG/GSH ratio together with depletion of SOD and MT levels in the serum were revealed in lame cows. Simultaneously, significant decreased contents of Zn, Cu, and Mn in the serum, hair, and hoof samples were shown in lame cows, but there was no obvious difference in contents of P, Mg, and Ca (except hoof Ca) in the serum, hair, and hoof between healthy and lame cows. In addition, histological examination and the hardness test demonstrated a poor hoof quality in lame cows. In summary, oxidative stress is implicated in the pathogenesis of lameness caused by imbalance of nutrients (especially selective minerals promoting healthy hoof growth) in dairy cows.