Supplemental selenium reduces the levels of biomarkers of oxidative and general stress in peripartum dairy cows.

The aim of this investigation was to determine the influence of oxidative stress upon general stress in dairy cows on parturition and whether the indicators of stress can be reduced by selenium (Se) supplementation. A total of 36 animals were divided into 3 groups 21 days prepartum and treated with a single-term intra muscular supplement of sodium selenite: Control group - 0 mg; group Se10 - 10 mg; group Se20 - 20 mg. Se supplementation significantly raised blood Se content and glutathione peroxidase (GPx) activity in groups Se10 and Se20, compared to Control, although there was no marked difference between supplemented groups. Plasma malondialdehyde (MDA) and cortisol concentrations were significantly reduced in supplemented groups Se10 and Se20, compared to Control. A negative correlation was detected between blood GPx activity and plasma MDA, while a positive correlation was determined between plasma MDA and cortisol concentrations. These results indicate that prepartum Se supplementation can be utilized for a partial relief of stress in cows during labor by augmenting the antioxidative action of GPx.