Evaluation of oxidative and an­tioxidant status in dairy calves before and after weaning

Abstract

Weaning is a stressful step in calf rearing which can lead to oxidative stress. The purpose of the present study was to investigate oxidative stress and antioxidant status in calves pre and post weaning. A total of 22 clinically healthy female Holstein calves at the same age were selected and their blood samples were examined to measure the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) in red blood cells and serum malondialdehyde (MDA) concentration. Sampling was performed in 4 consecutive stages: 7 days pre-weaning, the day of weaning, 24 and 72 hours after it. The results indicated that the activity of SOD and GPx enzymes increased significantly on the weaning day compared to the previous week. CAT activity increased 24 and 72 hours after weaning and its increase was significant 72 hours after weaning compared to the day of weaning. An increase was observed in MDA level on the day of weaning compared to a week before, and the trend was towards increase after the weaning. Weaning stress leads to disturbances of oxidative system balance and causes oxidative damage in calves. This imbalance can be probably resolved by improving the antioxidant system and supplementing antioxidants such as vitamins E and C against free radicals produced during weaning.