Enhanced erythrocytic lipid peroxides and reduced plasma ascorbic acid, and alteration in blood trace elements level in dairy cows with mastitis.

Oxidative stress has been associated in several inflammatory conditions and incriminated in the pathogenesis of many diseases. However, little information is available on the status of plasma antioxidant levels, essential components of important antioxidant enzymes such as copper, zinc and selenium in blood, and the end product of oxidative damage to the erythrocytic polyunsaturated fatty acids in inflammatory udder conditions. Blood samples were collected from three groups of dairy cows, with 21 in each group: animals with healthy udder, clinical mastitis, and subclinical mastitis. These animals were randomly selected from a herd on the basis of the California mastitis test, somatic cell count and total bacterial count. The mean plasma ascorbic acid concentration was significantly lower in cows with subclinical (p = 0.004) and clinical mastitis (p = 0.000) and the erythrocytic lipid peroxide levels were significantly (p = 0.000) higher in clinical mastitis as compared to controls. There was a significant decrease in mean blood zinc concentration in subclinical (p = 0.005) and clinical mastitis (p = 0.000), but an increase in mean blood copper level in the clinical mastitis group. It was concluded that the blood antioxidant status declines in inflammatory udder conditions, suggesting that incorporation of antioxidants may help in better management of mastitis in dairy cows.