This study was performed to determine the effects of species and sexes on antioxidan enzymes of erytrocyte and lipid peroxidation of plasma in ruminants. In the present study, the activities of glutathione peroxidase (GSH-Px) and catalase (CAT) that play role in the free radical metabolism in erythrocytes, and plasma MDA levels of clinically and postmortem healthy ruminants being bred in Elazığ province were measured.

Compared between species and inside species, it was found that species and sexes of animals have effection on these parameters in different degrees. Cattle had the greatest CAT (96.22±2.16 1x10⁴ U/g Hb) activity, whereas goats had the greatest MDA (3.54±0.12 nmol/plasma) plasma concentration.

In comparison of male and female, erythrocyte activity in cattle was higher in males, whereas erythrocyte CAT activity was found to be greater in females. Female goats had significantly higher GSH-Px and CAT activities. Erythrocyte CAT activity of rams was greater than other sex.

Discrepancy of antioxidant levels between species and sexes may depend on to the differentiation in oxidant damage mechanism of cattles, sheep and goats or existance other endogen antioxidant in these animals.