Comparison of the total antioxidant capacity (TAC) level in plasma of dairy cattle in relation to number of parturient

Free radicals can be produced during the respiratory oxidation of different cells.these free radicals can damage to various macromolecules as protein, fat, nucleic acids and…,are harmful for body. The natural defence system that can prevent the damage of free radicals and nuteralize them, have tittled under the name of total antioxidantcapacity (TAC) and probably can change in some stress conditions such as number of parturient. In this respect,we have determined 100 dairy cattle(1 week before and aftercalving) and measured plasma TAC levels in them by ferric reducing ability of plasma (FRAP) method. The results were analyzed by ANOVA_test and siginificantdifference was shown between TAC levels of parturation number 4 and 5 with (p<0.001).also in each parturitionplasma TAC level decreased in after calving to comparebefore same Calving. Vet. Res. Bull. 6,1:19-22,2010.Keywords: TAC,calving,cow