[Relevance, measurement and assessment of the antioxidative status in farm animals]

Reactive oxygen species (ROS) are generated in living organisms under physiological and pathological conditions. They have to be neutralized by the antioxidative system which consists of enzymatic and non enzymatic antioxidants. Both, the activity of antioxidative enzymes and the capacity of non enzymatic antioxidants are known as the antioxidative status of the organism. If the balance between prooxidative processes and antioxidative system is disturbed oxidative stress occurs. Oxidative stress is considered to be a major risk factor for the reduction of defence mechanisms and development of diseases. The aim of the present work is to describe various aspects of the antioxidative status in several production animal species. Conclusions for management and therapy are drawn when possible. Furthermore the paper provides an overview of methods for assessment of antioxidative metabolism. Farm animals undergo several periods of severe challenge of the antioxidative system during the production cycle. Especially young animals in the first weeks of their life and animals during the periparturient period are at high risk. High yielding live stock generally have to carry a higher oxidative burden in comparison to animals which are on a medium production level or in extensive systems. Other risk factors are unsuitable or spoiled components in the diet and heat stress. Exogenous antioxidant supply can be optimized by feeding fresh roughage or silage of good quality or if necessary by using additives. Changes of the antioxidative system have been described in association with displaced abomasum (DA), abomasal volvulus (AV) and reproductive problems in swine. Pre- and postoperative supplementation of antioxidants has been used with good results as supportive treatment in therapy of cattle with DA.