Vitamin E in dairy cows

During the past two decades significant advances have been made in understanding the importance of an adequate vitamin status in dairy cows based on improved nutrition. These progresses have substantially re-defined the meaning of vitamins as essential signalling molecules or cofactors that allow animals to sustain health and production. For this reason the concept of optimum vitamin requirements for animals under intensive livestock conditions has been developed. The intensive research interest in vitamin E stems from its potential role as an antioxidant that is able to prevent free-radical mediated tissue damage. Vitamin E also seems to be crucially involved in immune system function, so that supplementation with supra-nutritional levels of the vitamin, in some instances, results in improved immune responses. This article will provide an overview of current knowledge of vitamin E in dairy cows, including an assessment of lesser known and still only partially elucidated effects on efficiency of absorption and transport to target tissues, and uptake and function at the cellular and molecular levels. (c) 2005 Elsevier B.V. All rights reserved.