Effects of antioxidants in fat contained in bulky forages on cows' milk quality

Abstract

Antioxidants contained in bulky forages, i.e. Tocopherols and carotenoids, play a significant role in meeting the demand for carotene, and vitamins a and e in dairy cows. This paper is a review of the results of some scientific research carried out during the last decade in order to study the impact of natural antioxidants in fat contained in bulky forages on the oxidative status of milk as well as on the content of functional components in milk. Based on the research results analyzed, it is possible to manufacture milk with an increased content of unsaturated fatty acids and antioxidative substances (vitamins a, e, and β-carotene), provided, however, that the cows are fed forages with a high content of carotenoids and tocopherols. The antioxidants as named above protect the unsaturated fatty acids contained in the milk fat from adverse oxidation processes, and, at the same, they retain their high biological activity and a proper taste and odour of milk. The content of carotenoids and tocopherols in bulk forages, as well as the rate of their transfer into milk depend crucially on the following: species and variety of plants, stage of vegetation, agrotechnical measures applied, weather conditions during the vegetation period, and forage conservation methods (such as drying or silage). Green fodders and silages from vegetative meadow covers, papilionaceous plants, and mixtures of grasses and papilionaceous plants should be maximally utilized in feeding dairy cows as a valuable source of vitamins a, e, and β-carotene, since they, together with the unsaturated fatty acids, beneficially impact the quality of milk and consumers' health.