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Fatty acid, tocopherol and carotenoid content in herbage and milk affected by sward composition and season of grazing

Larsen, Mette K, Fretté, Xavier C, Kristensen, Troels, Eriksen, Jørgen, Søegaard, Karen, Nielsen, Jacob H
Journal of the science of food and agriculture 2012 v.92 no.14 pp. 2891-2898
Trifolium pratense, Trifolium repens, carotenoids, conjugated linoleic acid, dairy cows, fatty acid composition, feeds, forage, linolenic acid, lipid content, milk, milk fat, milk production, milk quality, multivariate analysis, sward
BACKGROUND: The aim of the present work was to study to what extent grazing large amounts of white clover (WCL), red clover (RCL), lucerne (LUC) or chicory (CHI) was suitable for production of bovine milk with a high milk fat content of tocopherols, carotenoids, α‐linolenic acid and conjugated linoleic acid. RESULTS: WCL, RCL, LUC and CHI swards were established to investigate the influence of herbage composition on the milk quality of grazing dairy cows at three periods. Average milk fat composition showed high concentrations of linolenic acid (12 mg g−1), conjugated linoleic acid (13 mg g−1), carotenoids (6 µg g−1) and α‐tocopherol (21 µg g−1 milk fat). There were minor differences between herbage types and periods, but multivariate analysis of these data showed no clear grouping. Chemical composition of herbage varied with species as well as period, but it was not possible to relate milk and feed contents of specific fatty acids, carotenoids or tocopherols. CONCLUSION: All four herbages tested were suitable for production of milk with a high content of beneficial compounds. Thus any of these herbages could be used in production of such differentiated milk based on a large proportion of grazing in the ration.