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Effects of clover-grass silages and concentrate supplementation on the content of phytoestrogens in dairy cow milk

Steinshamn, Håvard; Purup, Stig; Thuen, Erling and Hansen-Møller, Jens (2008) Effects of clover-grass silages and concentrate supplementation on the content of phytoestrogens in dairy cow milk. Journal of Dairy Science, 91, pp. 2715-2725.

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Online at: http://jds.fass.org/cgi/content/abstract/91/7/2715

Summary

A 2 × 2 factorial continuous experiment was conducted with 28 Norwegian Red dairy cows in early lactation to compare milk content of phytoestrogens when feeding ad libitum white clover (WCS) or red clover (RCS) grass silages prepared from the second and third cut without and with 10 kg/d supplementation of a standard concentrate. The cows were offered either RCS or WCS for 88 d (period 1) and thereafter a mixed red clover-white clover-grass silage for 48 d (period 2). Total dry matter intake and milk yield were not affected by forage type but increased with concentrate supplementation. Intake of isoflavones was several times greater in RCS than in WCS, whereas intake of lignans was
greater in WCS. Concentrate supplementation reduced the intake of most phytoestrogens. Compared with WCS, RCS diets yielded milk with a greater content of flavonoids, whereas milk from WCS diets had greater contents of the mammalian lignans enterodiol and enterolactone. The content of the isoflavan equol was particularly high in RCS diets. There was no apparent carryover effect of clover type on milk phytoestrogen content because there was no difference in content between the silage treatments 3 wk after the cows were transferred to the same silage diet (period 2). Concentrate supplementation reduced the milk contents of the flavonoids equol, biochanin A, and daidzein and increased
the content of mammalian lignans. The effects of silage type and concentrate supplementation on milk contents of the individual phytoestrogens were related to the intake of the compound or its precursor, except for the effect of concentrate on mammalian lignans, for which the intake of the known precursors was also reduced. Overall, this study shows that feeding cows with silage containing red clover increases the milk content of flavonoids at both low and high concentrate supplementation levels, and decreases the content of nonflavonoids such as mammalian lignans, when compared with silage containing white clover. The increased content of phytoestrogens in milk may be important when the health benefits of milk are studied.


EPrint Type:Journal paper
Keywords:clover species, concentrate level, milk phytoestrogen content, equol
Subjects: Food systems > Food security, food quality and human health
Animal husbandry > Production systems > Dairy cattle
Animal husbandry
Animal husbandry > Feeding and growth
Research affiliation: Norway > UMB - Norwegian University of Life Sciences
Denmark > AU - Aarhus University > AU, DJF - Faculty of Agricultural Sciences
Norway > Bioforsk - Norwegian Institute for Agriculture and Environmental Research > Bioforsk Organic Food and Farming Division
Deposited By: Steinshamn, Dr Håvard
ID Code:13810
Deposited On:05 Aug 2008
Last Modified:12 Apr 2010 07:37
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

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