Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 333838
Title Quick changes in milk fat composition of cows after transition from fresh grass to a silage diet
Author(s) Elgersma, A.; Ellen, G.; Horst, H. van der; Boer, H.; Dekker, P.R.; Tamminga, S.
Source Animal Feed Science and Technology 117 (2004)1-2. - ISSN 0377-8401 - p. 13 - 27.
Department(s) Crop and Weed Ecology
Animal Nutrition
Publication type Refereed Article in a scientific journal
Publication year 2004
Keyword(s) conjugated linoleic-acid - lolium-perenne l. - vaccenic acid - bovine-milk - dairy-cows - trans-11 - cultivar - lipids - cis-9
Abstract Two experiments were conducted to evaluate the effects on milk composition of transition from a fresh grass diet on pasture to a winter diet of mixed grass/maize silage. In trial 1, the change in milk fatty acid profile for six dairy cows in mid-lactation was followed via analysis of milk samples collected from individual cows on days 0, 2, 6 and 14 after the transition of diet. In trial 2, milk of 12 cows was analysed on days 0 and 4 after transition. In trial 1, dry matter intake and milk production did not change during the experiment. After transition, the average milk fat content increased from 43.7 g/kg on day 0 to 54.9 g/kg on day 14 and the milk fatty acid composition altered within two days. The largest changes occurred in the proportions of C 14:0 (from 89 g/kg milk fat on day 0 to 117 g/kg on day 14), C 16:0 (226-348 g/kg), C18:0 (110-88 g/kg) and C18:1 cis-9 (238-170 g/kg). The average content of conjugated linoleic acid (CLA) decreased from 24.3 g/kg milk fat on day 0 to 4.4 g/kg on day 14, while the proportion of the beneficial n-7 fatty acid (FA) rumenic acid declined from 0.95 to 0.85 of total CLA. Vaccenic acid contents decreased linearly with CLA contents. Two days after transition large changes had occurred, whereas the changes between day 6 and day 14 were relatively small. These results were confirmed by the results of trial 2, which also indicated that most changes actually took place within four days after transition. The milk fatty acid profile of grazing cows was more favourable from a consumer health perspective than that of silage-fed cows. (C) 2004 Elsevier B.V. All rights reserved.
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