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Factors affecting fatty acid composition in forage and milk

Arvidsson, Katarina (2009). Factors affecting fatty acid composition in forage and milk. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2009:62
ISBN 978-91-576-7409-8
[Doctoral thesis]

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The aims of the studies underlying this thesis were to evaluate variations in fatty acid (FA) contents of plants used as forage for dairy cows in northern Sweden, and their effects on the FA contents of the milk. Initially, samples of timothy (Phleum pratense L.) were subjected to different pre-treatments prior to analysis. Freezing with liquid N was not necessary to obtain apparently reliable FA profiles of the samples examined. The prevailing method for handling samples before analysis, i.e. freeze-drying and grinding, was satisfactory. However, heat drying samples at 60°C was just as good, or even better in some cases. Neither wilting (to 330-350 g dry matter/kg) nor application of additives (acid additive or bacterial inoculant) to timothy had any substantial effects on the proportions of FAs in silage. In addition, seasonal variations in FA concentrations were evaluated in timothy and meadow fescue (Festuca pratensis Huds.) subjected to three different N fertilization regimes and harvested at different stages of maturity during their spring and summer growth periods. FA concentrations in both grasses declined over time in both growth periods. There were positive linear relationships between FAs and concentrations of crude protein (CP) and crude fat, which might be useful as tools to predict FA concentrations in the forage. Furthermore, the two grass species examined showed differences in FA profiles, notably timothy had higher concentrations of C18:2 n-6 and meadow fescue higher concentrations of C18:3 n-3, but the total fatty acid concentrations were similar in both grasses. In addition, three timothy silages subjected to different N-fertilization regimes and a red clover/timothy silage (60:40 on DM basis) were fed to 24 dairy cows in a change-over design. Higher levels of N-fertilization led to higher concentrations of CP accompanied by higher concentrations of FAs in silage. However, these differences did not affect the concentrations of either protein or 18:3n-3 in the milk of cows fed these grass silages, but including red clover in the cows’ diet led to increased concentrations of C18:3 n-3 and cis-9, trans-11 18:2 in their milk.

Authors/Creators:Arvidsson, Katarina
Title:Factors affecting fatty acid composition in forage and milk
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2009
Number of Pages:52
ALLI K. Arvidsson, A-M. Gustavsson and K. Martinsson (2009). Fatty acids in forages: A comparison of different pre-treatments prior to analysis. Animal Feed Science and Technology 151, 143-152. II K. Arvidsson, A-M. Gustavsson and K. Martinsson (2009). Effects of conservation method on fatty acid composition of silage. Animal Feed Science and Technology 148, 241-252. III K. Arvidsson, A-M. Gustavsson and K. Martinsson. Fatty acid concentrations in timothy (Phleum pratese L.) and meadow fescue (Festuca pratensis Huds.): effects of seasonal variations at different nitrogen fertilization levels (manuscript). IV K. Arvidsson, A-M. Gustavsson and K. Martinsson. The effect of crude protein level and fatty acid concentration in silage on the fatty acid composition of dairy cow milk (manuscript).
Place of Publication:Umeå
ISBN for printed version:978-91-576-7409-8
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:phleum pratense, festuca pratensis, trifolium repens, feed crops, fatty acids, cow milk, proximate composition, preharvest treatment, silage, wilting, nitrogen fertilizers, fertilizer application, seasonal variation, sweden
Keywords:Fatty acids, Festuca pratensis Huds., Milk production, Pre-treatments, N-fertilization, Phleum pretense L., Seasonal variation, Silage, Trifolium repens L., Wilting
Permanent URL:
ID Code:2097
Department:(NL, NJ) > Dept. of Agricultural Research for Northern Sweden
(VH) > Dept. of Agricultural Research for Northern Sweden
Deposited By: Katarina Arvidsson
Deposited On:07 Sep 2009 00:00
Metadata Last Modified:02 Dec 2014 10:16

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