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Fatty acid content, vitamins and selenium in bulk tank milk from organic and conventional Swedish dairy herds during the indoor season

Fall, Nils and Emanuelson, Ulf (2011) Fatty acid content, vitamins and selenium in bulk tank milk from organic and conventional Swedish dairy herds during the indoor season. Journal of dairy research, 78, pp. 287-292.

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Summary

Fatty acids, vitamins and minerals in milk are important for the human consumer, the calf and the cow. Studies indicate that milk from organic and conventional dairy herds may differ in these aspects. The aim of this study was therefore to investigate whether there are differences in the fatty acid composition and concentration of vitamins and selenium in milk between organic and conventional herds in Sweden. Bulk tank milk was sampled in 18 organic and 19 conventional dairy herds on three occasions during the indoor season 2005-2006. Herd characteristics were collected by questionnaires and from the official milk recording scheme. Multivariable linear mixed models were used to evaluate the associations between milk composition and type of herd, while adjusting for potential confounders and the repeated observations within herd. In addition to management type, variables included in the initial models were housing type, milk fat content, herd size, average milk yield and time on pasture during summer. The median concentration of conjugated linoleic fatty acids (CLA) was 0-63% in organic compared with 0.48% in conventional herds, the content of total n-3 fatty acids was 1.44% and 1-04% in organic and conventional milk, respectively, and the content of total n-6 fatty acids was 2.72% and 2.20% in organic and conventional milk, respectively. The multivariable regression models indicated significantly higher concentrations of CLA, total n-3 and n-6 fatty acids in organic milk and a more desirable ratio of n-6 to n-3 fatty acids, for the human consumer, in organic milk. The multivariable models did not demonstrate any differences in retinol, alpha-tocopherol, beta-carotene or selenium concentrations between systems. Median concentrations of alpha-tocopherol were 0.80 mu g/ml in organic and 0.88 mu g/ml in conventional milk, while for beta-carotene the median concentrations were 0-19 and 0.18 mu g/ml, respectively; for retinol, the median concentration was 0.32 mu g/ml in both groups; the median concentrations of selenium were 13.0 and 13.5 mu g/kg, respectively, for organic and conventional systems.


EPrint Type:Journal paper
Subjects: Animal husbandry > Production systems > Dairy cattle
Animal husbandry
Animal husbandry > Health and welfare
Research affiliation: Sweden
Sweden > Swedish University of Agricultural Sciences (SLU)
Sweden > Swedish University of Agricultural Sciences (SLU) > Clinical Sciences
DOI:10.1017/S0022029911000392
Deposited By: Emanuelson, Professor Ulf
ID Code:25067
Deposited On:27 Jan 2014 08:21
Last Modified:27 Jan 2014 08:21
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

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