Seasonal profiles of cis-9, trans-11 and trans-10, cis-12 conjugated linoleic acid (CLA) in milk from dairy herds on pasture - An observational study

Publication Type: Contribution to conference
Authors: Tröscher AHA, Tröscher FB, Steinberger S, Kienberger H, Jilg T and Steingaß H.
Year of publication: 2014
Published in: Animal Production in Australia
Band/Volume: 30/
Series/labeling: Proceedings of the 30th Biennial Conference of the Australian Society of Animal Production
ISBN / ISSN / eISSN: 0728-5965
Page (from - to): 24-27
Conference name: Harnessing the Ecology and Physiology of Herbivores
Conference location: Canberra (Australia)
Conference date: 8.-12. September 2014
Keywords: CLA, Linolsäure, Milch, Milchkühe

Abstract

<span style="line-height: 107%; font-family: 'Arial',sans-serif; font-size: 12pt; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-ansi-language: DE; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;">CLAs are discussed for their positive effects on the wellbeing of humans as well as dairy cows. Seasonal milk profiles from cows grazing short sward, for both of the best known CLA isomers cis-9, trans-11 and trans-10, cis-12 are not available. One reason is that the trans-10, cis-12 isomer is difficult to detect. From April to November, we collected in a weekly to bi-weekly routine 186 milk samples from 7 pasture farms. Diets were not supplemented during the pasture season except for one farm which provided 1.5 kg/day ground barley in the parlor and one supplied 1.5 kg/day hay. After verifying the analytical method by spiking milk samples with CLA-triglycerides in the relevant low levels, the samples were analyzed for their fatty acid composition in a GC with FID and a 100 ml column. The seasonal average of the cis-9, trans-11 isomer ranged from 1.42 to 2.92 % in milk fat between the farms; the lowest single farm sample had 0.83 % in mid-April and the highest had 4.14 % in September. The linear model showed highly significant differences for farm, time and farm x time interaction (P < 0.001). For the trans-10, cis-12 isomer annual averages ranged from 0.002 to 0.007 % between farms with a highest level (a single mid-May sample) of 0.016 %. Due to the literature reports on positive effects of trans-10, cis-12 supplementations for the dairy cow, the finding of this isomer in milk from pasture-only farms in early spring should encourage further research.

Involved persons

Dr. Herbert Steingaß

Involved institutions

Animal Nutrition