home    about    browse    search    latest    help 
Login | Create Account

Fatty acid composition, fat-soluble vitamin concentrations and oxidative stability in bovine milk produced on two pastures with different botanical composition

Adler, Steffen A.; Dahl, A.V.; Jensen, S.K.; Thuen, E.; Gustavsson, A.-M. and Steinshamn, H. (2013) Fatty acid composition, fat-soluble vitamin concentrations and oxidative stability in bovine milk produced on two pastures with different botanical composition. Livestock Science, 154, pp. 93-102.

[img] PDF - English
Limited to [Depositor and staff only]

423kB

Summary

Previous research has shown that grazing pastures compared to feeding preserved forages has large impact on milk fatty acid (FA) composition, but differences between grazing red clover (Trifolium pratense L.) or white clover (Trifolium repens L.) are small, whereas the herbage proportions of dicotyledon botanical families is positively correlated with the milk-fat proportions of total polyunsaturated FA when grazing pastures in the Alps. The objective of the present study was to investigate the influence of botanically different pastures on bovine milk composition and milk susceptibility to oxidation. Two groups of 8 multiparous Norwegian Red dairy cows [mean (standard deviation); 599 (45.1) kg body weight, 73 (15.0) d in milk, 29.9 (2.90) kg milk/d at experiment start] grazed either a short-term pasture (SP) or a long-term pasture (LP). Both pastures were organically managed, meaning that no artificial fertilizers or herbicides were applied. The SP was representative for pastures, which are frequently, i.e. at least every third year, renewed by soil tillage and seeding, whereas LP was representative for pastures, which are less frequently renewed. The SP contained mainly meadow fescue (Festuca pratensis Huds.), timothy (Phleum pratense L.) and red clover and LP contained smooth meadow grass (Poa pratensis L.), white clover and a variety of unsown species. Sixteen cows were blocked according to milk yield, days in milk and sire, and randomly within block allocated to the 2 dietary treatments with a daily pasture allowance of 15–20 kg dry matter per cow, supplemented with 3.0 kg barley (Hordeum vulgare L.) concentrate. Milk was sampled during the last week of 3 experimental periods and analysed for FA composition by gas chromatography, concentrations of fat-soluble vitamins by high performance liquid chromatography, and oxidative stability in a light-exposure experiment by measuring the formation of hydroperoxides and by front-face fluorescence spectroscopy. Pasture type had no effect on milk yield, milk gross composition, and only minor effects on milk FA composition. Milk from SP had higher concentration of α-tocopherol than LP. The formation of hydroperoxides in milk was lower for SP than LP after 24 h light exposure, but no differences were found after 48 h. Front-face fluorescence spectroscopy revealed slightly higher formation of components in the area of 409–480 nm wavelength for SP than LP, which may be related to milk-lipid oxidation. The experimental pastures differed mainly in herbage proportions of red clover and white clover and less in proportions of non-legume dicotyledons. This explains small differences in milk FA composition and milk susceptibility to oxidation.


EPrint Type:Journal paper
Keywords:Grazing;Botanical composition; Milk composition;Fatty acid; Fat-soluble vitamin;Oxidative stability
Agrovoc keywords:
LanguageValueURI
EnglishUNSPECIFIEDUNSPECIFIED
Subjects: Animal husbandry > Production systems > Dairy cattle
Crop husbandry > Production systems > Pasture and forage crops
Food systems > Food security, food quality and human health
Research affiliation: European Union > CORE Organic > PHYTOMILK
Denmark > AU - Aarhus University > AU, DJF - Faculty of Agricultural Sciences
Norway > Nofima (formerly Matforsk)
Norway > NMBU - Norwegian University of Life Sciences
Norway > Bioforsk - Norwegian Institute for Agriculture and Environmental Research > Bioforsk Organic Food and Farming Division
Sweden > Swedish University of Agricultural Sciences (SLU) > Agricultural Research for Northern Sweden
ISSN:1871-1413
DOI:10.1016/j.livsci.2013.03.013
Deposited By: Steinshamn, Dr Håvard
ID Code:23128
Deposited On:26 Aug 2013 07:10
Last Modified:26 Aug 2013 07:10
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

Repository Staff Only: item control page