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A comparison between feeding systems (pasture and TMR) and the effect of vitamin E supplementation on plasma and milk fatty acid profiles in dairy cows.
J Dairy Res. 2005 Aug; 72(3):322-32.JD

Abstract

Unidentified constituents in fresh pasture increase milk fat cis-9, trans-11 conjugated linoleic acid (CLA) concentration, and prevent milk fat depression, even though ruminal conditions conducive to reducing milk fat synthesis exist. One possible explanation is vitamin E (kappa-tocopherol), a constituent high in fresh pasture, but naturally low in conserved/dried forages and cereal grains. Twenty late-lactating dairy cows previously consuming a total mixed ration (TMR) were randomly allocated to one of two dietary treatments for 21 d: TMR (control; n=10); and TMR plus an additional 10,000 i.u. alpha-tocopherol/d (VIT E; n = 10). These cows were simultaneously compared with 13 late-lactation dairy cows previously grazing fresh pasture (PAS) balanced for age, parity and genetic merit. Average daily alpha-tocopherol intakes were approximately 468, 10,520 and 1,590 i.u./cow for the control, VIT E and PAS treatments, respectively. Dietary alpha-tocopherol supplementation (VIT E v. control) slightly increased milk fat content by 0.23 percentage units, but did not significantly alter milk fatty acid composition. Plasma trans-11 18:1 (VA) content tended to increase and trans-10 18:1 levels numerically declined following alpha-tocopherol supplementation suggesting possible changes in rumen biohydrogenation products. In addition, increased alpha-tocopherol intake in TMR-fed cows decreased serum urea levels and tended to alter milk fat 15:0 suggesting changes in rumen microbial populations. However, when compared with cows grazing pasture, TMR-fed cows supplemented with alpha-tocopherol, still produced milk with lower cis-9, trans-11 CLA and VA, and higher trans-10 18:1 concentrations suggesting alpha-tocopherol is not a primary reason for milk fatty acid profile differences between pasture and TMR-fed cows. Therefore, additional unknown pasture constituents favour production of fatty acids originating from the cis-9, trans-11 instead of the trans-10, cis-12 CLA biohydrogenation pathways.

Authors+Show Affiliations

Dexcel Ltd., Private Bag 3221, Hamilton, New Zealand.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

16174364

Citation

Kay, Jane K., et al. "A Comparison Between Feeding Systems (pasture and TMR) and the Effect of Vitamin E Supplementation On Plasma and Milk Fatty Acid Profiles in Dairy Cows." The Journal of Dairy Research, vol. 72, no. 3, 2005, pp. 322-32.
Kay JK, Roche JR, Kolver ES, et al. A comparison between feeding systems (pasture and TMR) and the effect of vitamin E supplementation on plasma and milk fatty acid profiles in dairy cows. J Dairy Res. 2005;72(3):322-32.
Kay, J. K., Roche, J. R., Kolver, E. S., Thomson, N. A., & Baumgard, L. H. (2005). A comparison between feeding systems (pasture and TMR) and the effect of vitamin E supplementation on plasma and milk fatty acid profiles in dairy cows. The Journal of Dairy Research, 72(3), 322-32.
Kay JK, et al. A Comparison Between Feeding Systems (pasture and TMR) and the Effect of Vitamin E Supplementation On Plasma and Milk Fatty Acid Profiles in Dairy Cows. J Dairy Res. 2005;72(3):322-32. PubMed PMID: 16174364.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A comparison between feeding systems (pasture and TMR) and the effect of vitamin E supplementation on plasma and milk fatty acid profiles in dairy cows. AU - Kay,Jane K, AU - Roche,John R, AU - Kolver,Eric S, AU - Thomson,Norman A, AU - Baumgard,Lance H, PY - 2004/09/03/received PY - 2004/11/25/accepted PY - 2005/9/22/pubmed PY - 2005/12/13/medline PY - 2005/9/22/entrez SP - 322 EP - 32 JF - The Journal of dairy research JO - J Dairy Res VL - 72 IS - 3 N2 - Unidentified constituents in fresh pasture increase milk fat cis-9, trans-11 conjugated linoleic acid (CLA) concentration, and prevent milk fat depression, even though ruminal conditions conducive to reducing milk fat synthesis exist. One possible explanation is vitamin E (kappa-tocopherol), a constituent high in fresh pasture, but naturally low in conserved/dried forages and cereal grains. Twenty late-lactating dairy cows previously consuming a total mixed ration (TMR) were randomly allocated to one of two dietary treatments for 21 d: TMR (control; n=10); and TMR plus an additional 10,000 i.u. alpha-tocopherol/d (VIT E; n = 10). These cows were simultaneously compared with 13 late-lactation dairy cows previously grazing fresh pasture (PAS) balanced for age, parity and genetic merit. Average daily alpha-tocopherol intakes were approximately 468, 10,520 and 1,590 i.u./cow for the control, VIT E and PAS treatments, respectively. Dietary alpha-tocopherol supplementation (VIT E v. control) slightly increased milk fat content by 0.23 percentage units, but did not significantly alter milk fatty acid composition. Plasma trans-11 18:1 (VA) content tended to increase and trans-10 18:1 levels numerically declined following alpha-tocopherol supplementation suggesting possible changes in rumen biohydrogenation products. In addition, increased alpha-tocopherol intake in TMR-fed cows decreased serum urea levels and tended to alter milk fat 15:0 suggesting changes in rumen microbial populations. However, when compared with cows grazing pasture, TMR-fed cows supplemented with alpha-tocopherol, still produced milk with lower cis-9, trans-11 CLA and VA, and higher trans-10 18:1 concentrations suggesting alpha-tocopherol is not a primary reason for milk fatty acid profile differences between pasture and TMR-fed cows. Therefore, additional unknown pasture constituents favour production of fatty acids originating from the cis-9, trans-11 instead of the trans-10, cis-12 CLA biohydrogenation pathways. SN - 0022-0299 UR - https://www.unboundmedicine.com/medline/citation/16174364/A_comparison_between_feeding_systems__pasture_and_TMR__and_the_effect_of_vitamin_E_supplementation_on_plasma_and_milk_fatty_acid_profiles_in_dairy_cows_ L2 - https://www.cambridge.org/core/product/identifier/S0022029905000944/type/journal_article DB - PRIME DP - Unbound Medicine ER -