Effect of Dietary and Animal Factors on Milk Fatty Acids Composition of Grazing Dairy Cows: A Review

Document Type: Review Articles


Centro de Investigaciones Agrarias de Mabegondo, INGACAL, Apdo 10, 15080, A Coruna, Spain


In pasture-based milk production systems, using available farm resources in order to reduce feeding costs, the composition and functional properties of dairy cows’ milk are of considerable importance to the dairy farmer, manufacturer and consumer. Basically, there are three options for altering the composition and/or functional properties of milk: 1) cow nutrition and grazing management, 2) cow genetics and 3) dairy manufacturing technologies. At the farm levels, manipulation of milk composition only occurs when it is perceived to be more profitable, normally, processing options are the option most considered. Nevertheless, opportunities exist for manipulation of milk composition on the farm to improve the human and physiological properties of milk and dairy products, such as enhanced concentrations of conjugated linoleic acid (CLA), or to improve its milk fatty acids (FA) composition for more efficient processing into a range of dairy products. This review considers the effect of dietary (pasture feeding, lipid feed supplements, seasonal and regional variations) and animal (breed, stage of lactation, parity and animal to animal) factors on milk FA composition of grazing dairy cows. Furthermore, it highlights the relevance that these factors, in the context of an integrative-view, might play on the sustainability of pasture-based milk production systems in humid areas in terms of milk differentiation and higher added value which profit would be directly reached for the milk producer on the farm.


Ashes J.R., Vincent S.T., Welch P., Gulati S.K., Scott T.W., Brown G.H. and Blakeley S. (1992). Manipulation of the fatty acid composition of milk by feeding protected canola seeds. J. Dairy Sci.75, 1090-1096.
Auldist M.J., Walsh B.J. and Thomson N.A. (1998).Seasonal and lactational influences on bovine milk composition in New Zealand. J. Dairy Res.65, 401-411.
Banni S. and Martin J.C. (1998). Conjugated linoleic acid and metabolites. Pp. 261-302 inTrans Fatty Acids in Human Nutrition. J.J. Sébédio and W.W. Christie Eds., Oily Press. Dundee, Scotland.
Bauman D.E. and Griinari J.M., 2001. Regulation and nutritional manipulation of milk fat: low-fat milk syndrome. Livest. Prod. Sci. 70, 15-29.
Bauman D.E., Corl B.A. and Peterson D.G. (2003). The biology of conjugated linoleic acids in ruminants. Pp. 146-173 inAdvances in Conjugated Linoleic Acid Research. J.L. Sébédio W.W. Christie and R. Adlof Ed., AOCS Press. Champaign, USA.
Belury M.A. (1995). Conjugated dienoic linoleate: A polyunsaturated fatty acid with unique chemoprotetive properties. Nutr. Rev. 53, 83-89.
Benjamin S. and Spener F. (2009). Conjugated linoleic acids as functional food: An insight into their health benefits. Nutr. Metab. 6,36.
Booth R.G., Kon S.K., Dann W.J. and Moore T. (1935). A study of seasonal variation in butter fat. II. A seasonal spectroscopic variation in the fatty acid fraction. Biochem. J. 29, 133-137.
Bugaud C., Buchin S., Coulon J.B., Hauwuy A. and Dupont D. (2001). Influence of the nature of alpine pastures on plasmin activity, fatty acid and volatile compound composition of milk. Le Lait. 81(3), 401-414.
Casals R., Caja G., Pol M.V., Such X., Albanell E., Gargouri A. and Casellas J. (2006). Response of lactating dairy ewes to various levels of dietary soaps of fatty acids. Anim. Feed Sci. Technol. 131, 312-332.
Chardigny J.M., Destaillats F., Malpuech-brugère C., Moulin J., Bauman D.E., Lock A.L., Barbano D.M., Mensink R.P., Bezelgues J.B., Chaumont P., Combe N., Cristiani I., Joffre F., German J.B., Dionisi F., Boirie Y. and Sébédio J.L. (2008). Do trans fatty acids from industrially produced sources and from natural sources have the same effect on cardiovascular disease risk factors in healthy subjects? Results of the trans fatty acids collaboration (TRANSFACT) study. Am. J. Clin. Nutr. 87, 558-566.
Chilliard Y., Rouel J., Ferlay A., Bernard L., Gaborit P., Raynal-Ljutovac K., Lauret A. and Leroux C. (2006). Optimising goat’s milk and cheese fatty acid composition. Pp.  281-312 inImproving the Fat Content of Foods. Ed., Wood-Head Publ. Ltd. UK.
Chilliard Y., Glasser F., Ferlay A., Bernard L., Rouel J. and Doreau M. (2007). Diet, rumen biohydrogenation and nutritional quality of cow and goat milk fat. Eur. J. Lipid Sci. Technol. 109, 828-855.
Chouinard P.Y., Corneau L., Bauman D.E., ButlerW.R., Chilliard Y. and Drackley J.K. (1998). Conjugated linoleic acid content of milk from cows fed different sources of dietary fat. J. Dairy Sci. 81, 223.
Chouinard P.Y., Corneau L., ButlerW.P., Drackley J.K. and Bauman D.E. (2001). Effect of dietary lipid source on conjugated linoleic acid concentrations in milk fat. J. Dairy Sci. 84, 680-690.
Christie W.W. (1979). The effect of diet and other factors on the lipid composition of ruminant tissues and milk. Prog. Lipid Res. 17, 245-277.
Christie W.W. (1981). The effects of diet and other factors on the lipid composition of ruminant tissues and milk. Pp. 193-226 inLipid Metabolism in Ruminant Animals. W.W. Christie Ed., Pergamon Press. Oxford, UK.
Clandinin M.T. (2000). The effect of palmitic acid on lipoprotein cholesterol levels. Int. J. Food Sci. Nutr. 51, 61-71.
Collomb M., ButikoferU., Sieber R., Jeangros B. and Bosset J.O. (2002). Composition of fatty acids in cow’s milk fat produced in the lowlands, mountains and highlands of Switzerland using high-resolution gas chromatography. Int. Dairy J. 12, 649-659.
Collomb M., Sollberger H., BütikoferU., Sieber R., Stoll W. and Schaeren W. (2004). Impact of a basal diet of hay and fodder beet supplemented with rapeseed, linseed and sunflower seed on the fatty acid composition of milk fat. Int. Dairy J.14, 549-559.
Craig-Schmidt M.C. (2006). World-wide consumption of trans fatty acids. Atheroscler. Suppl. 7, 1-4.
Curran J., Delaby L., Keneddy E., Murphy J.P., Boland T.M. and O’Donovan M. (2010). Sward characteristics, grass dry matter intake and milk production performance are affected by pre-grazing herbage mass and pasture allowance. Livest. Prod. Sci. 127, 144-154.
DawsonR.M.C. and Kemp P. (1970). Biohydrogenation of dietary fats in ruminants. Pp. 504-518 in A.T. Phillipson. Physiology of Digestion and Metabolism in the Ruminant. Ed., Oriel Press. Newcastle, UK.
DawsonR.M.C., Hemington N., Grime D., Lander D. and Kemp P. (1974). Lipolysis and hydrogenation of galactolipids and the accumulation of phytanic acid in the rumen. Biochem. J. 144, 169-171.
DawsonR.M.C., Hemington N. and Hazlewood G.P. (1977). On the role of higher plant and microbial lipases in the ruminal hydrolysis of grass lipids. Br. J. Nutr. 38, 225-232.
Dewhurst R.J. and King P.J. (1998). Effects of extended wilting, shading and chemical additives on the fatty acids in laboratory grass silages. Grass. Forage. Sci. 53, 219-224.
Dewhurst R.J., Scollan N.D., Lee M.R.F., Ougham H.J. and Humphreys M.O. (2003a). Forage breeding and management to increase the beneficial fatty acid content of ruminant products. Proc. Nutr. Soc. 62, 329-336.
Dewhurst R.J., Fisher W.J., TweedJ.K.S. and Wilkins R.J. (2003b). Comparison of grass and legume silages for milk production. 1. Production responses with different levels of concentrate. J. Dairy Sci. 86, 2598-2611.
Dewhurst R.J., Evans R.T., ScolanN.D., Moorby J.M., Mery R.J. and WilkinsR.J. (2003c). Comparison of grass and legume silages for milk production. 2. Invivo and in saccoevaluations of rumen function. J. Dairy Sci.86, 2612-2621.
Dewhurst R.J., Shingfield K.J., Lee M.R.F. and ScollanN.D.(2006). Increasing the concentrations of beneficial polyunsaturated fatty acids in milk produced by dairy cows in high-forage systems. Anim. Feed Sci. Technol. 131, 168-206.
Dhiman T.R., Helmink E.D., McMahon D.J., FifeR.L. and Pariza M.W. (1999a). Conjugated linoleic acid content of milk and cheese from cows fed extruded oilseeds. J. Dairy Sci.82,412-419.
Dhiman T.R., Anand G.R., Satter L.D. and Pariza M.W. (1999b). Conjugated linoleic acid content of milk from cows fed different diets. J. Dairy Sci. 82, 2146-2156.
Dhiman T.R., Satter L.D., Pariza M.W., Galli M.P., Albright K. and Tolosa M.X. (2000). Conjugated linoleic acid (CLA) content of milk from cows offered diets rich in linoleic and linolenic acid. J. Dairy Sci. 83, 1016-1027.
Doreau M. and Poncet C. (2000). Ruminal biohydrogenation of fatty acids originating from fresh or preserved grass. Repr. Nutr. Dev. 40, 201.
Dunshea F.R., BellA.W. and Trigg T.E. (1989). Relations between plasma non-esterified fatty acid metabolism and body fat mobilization in primiparous lactating goats. Br. J. Nutr.62,5 1-61.
Dunshea F.R., BellA.W. and Trigg T.E. (1990). Body composition changes in goats during early lactation estimated using a two-pool model of tritiated water kinetics. Br. J. Nutr.64,121-131.
EFSA. (2004). Opinionof the scientific panel on dietetic products, nutrition and allergies (NDA) related to the presence of trans fatty acids in foods and the effect on human health of the consumption of trans fatty acids. EFSA J.81, 1-49.
Elgersma A., Ellen G., Dekker P.R., Van der Horst H., Boer H. and Tamminga S. (2003a). Effects of perennial ryegrass (Lolium perenne) cultivars with different linolenic acid contents on milk fatty acid composition. Asp. Appl. Biol.70, 107-114.
Elgersma A., Ellen G., Van der Horst H., Muuse B.G., Boer H. and Tamminga S. (2003b). Influence of cultivar and cutting date on the fatty acid composition of perennial ryegrass. Grass. Forage. Sci. 58, 323-331.
Elgersma A., Tamminga S. and Ellen G. (2003c). Comparison of the effects of grazing and zero-grazing of grass on milk fatty acid composition of dairy cows. Grassl. Sci. Eur. 8,271-274.
Elgersma A., Ellen G., Van Der Horst H., Muuse B.G., Boer H. and Tamminga S. (2004a). Quick changes in milk fat composition after transition from fresh grass to a silage diet and effects on consumer health benefits. Anim. Feed Sci. Tech. 117, 13-27.
Elgersma A., Ellen G. and Tamminga S. (2004b). Rapid decline of contents of beneficial omega-7 fatty acids in milk from grazing cows with decreasing herbage allowance. Grassl. Sci. Eur. 9, 1136-1138.
Elgersma A., Tamminga S. and Ellen G. (2006). Modifying milk composition through forage. Anim. Feed Sci. Technol. 131, 207-225.
Ellen G. and Elgersma A. (2004). Letter to the editor: Plea for using the term n-7 fatty acids in place of C18:2 cis-9, trans-11 and C18:1 trans-11 or their trivial names rumenic acid and vaccenic acid rather than the generic term conjugated linoleic acids. J. Dairy Sci. 87, 1131.
Elwood P.C., Givens D.I., Beswick A.D., Fehily A.M., PickeringJ.E. and Gallacher J. (2008). The survival advantage of milk and dairy consumption: An overview of evidence from cohort studies of vascular diseases, diabetes and cancer. J. Amer. Coll. Nutr. 27, 723-734.
Fellner V., Sauer F.D. and Kramer J.K.G. (1997). Effect of nigericin, monensin, and tetronasin on biohydrogenation in continuous flow-through ruminal fermenters. J. Dairy Sci. 80, 921-928.
Ferlay A., Agabriel C., Sibra C., Journal C., Martin B. and Chilliard Y. (2008). Tanker milk variability in fatty acids according to farm feeding and husbandry practices in a French semi-mountain area. Dairy Sci. Technol. 88, 193-215.
Fernández M.L. and Webb D. (2008). Review: the LDL to HDL cholesterol ratio as a valuable tool to evaluate coronary heart disease risk. J. Am. Coll. Nutr. 27, 1-5.
Gargouri A., Caja G., Casals R. and MezghaniI.(2006). Lactational evaluation of effects of calcium soap of fatty acids on Dairy ewes. Small Rumin. Res. 66, 1-10.
Gómez-Cortés P., Frutos P., Mantecón A.R., Juárez M., De la Fuente M.A. and Hervás G. (2008). Milk production, Conjugated Linoleic acid content, and in vitro ruminal fermentation in response to High levels of soybean oil in Dairy ewe diet. J. Dairy Sci. 91, 1560-1569.
González-Rodríguez A., Roca-Fernández A.I., Vázquez-Yáñez O.P. and Fernández-Casado J.A. (2009). Contenido de ácido linoleico conjugado (CLA) en leche de vacuno en sistemas de producción en pastoreo en zonas húmedas. Pp. 519-526 in Proc. Libro de Actas de la XLVIII Reunión Científica de la SEEP. Huesca, España.
Griinari J.M. and Bauman D.E. (1999). Biosynthesis of conjugated linoleic acid and its incorporation into meat and milk in ruminants. Pp. 180-200 inAdvances in Conjugated Linoleic Acid Research. Vol. I. M.P. Yurawecz, M.M. Mossoba, J.K.G. Kramer, M.W. Pariza and G.J. Nelson Eds., AOCS Press, Champaign, USA.
GriinariJ.M., Dwyer D.A., McGuire M.A., Bauman D.E., Palmquist D.L. and Nurmela K.V.V. (1998). Trans octadecenoic acids and milk fat depression in lactating dairy cows. J. Dairy Sci. 81, 1251-1261.
Griinari J.M., Nurmela K., Dwyer D.A., Barbano D.M. and Bauman D.E. (1999). Variation of milk fat concentration of conjugated linoleic acid andmilk fat percentage is associated with a change in ruminalbiohydrogenation. J. Anim. Sci. 77, 117-118.
Griinari J.M., Corl B.A., Lacy S.H., Chouinard P.Y., Nurmela K.V.V. and Bauman D.E. (2000). Conjugated linoleic acid is synthesized endogenously in lactating dairy cows by ∆9-desaturase. J. Nutr. 130, 2285-2291.
Grummer R.R. (1991). Effect of feed on the composition of milk fat. J. Dairy Sci. 74, 3244-3257.
Gutiérrez-Toral P. (2010). Supplementation of the diet of dairy ewes with sunflower oil and marine lipids to modulate milk fat composition. Ph D Thesis. Instituto de Ganadería de Montaña del Consejo Superiorde Investigaciones Científicas and Universidad de León. León, España.
Harfoot C.G. and Hazlewood G.P. (1988). Lipid metabolism in the rumen. Pp. 285-322 inThe Rumen Microbial Ecosystem. P.N. Hobson Ed., Elsevier. London, UK.
Houseknecht K., Vanden I., Heuvel J.P., Moya-Camarena S.Y., Portocarrerro C.P., Peck L.W., Nickel K.P. and Belury M.A. (1998). Conjugated linoleic acid normalizes impaired glucose tolerance in the Zucker diabetic fatty fa/fa rat. Biochem. Biophys. Res. Commun. 244, 678-682.
Ip C., SinghM., Thompson H.J. and Scimeca J.A. (1994). Conjugated linoleic acid suppresses mammary carcinogenesis and proliferative activity of the mammary gland in the rat. Cancer Res. 54, 1212-1215.
Jahreis G., Fritsche J. and Steinhart H. (1996). Monthly variations of milk composition with special regard to fatty acids depending on season and farm management systems – Conventional versus ecological. Fett. Lipid. 98, 356-359.
Jahries G., Fritsche J. and Steinhart H. (1997). Conjugated linoleic acid in milk fat: High variation depending on production system. Nutr. Res. 17, 1479-1484.
Jensen R.G. (2002). The composition of bovine milk lipids: January 1995 to December 2000. J. Dairy Sci. 85, 295-350.
Jiang J., Bjorck L., Fonden R. and Emanuelson M. (1996). Occurrence of conjugated cis-9, trans-11 octadecadienoic acid in bovine milk: effects of feed and dietary regimen. J. Dairy Sci. 79, 438-445.
Kay J.K., Mackle T.R., Auldist M.J., Thompson N.A. and Baum-an D.E. (2004). Endogenous synthesis of cis-9, trans-11 conjugated linoleic acid in dairy cows fed fresh pasture. J. Dairy Sci. 87, 369-378.
Keeny M. (1970). Lipid metabolism in the rumen. Pp. 489-503 inPhysiology of Digestion and Metabolism in the Ruminant. A.T. Phillipson Ed., Oriel Press. Newcastle, UK.
Kelly M.L., BerryJ.R., Dwyer D.A., Griinari J.M., Chouinard P.Y., Van Amburgh M.E. and Bauman D.E. (1998a). Dietary fatty acid sources affect conjugated linoleic acid concentrations in milk from lactating dairy cows. J. Nutr. 128, 881-885.
Kelly M.L., Kolver E.S., Bauman D.E., Van Amburgh M.E. and Muller L.D. (1998b). Effect of intake of pasture on concentrations of conjugated linoleic acid in milk of lactating cows. J. Dairy Sci. 81, 1630-1636.
Kelsey J.A., Corl B.A. and Bauman D.E. (2003). The effect of breed, parity, and stage of lactation on conjugated linoleic acid (CLA) in milk fat from dairy cows. J. Dairy Sci. 86, 2588-2597.
Kemp P. and Lander D.J. (1984). Hydrogenation in vitro of α-linolenic acid to stearic acid by mixed cultures of pure strains of rumen bacteria. J. Gen. Microbiol. 130, 527-533.
Kepler C.R., Tucker W.P. and Tove S.B. (1966). Intermediates and products of the biohydrogenation of linoleic acid by Butyrivibrio fibrisolvens. J. Biol. Chem. 241, 1350-1354.
Khanal R.C. (2004). Dietary influence on conjugated linoleic acid content of milk and consumer acceptability of milk and cheese naturally enriched with conjugated linoleic acid. Ph D Thesis. UtahState University. Logan, Utah, USA.
Khanal R.C. and Olson K.C. (2004). Factors affecting conjugated linoleic acid (CLA) content in milk, meat, and egg: A Review. PakistanJ. Nutr.3(2),82-98.
Kraft J., Collomb M., Möckel P., Sieber R. and Jahreis G. (2003). Differences in CLA isomer distribution of cow’s milk lipids. Lipids. 38, 657-664.
Kuzdal-Savoie S. and Kuzdal W. (1961). Influence de la mise à l’herbe des vaches laitières sur les indices de la matière grassedu beurre et sur les teneurs en différents acides gras polyinsaturés. Effect of extruded full-fat soybeans on conjugated. Anim. Bioch. Biophys. 1, 47-69.
Kühlsen N., Pfeuffer M., Soustre Y., MacGibbon A., Lindmark-Mansson H. and Schrezenmeir J. (2005). Trans fatty acids: scientific progress and labelling. Bull. Int. Dairy Fed. 393, 1-19.
Lal D. and Narayanan K.M. (1984). Effect of lactation number on the poly-unsaturated fatty acids and the oxidative stability of milk fats. Ind.J. Dairy Sci.37, 225-229.
LavillonièreF., Martin J.C., Bougnoux P. and Sébédio J.L. (1998). Analysis of conjugated linoleic acid isomers and content in French cheeses. J. Am. Oil Chem. Soc. 75, 343-352.
Lawless F., Murphy J.J., Harrington D., Devery R. and StantonC. (1998). Elevation of cis-9, trans-11-octadecadienoic acid in bovine milk because of dietary supplementation. J. Dairy Sci. 81, 3259-3267.
Lawless F., StantonC., Escop P.L., Devery R., Dillon P. and Murphy J.J. (1999). Influence of breed on bovine milk cis-9, trans-11-conjugated linoleic acid content. Livest. Prod. Sci. 62, 43-49.
Leat W.M.F., Kemp P., Lysons R.J. and Alexander T.J.L. (1977). Fatty acid composition of depot fats from gnotobiotic lambs. J. Agric. Sci. 88, 175-179.
Lee M.R.F., Winters A.L., Scollan N.D., Dewhurst R.J., Theodo-rou M.K. and Minchen F.R. (2003). Plant-mediated lypolysis and proteolysis in red clover with different polyphenol exidase activities. J. Sci. Food Agric. 84, 1639-1645.
Leiber F., Scheeder M.R.L., Wettstein H.R. and Kreuzer M. (2004). Milk fatty acid profile of cows under the influence of alpine hypoxia and high mountainous forage quality. J. Anim. Feed Sci. 13(Suppl.1), 693-696.
Leiber F., Kreuzer M., Nigg D., Wettstein H.R. and Scheeder M.R. (2005). A study on the causes for the elevated n-3 fatty acids in cows’ milk of alpine origin. Lipids. 40, 191-202.
Lock A.L., Corl B.A., Barbano D.M., Bauman D.E. and Ip C. (2004). The anticarcinogenic effect of trans-11 18:1 is dependent on its conversion to cis-9, trans-11 CLA by D9-desaturase in rats. J.Nutr. 134, 2698-2704.
Loor J.J., Herbein J.H. and Jenkins T.C. (2002a). Nutrient digestion, biohydrogenation, and fatty acid profiles in blood plasma and milk fat from lactating Holsteincows fed canola oil or canolamide. Anim. Feed Sci. Tec. 97, 65-82.
Loor J.J., Herbein J.H. and Polan C.E. (2002b). Trans18:1 and 18:2 isomers in blood plasma and milk fat of grazing cows fed a grain supplement containing solvent-extracted or mechanically extracted soybean meal. J. Dairy Sci. 85, 1197-1207.
Mattsson S. (1949). Poly-unsaturated fatty acids in butter and their influence on the oxidation of butter. Methods of analysis and preliminary results. Pp. 308-324 inProc. XIIth Int. Dairy Congress. Section II. Stockholm, Sweden.
Mensink R.P., Zock P.L., Kester A.D.M. and Katan M.B. (2003). Effects of dietary fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on serum lipids and apolipoproteins: A meta-analysis of 60 controlled trials. Am. J. Clin. Nutr. 77, 1146-1155.
Mouriot J., Bernard L., Capitan P., Joly C., Loreau O., Chardigny J.M. and Chilliard Y. (2009). Quantitative estimation of the endogenous synthesis of rumenic acid in goats fed lipid supplements. Pp. 448-449 inProc. XIth Int. Symposium on Ruminant Physiology. Ruminant Physiology, Digestion, Metabolism, and Effects of Nutrition on Reproduction and Welfare. Wageningen Academic Publishers. Clermont-Ferrand, France.
Mozaffarian D., Katan M.B., Ascherio A., Stampfer M.J. and Willet W.C. (2006). Medical progress-Trans fatty acids and cardiovascular disease. N. Engl. J. Med. 354, 1601-1613.
Noakes M., Nestel P.J. and CliftonP.M. (1996). Modifying the fatty acid profile of dairy products through feedlot technology lowers plasma cholesterol of humans consuming the products. Am. J. Clin. Nutr. 63, 42-44.
Palmquist D.L. and Jenkins T. (1980). Fat in lactations rations: Review. J. Dairy Sci. 63, 1-14.
Palmquist D.L., Beaulieu A.D. and Barbano D.M. (1993). Feed and animal factors influencing milk fat composition. J. Dairy Sci. 76, 1753-1771.
Palmquist D.L., Lock A.L., Shingfield K.J. and Bauman D.E. (2005). Biosynthesis of conjugated linoleic acid in ruminants and humans. Pp. 179-217 in Advances in Food and Nutrition Research. Vol. 50. S.L. Taylor Ed., Elsevier Inc., San Diego, USA.
Palmquist D.L.and Griinari J.M. (2006). Milk fatty acid composition in response to reciprocal combinations of sunflower and fish oils in the diet. Anim. Feed Sci. Technol. 131, 358-369.
Palmquist D.L. (2010). Great discoveries of milk for a healthy diet and a healthy life. R. Bras. Zootec. 39, 465-477.
ParizaM.W., Park Y. and CookM.E.(2001). The biologically active isomers of conjugated linoleic acid. Progr. Lipid. Res. 40, 283-298.
Park Y.W., Juarez M., Ramos M. and Haenlein G.F.W. (2007). Physico-chemical characteristicsof goat and sheep milk. Small Rumin. Res.68, 88-113.
Parodi P.W. (2006). Nutritional significance of milk lipids. Pp. 601-639. Advanced Dairy Chemistry. Volume 2. 3rdEd., P.F. Fox and P.L.H. McSweeney Eds., Springer. New York, USA.
Parodi P.W. (2009). Review: has the association between saturated fatty acids, serum cholesterol and coronary heart disease been over emphasized? Int. Dairy J. 19, 345-361.
Riel R.R. (1963). Physico-chemical characteristics of Canadian milk fat. Unsaturated fatty acids. J. Dairy Sci. 46, 102-106.
Roca-Fernández A.I., González-Rodríguez A., Vázquez-Yáñez O.P. and Fernández-Casado J.A. (2011a). Effects of concentrate source (cottonseed vs. barley) on milk performance and fatty acids profile of Holstein-Friesian dairy cows. Iranian J. Appl. Anim. Sci. 1(4), 245-252.
Roca-Fernández A.I., O’Donovan M., Curran J. and González-Rodríguez A. (2011b). Effect of pre-grazing herbage mass and daily herbage allowance on perennial ryegrass swards structure, pasture dry matter intake and milk performance of Holstein-Friesian dairy cows. Span. J. Agric. Res. 9(1), 86-99.
Roca-Fernández A.I., González-Rodríguez A., and Vázquez-Yáñez O.P. (2012a). Effect of pasture allowance and cows’ lactation stage on perennial ryegrass swards quality, pasture dry matter intake and milk performance of Holstein-Friesian cows. Span. J. Agric. Res. 10(1),116-122.
Roca-Fernández A.I., González-Rodríguez A., Vázquez-Yáñez O.P. and Fernández-Casado J.A. (2012b). Effect of forage source (grazing vs. silage) on conjugated linoleic acid content in milk fat of Holstein-Friesian dairy cows from Galicia(NW Spain). Span. J. Agric. Res. in press.
Rowney M. and Christian M. (1996). Effect of cow diet and stage of lactation on the composition of milk fat for cheese manufacture. Aust. J. Dairy Tech. 51, 118-122.
Roy A., Ferlay A., Shingfield K.J. and Chilliard Y. (2006). Examination of the persistency of milk fatty acid composition responses to plant oils in cows given different basal diets, with particular emphasis on trans-C18:1 fatty acids and isomers of conjugated linoleic acid. Anim. Sci. 82, 479-492.
Roy A., Chardigny J.M., Bauchart D., Ferlay A., Lorenz S., Durand D., Gruffat D., Faulconnier Y., Sébédio J.L. and Chilliard Y. (2007). Butters rich either in trans-10 C18:1 or in trans-11 C18:1 plus cis-9, trans-11 CLA differentially affect plasma lipids and aortic fatty streak in experimental atherosclerosis in rabbits. Anim. Sci. 1, 467-476.
Sánz-Sampelayo M.R., Chilliard Y., Schmidely P. and Boza J. (2007). Influence of type of diet on the fat constituents of goat and sheep milk. Small Rumin. Res. 68, 42-63.
Schroeder G.F., Delahoy J.E., Vidaurreta I., Bargo F., Gagliostro G.A. and Muller L.D. (2003). Milk fatty acid composition of cows fed a total mixed ration or pasture plus concentrates replacing with fat. J. Dairy Sci. 86, 3237-3248.
Scollan N.D., Dewhurst R.J., Moloney A.P. and Murphy J.J. (2005). Improving the quality of products from grassland. Pp. 41-56.inGrassland: A Global Resource. D.A. McGilloway Ed., Wageningen Academic Publishers. Wageningen, Netherlands.
ShaffiB., Mahler K.A., Price W.J. and Auld D.L. (1992). Genotype x environment interaction effects on winter rapeseed yield and oil content.Crop Sci. 32, 922-927.
Shingfield K.J., Chilliard Y., Toivonen V., Kairenius P. and Givens D.I. (2008). Trans fatty acids and bioactive lipids in ruminant milk. Adv. Exp. Med. Biol. 606, 3-65.
Simopoulos A.P. (2002). The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomed. Pharmacother. 56, 365-379.
Singh S. and Hawke J.C. (1979). The in vitro lipolysis and biohydrogenation of monogalactosyldiglycerides by whole rumen contents and its fractions. J. Sci. Food Agric. 30, 603-612.
Siri-Torino P.W., Sun Q., Hu F.B. and Krauss R.M. (2010). Saturated fat, carbohydrate, and cardiovascular disease. Am. J. Clin. Nutr. 91, 535-546.
Smith B.K., Robinson L.E., NamR. and Ma D.W.L. (2009).Trans-fatty acids and cancer: a mini-review. Br. J. Nutr. 102, 1254-1266.
SoyeurtH., Gillon A., Croquet C., Vanderick S., Mayeres P., Bertozzi C. and Gengler N. (2007). Estimation of heritability and genetic correlations for the major fatty acids in bovine milk. J. Dairy Sci. 90, 4435-4442.
Stadhouders J. and Mulder H. (1955). The composition of Dutch butterfat. 1. Seasonal variations in the unsaturatedfatty acid composition of butter fat. Neth. Milk Dairy J. 9, 182-193.
StantonC., Lawless F., Kjellmer G., Harrington D., Devery R., Connolly J.F. and Murphy J. (1997). Dietary influences on bovine milk cis-9, trans-11-conjugated linoleic acid content. J. Food Sci. 62, 1083-1086.
Stockdale C.R., Walker G.P., WalesW.J., Dalley D.E., Birkett A., Shen Z. and Doyle P.T. (2003). Influence of pasture and concentrates in the diet of grazing dairy cows on the fatty acid composition of milk. J. Dairy Res.70, 267-276.
Stoop V.M., Van Arendonk J.A.M., Heck J.M.L., Van Valenberg H.J.F. and Bovenhuis H. (2008). Genetic parameters for major milk fatty acids and milk production traits of Dutch Holstein-Friesians. J. Dairy Sci. 91, 385-394.
Tanaka K. and Shigeno K. (1976). The biohydrogenation of linoleic acid by rumen micro-organisms. Jpn. J. Zootech. Sci. 47, 50-53.
Timmen H. and Patton S. (1988). Milk fat globules: Fatty acid composition,size and in vivo regulation of fat liquidity. Lipids23, 685-689.
Turpeinen A.M., Mutanen M., Aro A., Salminen I., Basu S., Palmquist D.L. and Griinari J.M. (2002). Bioconversion of vaccenic acid to conjugated linoleic acid in humans. Am. J. Clin.Nutr. 76, 504-510.
Tyburczy C., Major C., Lock A.L., Destaillats F., LawrenceP., Brenna J.T., Salter A.M. and Bauman D.E. (2009). Individual trans octadecenoic acids and partially hydrogenated vegetable oil differentially affect hepatic lipid and lipoprotein metabolism in golden syrian hamsters. J. Nutr. 139,257-263.
Van Dorland H.A. (2006). Effect of white clover and red clover addition to ryegrass on nitrogen use efficiency, performance, milk quality and eating behaviour in lactating dairy cows. Ph D Thesis.Swiss Federal Institute of Technology. Zürich, Switzerland.
Van Soest P.J. (1994). Nutritional Ecology of the Ruminant. Second Edn. CornellUniversityPress. Ithaca, New York, USA.
Van Wijlen R.P.J. and Colombani P.C. (2010). Review: grass-based ruminant production methods and human bioconversion of vaccenic acid with estimations of maximal dietary intake of conjugated linoleic acids. Int. Dairy J. 20, 433-448.
Ward A.T., WittenbergK.M., Froebe H.M., Przybylski R. and Malcolmson L. (2003). Fresh forage and solin supplementation on conjugated linoleic acid levels in plasma and milk. J. Dairy Sci. 86, 1742-1750.
White S.L., Bertrand J.A., Wade M.R., Washburn S.P., Green J.R. and Jenkins T.C. (2001). Comparison of fatty acid content of milk from Jersey and Holsteincows consuming pasture or a total mixed ration. J. Dairy Sci. 84, 2295-2301.
Whitlock L.A., Schingoethe D.J., Hippen A.R., Kalscheur K.F. and Abughazaleh A.A. (2003). Milk production and composition from cows fed high oil or conventional corn at two forage concentrations. J. Dairy Sci. 86, 2428-2437.
Williams C.M. (2000). Dietary fatty acids and human health. Ann. Zootech. 49, 165-180.
ŻegarskaZ., Jaworski J., Paszczyk B., Charkiewicz J. and Borejszo Z. (2001). Fatty acid composition with emphasis on trans C18:1 isomers of milk fat from lowland and Black and White and Polish Red Cows. Pol. J. Food Nutr. Sci. 10(51), 41-44.