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Invited review: Organic and conventionally produced milk—An evaluation of factors influencing milk composition

Open ArchivePublished:December 11, 2014DOI:https://doi.org/10.3168/jds.2014-8389

      Abstract

      Consumer perception of organic cow milk is associated with the assumption that organic milk differs from conventionally produced milk. The value associated with this difference justifies the premium retail price for organic milk. It includes the perceptions that organic dairy farming is kinder to the environment, animals, and people; that organic milk products are produced without the use of antibiotics, added hormones, synthetic chemicals, and genetic modification; and that they may have potential benefits for human health. Controlled studies investigating whether differences exist between organic and conventionally produced milk have so far been largely equivocal due principally to the complexity of the research question and the number of factors that can influence milk composition. A main complication is that farming practices and their effects differ depending on country, region, year, and season between and within organic and conventional systems. Factors influencing milk composition (e.g., diet, breed, and stage of lactation) have been studied individually, whereas interactions between multiple factors have been largely ignored. Studies that fail to consider that factors other than the farming system (organic vs. conventional) could have caused or contributed to the reported differences in milk composition make it impossible to determine whether a system-related difference exists between organic and conventional milk. Milk fatty acid composition has been a central research area when comparing organic and conventional milk largely because the milk fatty acid profile responds rapidly and is very sensitive to changes in diet. Consequently, the effect of farming practices (high input vs. low input) rather than farming system (organic vs. conventional) determines milk fatty acid profile, and similar results are seen between low-input organic and low-input conventional milks. This confounds our ability to develop an analytical method to distinguish organic from conventionally produced milk and provide product verification. Lack of research on interactions between several influential factors and differences in trial complexity and consistency between studies (e.g., sampling period, sample size, reporting of experimental conditions) complicate data interpretation and prevent us from making unequivocal conclusions. The first part of this review provides a detailed summary of individual factors known to influence milk composition. The second part presents an overview of studies that have compared organic and conventional milk and discusses their findings within the framework of the various factors presented in part one.

      Key words

      Introduction

      Composition of bovine milk is influenced by many factors related either to the individual animal or to the animal’s environment. Elements such as diet (
      • Ferlay A.
      • Agabriel C.
      • Sibra C.
      • Journal C.
      • Martin B.
      • Chilliard Y.
      Tanker milk variability in fatty acids according to farm feeding and husbandry practices in a French semi-mountain area.
      ;
      • Larsen M.K.
      • Nielsen J.H.
      • Butler G.
      • Leifert C.
      • Slots T.
      • Kristiansen G.H.
      • Gustafsson A.H.
      Milk quality as affected by feeding regimens in a country with climatic variation.
      , breed (
      • Soyeurt H.
      • Dardenne P.
      • Gillon A.
      • Croquet C.
      • Vanderick S.
      • Mayeres P.
      • Bertozzi C.
      • Gengler N.
      Variation in fatty acid contents of milk and milk fat within and across breeds.
      ;
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      , individual animal genetics (
      • Soyeurt H.
      • Dardenne P.
      • Dehareng F.
      • Bastin C.
      • Gengler N.
      Genetic parameters of saturated and monounsaturated fatty acid content and the ratio of saturated to unsaturated fatty acids in bovine milk.
      , stage of lactation (
      • Craninx M.
      • Steen A.
      • Van Laar H.
      • Van Nespen T.
      • Martin-Tereso J.
      • De Baets B.
      • Fievez V.
      Effect of lactation stage on the odd- and branched-chain milk fatty acids of dairy cattle under grazing and indoor conditions.
      ;
      • Stoop W.M.
      • Bovenhuis H.
      • Heck J.M.L.
      • van Arendonk J.A.M.
      Effect of lactation stage and energy status on milk fat composition of Holstein-Friesian cows.
      , management (
      • Coppa M.
      • Ferlay A.
      • Chassaing C.
      • Agabriel C.
      • Glasser F.
      • Chilliard Y.
      • Borreani G.
      • Barcarolo R.
      • Baars T.
      • Kusche D.
      • Harstad O.M.
      • Verbič J.
      • Golecký J.
      • Martin B.
      Prediction of bulk milk fatty acid composition based on farming practices collected through on-farm surveys.
      , and season (
      • Heck J.M.L.
      • van Valenberg H.J.F.
      • Dijkstra J.
      • van Hooijdonk A.C.M.
      Seasonal variation in the Dutch bovine raw milk composition.
      , as well as the interactions between them (
      • Macdonald K.A.
      • Verkerk G.A.
      • Thorrold B.S.
      • Pryce J.E.
      • Penno J.W.
      • McNaughton L.R.
      • Burton L.J.
      • Lancaster J.A.S.
      • Williamson J.H.
      • Holmes C.W.
      A comparison of three strains of Holstein-Friesian grazed on pasture and managed under different feed allowances.
      ;
      • Piccand V.
      • Cutullic E.
      • Meier S.
      • Schori F.
      • Kunz P.L.
      • Roche J.R.
      • Thomet P.
      Production and reproduction of Fleckvieh, Brown Swiss, and 2 strains of Holstein-Friesian cows in a pasture-based, seasonal-calving dairy system.
      ;
      • Stergiadis S.
      • Seal C.J.
      • Leifert C.
      • Eyre M.D.
      • Larsen M.K.
      • Butler G.
      Variation in nutritionally relevant components in retail Jersey and Guernsey whole milk.
      , affect milk composition, with many of the mechanisms behind these effects not fully understood. Therefore, when attempting to study the effect of one specific factor (e.g., diet) on cow milk composition, it is necessary to eliminate other influences. Those factors that cannot be eliminated must be accounted for and their effects considered and minimized.
      Currently, there is no evidence that consumption of organic food leads to meaningful nutritional benefits for human health (
      • Forman J.
      • Silverstein J.
      • Bhatia J.J.S.
      • Abrams S.A.
      • Corkins M.R.
      • De Ferranti S.D.
      • Golden N.H.
      • Paulson J.A.
      • Brock-Utne A.C.
      • Brumberg H.L.
      • Campbell C.C.
      • Lanphear B.P.
      • Osterhoudt K.C.
      • Sandel M.T.
      • Trasande L.
      • Wright R.O.
      Organic foods: Health and environmental advantages and disadvantages.
      ;
      • Załecka A.
      • Bügel S.
      • Paoletti F.
      • Kahl J.
      • Bonanno A.
      • Dostalova A.
      • Rahmann G.
      The influence of organic production on food quality—Research findings, gaps and future challenges.
      . Studies purportedly comparing organic and conventionally produced milk are rife with complications. To be able to determine whether organic milk differs from conventionally produced milk, all factors that influence milk composition must be identical except for the factors that specifically define the farming system (organic or conventional). If more than the system factor varies between compared milk samples, it is difficult to determine whether results derive from the differences between the farming systems or are the consequence of other factors. Recent reviews (
      • Magkos F.
      • Arvaniti F.
      • Zampelas A.
      Organic food: Nutritious food or food for thought? A review of the evidence.
      ;
      • Dangour A.D.
      • Lock K.
      • Hayter A.
      • Aikenhead A.
      • Allen E.
      • Uauy R.
      Nutrition-related health effects of organic foods: A systematic review.
      ;
      • Guéguen L.
      • Pascal G.
      An update on the nutritional and health value of organic foods.
      ;
      • Smith-Spangler C.
      • Brandeau M.L.
      • Hunter G.E.
      • Clay Bavinger J.
      • Pearson M.
      • Eschbach P.J.
      • Sundaram V.
      • Liu H.
      • Schirmer P.
      • Stave C.
      • Olkin I.
      • Bravata D.M.
      Are organic foods safer or healthier than conventional alternatives? A systematic review.
      remarked on the lack of “true” comparison in studies evaluating organic and conventionally produced foods (including milk and dairy products). Many studies comparing organic and conventionally produced milk are inadequate in their discussion of the factors actually causing the results they present. Commonly, factors that could have contributed to the reported differences (between organic and conventional milk) have not been considered (e.g., differences in diet, breed, and animal health). Most studies proclaiming a comparison of organic and conventional milk used diets that varied in their amount of fresh forage and concentrate for organic and conventional cows, respectively. Consequently, the presented results are most likely related to the effect of the differences in diet, rather than to the fact that cows consumed organic or conventionally produced feed. On the contrary, studies that identify specific production differences for organic and conventional milk (e.g., higher amount of pasture in the diet of organic cows) fail to consider the influence of the farming system (organic or conventional) on their results (
      • Palupi E.
      • Jayanegara A.
      • Ploeger A.
      • Kahl J.
      Comparison of nutritional quality between conventional and organic dairy products: A meta-analysis.
      . Additionally, comparisons among studies are problematic because it is difficult to account for any number of variables, including sampling conditions (e.g., frequency of sampling, time of sampling, samples taken from individual cows vs. bulk milk vs. multiple farms), inherent differences in farming systems between regions, levels of input, and even regulatory differences in conventional and organic production between nations.
      Regulations regarding organic dairy farming, although similar in principle, vary in detail (Table 1) between countries (e.g., pasture access and use of antibiotics). Therefore, heterogeneity of organic regulations may contribute to the variation in organic milk composition between countries.
      Table 1Country-specific regulations for organic dairy farming in regard to pasture access, forage feeding, and use of antibiotics
      CountryPasture accessForage feedAntibiotics useRegulation
      United StatesGrazed for 120 d per yearDuring grazing season, 30% of total forage intake must come from pasture.Producer must not sell, label, or represent as organic any edible product derived from any animal treated with antibiotics.Organic foods production act provisions 2014 (

      US Government Printing Office. 2014. Electronic Code of Federal Regulations: Regulations of the Department of Agriculture: Subchapter M–Organic Foods Production Act Provisions. Vol. 2014.

      Organic livestock standards for producers are compulsory.
      CanadaPasture access during grazing seasonDuring grazing season, 30% of total forage intake must come from pasture.

      60% of DM in daily rations consists of hay, fresh/dried fodder, or silage.
      Milk withdrawal time.
      Milk withdrawal time=at least 30 d or twice the specific medication’s withdrawal period, whichever is longer.


      Animals that require more than 2 treatments
      Treatments=combined parasiticides and antibiotics per year.
      shall undergo a 12-mo transition period.
      Organic Production Systems General Principles and Management Standards 2011 (
      Canadian General Standards Board
      Organic livestock standards for producers are compulsory.
      European UnionPasture access for grazing whenever conditions allow60% of DM in daily rations consists of hay, fresh/dried fodder, or silage.

      A reduction to 50% for a maximum period of 3 mo in early lactation is allowed.
      Milk withdrawal time.
      Milk withdrawal time=at least 30 d or twice the specific medication’s withdrawal period, whichever is longer.


      When animals that require more than 3 treatments,
      Treatments=combined parasiticides and antibiotics per year.
      or more than 1 course of treatment if productive lifecycle is <1 yr, the produce derived from the animal may not be sold as organic.
      Guidance document on European Union organic Standards 2010 (

      Department for Environment, Food and Rural Affairs. 2010. Guidance Document on European Union Organic Standards. Page 31. Welsh Assembly Government; Department of Agriculture and Rural Development; The Scottish Government.

      Organic livestock standards for producers are compulsory.
      JapanPasture access, no less than twice a weekFeeds other than fresh or dried fodder or silage are less than 50% of the average feed intake, in dry weight.Prescribed drugs or antibiotics are used only when therapy with veterinary drugs other than these is not effective.Japanese Agricultural Standard for Organic Livestock Products, 2005 (Ministry of Agriculture Forestry and Fisheries)
      Organic livestock standards for producers are voluntary.
      New ZealandRuminants must be grazed throughout the grazing season 150 dFor herbivores, a minimum of 50% of feed must come from pasture.Use of synthetic allopathic veterinary drugs or antibiotics will cause the animal to lose its organic status.AsureQuality Organic Standard For Primary Producers, 2013 (
      AsureQuality
      Several organic livestock standards, which are voluntary and chosen by farmer according to their organic production style.
      AustraliaGrazing of animals in natural/rangeland areas is considered part of an organic production systemAfter treatment with allopathic veterinary drugs or antibiotics, the products can be marketed as organic or bio-dynamic after a minimum management period of 180 d.National Standard for Organic and Bio-Dynamic Produce, 2013 (
      Organic Industry Standards and Certification Committee
      Organic livestock standards for producers are compulsory.
      1 Organic livestock standards for producers are compulsory.
      2 Milk withdrawal time = at least 30 d or twice the specific medication’s withdrawal period, whichever is longer.
      3 Treatments = combined parasiticides and antibiotics per year.
      4 Organic livestock standards for producers are voluntary.
      5 Several organic livestock standards, which are voluntary and chosen by farmer according to their organic production style.
      The problems outlined above account for the inability of previous studies to reach a consensus on whether compositional differences exist between organic and conventionally produced dairy foods. Consequently, comparison of research studies should be undertaken with the awareness that study-specific factors can have a significant effect on animal production and milk composition and might have contributed to reported differences.
      This review focuses on the chemical composition of bovine milk and summarizes the variety of different milk components that have been analyzed in regard to their quantitative and qualitative presence in organic and conventionally produced milk. It also aims to show how different milk components are influenced by a variety of individual factors and their interactions, and how the resulting variations can be perceived as differences between organic and conventional milks. It reinforces that these factors need to be considered when evaluating existing studies or designing comparative experiments. Variations within organic and conventional production methods have also created differences that have so far prevented development of a method to test the authenticity of organic milk products. A brief discussion of proposed tests to identify organically produced products is also included.

      Factors that influence milk composition

      Numerous and varied factors influence milk yield and composition that, ideally, should be controlled when conducting a trial examining factors that may change milk composition. These factors can seem relatively minor, but they could account for a significant amount of variation. A study conducted by
      • Roche J.R.
      • Turner L.R.
      • Lee J.M.
      • Edmeades D.C.
      • Donaghy D.J.
      • Macdonald K.A.
      • Penno J.W.
      • Berry D.P.
      Weather, herbage quality and milk production in pastoral systems. 4. Effects on dairy cattle production.
      between 1995 and 2001 showed that the combined influence of weather, herbage quality, and herbage mineral concentration explained up to 22% of the variation in dairy cattle production. In a different trial,
      • Roesch M.
      • Doherr M.G.
      • Blum J.W.
      Performance of dairy cows on Swiss farms with organic and integrated production.
      compared cow performance from organic and integrated farming systems and found that milk yield positively correlated with breed (especially Holstein), concentrate feeding, routine teat dipping, and greater outdoor access during winter independent of the system. They concluded that lower milk yields (in organic and integrated cows) are a result of the individual animal and on-farm level factors such as breed, nutrition, management, and udder health. A study by
      • Waiblinger S.
      • Menke C.
      • Coleman G.
      The relationship between attitudes, personal characteristics and behaviour of stockpeople and subsequent behaviour and production of dairy cows.
      , investigating 30 small, family-run dairy farms, suggested that milk production was lower on farms where management had negative attitudes toward interacting with cows during milking. Various factors that influence milk yield, as well as fat, protein, and lactose concentrations, at the farm and individual animal levels are compiled in Table 2.
      Table 2Summary of factors influencing milk yield, fat, protein, and lactose concentrations
      DF=Dutch Friesian; MRY=Meuse-Rhine-Yssel; GWH=Groningen White Headed; HF=Holstein-Friesian.
      FactorMilk yieldReferenceFat %ReferenceProtein %ReferenceLactose %Reference
      AltitudeHigher in highland vs. lowland
      • Bartl K.
      • Gomez C.A.
      • García M.
      • Aufdermauer T.
      • Kreuzer M.
      • Hess H.D.
      • Wettstein H.R.
      Milk fatty acid profile of Peruvian Criollo and Brown Swiss cows in response to different diet qualities fed at low and high altitude.
      BreedHigher in Holstein vs. Simmental
      • Roesch M.
      • Doherr M.G.
      • Blum J.W.
      Performance of dairy cows on Swiss farms with organic and integrated production.
      Higher in Jersey vs. DF, MRY, and GWH
      • Maurice-Van Eijndhoven M.H.T.
      • Hiemstra S.J.
      • Calus M.P.L.
      Short communication: Milk fat composition of 4 cattle breeds in the Netherlands.
      Highest in Jersey, lowest in DF
      • Maurice-Van Eijndhoven M.H.T.
      • Hiemstra S.J.
      • Calus M.P.L.
      Short communication: Milk fat composition of 4 cattle breeds in the Netherlands.
      Higher in Brown Swiss vs. Jersey
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
      Higher in HF vs. Jersey
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      Higher in Minhota vs. HF
      • Ramalho H.M.
      • Campos S.D.
      • Casal S.
      • Alves R.
      • Oliveira M.B.P.
      Lipid fraction quality of milk produced by Minhota (Portuguese autochthonous breed) compared to Holstein Friesian cow's.
      Higher in Jersey vs. HF
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      Higher in HF vs. Jersey and Brown Swiss
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
      Higher in Jersey vs. HF
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      Higher in Jersey vs. Holstein
      • Croissant A.E.
      • Washburn S.P.
      • Dean L.L.
      • Drake M.A.
      Chemical properties and consumer perception of fluid milk from conventional and pasture-based production systems.
      Higher in Jersey vs. Holstein
      • Croissant A.E.
      • Washburn S.P.
      • Dean L.L.
      • Drake M.A.
      Chemical properties and consumer perception of fluid milk from conventional and pasture-based production systems.
      Higher in Brown Swiss vs. Holstein
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
      FertilizerLower with higher N application
      • Hermansen J.E.
      • Ostersen S.
      • Aaes O.
      Effect of the levels of N fertilizer, grass and supplementary feeds on nitrogen composition and renneting properties of milk from cows at pasture.
      ;
      • Mackle T.R.
      • Parr C.R.
      • Bryant A.M.
      Nitrogen fertiliser effects on milk yield and composition, pasture intake, nitrogen and energy partitioning, and rumen fermentation parameters of dairy cows in early lactation.
      Grazing allocation (frequency)Higher if allocation every day vs. every fourth day
      • Abrahamse P.A.
      • Dijkstra J.
      • Vlaeminck B.
      • Tamminga S.
      Frequent allocation of rotationally grazed dairy cows changes grazing behavior and improves productivity.
      Higher for allocation every fourth day vs. every day
      • Abrahamse P.A.
      • Dijkstra J.
      • Vlaeminck B.
      • Tamminga S.
      Frequent allocation of rotationally grazed dairy cows changes grazing behavior and improves productivity.
      Higher if allocation every fourth day vs. every day
      • Abrahamse P.A.
      • Dijkstra J.
      • Vlaeminck B.
      • Tamminga S.
      Frequent allocation of rotationally grazed dairy cows changes grazing behavior and improves productivity.
      NS
      • Abrahamse P.A.
      • Dijkstra J.
      • Vlaeminck B.
      • Tamminga S.
      Frequent allocation of rotationally grazed dairy cows changes grazing behavior and improves productivity.
      Grazing high sugar grassesPositively correlated
      • Miller L.A.
      • Moorby J.M.
      • Davies D.R.
      • Humphreys M.O.
      • Scollan N.D.
      • MacRae J.C.
      • Theodorou M.K.
      Increased concentration of water-soluble carbohydrate in perennial ryegrass (Lolium perenne L.): Milk production from late-lactation dairy cows.
      Positively correlated
      • Roche J.R.
      • Turner L.R.
      • Lee J.M.
      • Edmeades D.C.
      • Donaghy D.J.
      • Macdonald K.A.
      • Penno J.W.
      • Berry D.P.
      Weather, herbage quality and milk production in pastoral systems. 4. Effects on dairy cattle production.
      Grazing pastureLower vs. concentrate
      • Coleman J.
      • Pierce K.M.
      • Berry D.P.
      • Brennan A.
      • Horan B.
      Increasing milk solids production across lactation through genetic selection and intensive pasture-based feed system.
      NS
      • Coleman J.
      • Pierce K.M.
      • Berry D.P.
      • Brennan A.
      • Horan B.
      Increasing milk solids production across lactation through genetic selection and intensive pasture-based feed system.
      NS
      • Croissant A.E.
      • Washburn S.P.
      • Dean L.L.
      • Drake M.A.
      Chemical properties and consumer perception of fluid milk from conventional and pasture-based production systems.
      ;
      • Coleman J.
      • Pierce K.M.
      • Berry D.P.
      • Brennan A.
      • Horan B.
      Increasing milk solids production across lactation through genetic selection and intensive pasture-based feed system.
      Unknown
      • Coleman J.
      • Pierce K.M.
      • Berry D.P.
      • Brennan A.
      • Horan B.
      Increasing milk solids production across lactation through genetic selection and intensive pasture-based feed system.
      Lower vs. TMR
      • Croissant A.E.
      • Washburn S.P.
      • Dean L.L.
      • Drake M.A.
      Chemical properties and consumer perception of fluid milk from conventional and pasture-based production systems.
      GenotypeHigher in High NA vs. High NZ and Low NA
      Low NA=national average-genetic-merit North American Holstein-Friesian; high NA=high-genetic-merit North American Holstein-Friesian; high NZ=high-genetic merit New Zealand Holstein-Friesian.
      • Coleman J.
      • Pierce K.M.
      • Berry D.P.
      • Brennan A.
      • Horan B.
      Increasing milk solids production across lactation through genetic selection and intensive pasture-based feed system.
      Higher in High NZ vs. High NA and Low NA
      • Coleman J.
      • Pierce K.M.
      • Berry D.P.
      • Brennan A.
      • Horan B.
      Increasing milk solids production across lactation through genetic selection and intensive pasture-based feed system.
      Higher in High NZ vs. High NA and Low NA
      • Coleman J.
      • Pierce K.M.
      • Berry D.P.
      • Brennan A.
      • Horan B.
      Increasing milk solids production across lactation through genetic selection and intensive pasture-based feed system.
      Higher in High NZ vs. High NA and Low NA
      • Coleman J.
      • Pierce K.M.
      • Berry D.P.
      • Brennan A.
      • Horan B.
      Increasing milk solids production across lactation through genetic selection and intensive pasture-based feed system.
      Higher in NA90 than NZ90
      NZ90=a 1990s high Breeding Worth Holstein-Friesian of New Zealand origin; NA90=a 1990s high Breeding Worth Holstein-Friesian of North American origin.
      • Macdonald K.A.
      • Verkerk G.A.
      • Thorrold B.S.
      • Pryce J.E.
      • Penno J.W.
      • McNaughton L.R.
      • Burton L.J.
      • Lancaster J.A.S.
      • Williamson J.H.
      • Holmes C.W.
      A comparison of three strains of Holstein-Friesian grazed on pasture and managed under different feed allowances.
      Higher in NZ90 than NA90
      • Macdonald K.A.
      • Verkerk G.A.
      • Thorrold B.S.
      • Pryce J.E.
      • Penno J.W.
      • McNaughton L.R.
      • Burton L.J.
      • Lancaster J.A.S.
      • Williamson J.H.
      • Holmes C.W.
      A comparison of three strains of Holstein-Friesian grazed on pasture and managed under different feed allowances.
      Higher in NZ90

      than NA90
      • Macdonald K.A.
      • Verkerk G.A.
      • Thorrold B.S.
      • Pryce J.E.
      • Penno J.W.
      • McNaughton L.R.
      • Burton L.J.
      • Lancaster J.A.S.
      • Williamson J.H.
      • Holmes C.W.
      A comparison of three strains of Holstein-Friesian grazed on pasture and managed under different feed allowances.
      Higher in NZ90

      than NA90
      • Macdonald K.A.
      • Verkerk G.A.
      • Thorrold B.S.
      • Pryce J.E.
      • Penno J.W.
      • McNaughton L.R.
      • Burton L.J.
      • Lancaster J.A.S.
      • Williamson J.H.
      • Holmes C.W.
      A comparison of three strains of Holstein-Friesian grazed on pasture and managed under different feed allowances.
      HeritabilityCorrelated
      • Soyeurt H.
      • Gillon A.
      • Vanderick S.
      • Mayeres P.
      • Bertozzi C.
      • Gengler N.
      Estimation of heritability and genetic correlations for the major fatty acids in bovine milk.
      Correlated
      • Soyeurt H.
      • Gillon A.
      • Vanderick S.
      • Mayeres P.
      • Bertozzi C.
      • Gengler N.
      Estimation of heritability and genetic correlations for the major fatty acids in bovine milk.
      Correlated
      • Soyeurt H.
      • Gillon A.
      • Vanderick S.
      • Mayeres P.
      • Bertozzi C.
      • Gengler N.
      Estimation of heritability and genetic correlations for the major fatty acids in bovine milk.
      Management attitudePositively correlated
      • Waiblinger S.
      • Menke C.
      • Coleman G.
      The relationship between attitudes, personal characteristics and behaviour of stockpeople and subsequent behaviour and production of dairy cows.
      ParityHigher
      • Roesch M.
      • Doherr M.G.
      • Blum J.W.
      Performance of dairy cows on Swiss farms with organic and integrated production.
      ;
      • Craninx M.
      • Steen A.
      • Van Laar H.
      • Van Nespen T.
      • Martin-Tereso J.
      • De Baets B.
      • Fievez V.
      Effect of lactation stage on the odd- and branched-chain milk fatty acids of dairy cattle under grazing and indoor conditions.
      Higher
      • Craninx M.
      • Steen A.
      • Van Laar H.
      • Van Nespen T.
      • Martin-Tereso J.
      • De Baets B.
      • Fievez V.
      Effect of lactation stage on the odd- and branched-chain milk fatty acids of dairy cattle under grazing and indoor conditions.
      SeasonMinimum in summer
      • Heck J.M.L.
      • van Valenberg H.J.F.
      • Dijkstra J.
      • van Hooijdonk A.C.M.
      Seasonal variation in the Dutch bovine raw milk composition.
      ;
      • Larsen M.K.
      • Fretté X.C.
      • Kristensen T.
      • Eriksen J.
      • Søegaard K.
      • Nielsen J.H.
      Fatty acid, tocopherol and carotenoid content in herbage and milk affected by sward composition and season of grazing.
      ;
      • Stergiadis S.
      • Seal C.J.
      • Leifert C.
      • Eyre M.D.
      • Larsen M.K.
      • Butler G.
      Variation in nutritionally relevant components in retail Jersey and Guernsey whole milk.
      Minimum in summer
      • Heck J.M.L.
      • van Valenberg H.J.F.
      • Dijkstra J.
      • van Hooijdonk A.C.M.
      Seasonal variation in the Dutch bovine raw milk composition.
      Minimum in autumn
      • Heck J.M.L.
      • van Valenberg H.J.F.
      • Dijkstra J.
      • van Hooijdonk A.C.M.
      Seasonal variation in the Dutch bovine raw milk composition.
      NS
      • Larsen M.K.
      • Fretté X.C.
      • Kristensen T.
      • Eriksen J.
      • Søegaard K.
      • Nielsen J.H.
      Fatty acid, tocopherol and carotenoid content in herbage and milk affected by sward composition and season of grazing.
      ;
      • Stergiadis S.
      • Seal C.J.
      • Leifert C.
      • Eyre M.D.
      • Larsen M.K.
      • Butler G.
      Variation in nutritionally relevant components in retail Jersey and Guernsey whole milk.
      SCCNegatively correlated
      • Maréchal C.L.
      • Thiéry R.
      • Vautor E.
      • Loir Y.L.
      Mastitis impact on technological properties of milk and quality of milk products—A review.
      Negatively correlated
      • Ballou L.U.
      • Pasquini M.
      • Bremel R.D.
      • Everson T.
      • Sommer D.
      Factors affecting herd milk composition and milk plasmin at four levels of somatic cell counts.
      Negatively correlated
      • Auldist M.J.
      • Hubble I.B.
      Effects of mastitis on raw milk and dairy products.
      Stage of lactationCorrelated
      • Craninx M.
      • Steen A.
      • Van Laar H.
      • Van Nespen T.
      • Martin-Tereso J.
      • De Baets B.
      • Fievez V.
      Effect of lactation stage on the odd- and branched-chain milk fatty acids of dairy cattle under grazing and indoor conditions.
      ;
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      Correlated
      • Craninx M.
      • Steen A.
      • Van Laar H.
      • Van Nespen T.
      • Martin-Tereso J.
      • De Baets B.
      • Fievez V.
      Effect of lactation stage on the odd- and branched-chain milk fatty acids of dairy cattle under grazing and indoor conditions.
      ;
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      Correlated
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      Sunlight hoursPositively correlated
      • Roche J.R.
      • Turner L.R.
      • Lee J.M.
      • Edmeades D.C.
      • Donaghy D.J.
      • Macdonald K.A.
      • Penno J.W.
      • Berry D.P.
      Weather, herbage quality and milk production in pastoral systems. 4. Effects on dairy cattle production.
      Teat dippingPositively correlated
      • Roesch M.
      • Doherr M.G.
      • Blum J.W.
      Performance of dairy cows on Swiss farms with organic and integrated production.
      1 DF = Dutch Friesian; MRY = Meuse-Rhine-Yssel; GWH = Groningen White Headed; HF = Holstein-Friesian.
      2 Low NA = national average-genetic-merit North American Holstein-Friesian; high NA = high-genetic-merit North American Holstein-Friesian; high NZ = high-genetic merit New Zealand Holstein-Friesian.
      3 NZ90 = a 1990s high Breeding Worth Holstein-Friesian of New Zealand origin; NA90 = a 1990s high Breeding Worth Holstein-Friesian of North American origin.
      The factors considered most influential, however, vary depending on study conditions and aims. Stage of lactation, for example, can be neglected when bulk milk samples are collected from a farm with an all-year-round calving system, but it becomes significant when milk samples of individual animals are taken or when block calving is practiced (
      • Nantapo C.T.W.
      • Muchenje V.
      • Hugo A.
      Atherogenicity index and health-related fatty acids in different stages of lactation from Friesian, Jersey and Friesian×Jersey cross cow milk under a pasture-based dairy system.
      . As major influences are accounted for and controlled (e.g., cows in one trial are all of one breed, with similar genetics, at the same stage of lactation, fed similar diets), previously minor factors (e.g., pasture composition) become more important.
      Analysis and (potential) alteration of milk FA composition are key areas of dairy research because of the rapid response of FA profile to changes in diet. Other factors influential for milk FA composition are breed, energy status, stage of lactation, udder health, and season. The latter predominantly reflects alterations in diet, especially when these are rich in forage. Chemical and botanical composition of fresh forages varies throughout the seasons, and conservation for hay or silage affects the nutritional value of forages. The seasonal transition of dairy cows from outdoor grazing to indoor housing and the accompanying change in diet can be observed in milk composition (Larsen et al., 2010;
      • Kuczyńska B.
      • Puppel K.
      • Gołȩbiewski M.
      • Metera E.
      • Sakowski T.
      • Słoniewski K.
      Differences in whey protein content between cow's milk collected in late pasture and early indoor feeding season from conventional and organic farms in Poland.
      . The effects of breed and season on milk fat composition are summarized in Table 3, and the effects of different forages on milk FA are listed in Table 4.
      Table 3Effect of breed and season on individual milk fatty acids
      DF=Dutch Friesian; MRY=Meuse-Rhine-Yssel; GWH=Groningen White Headed; HF=Holstein-Friesian.
      Fatty acid2BreedSeason
      EffectReferenceEffectReference
      Even-chain SFA
       C4:0 (butyric acid)Higher for DF than MRY, GWH, and Jersey
      • Maurice-Van Eijndhoven M.H.T.
      • Hiemstra S.J.
      • Calus M.P.L.
      Short communication: Milk fat composition of 4 cattle breeds in the Netherlands.
      NS
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      Higher for Brown Swiss than Jersey
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
      NS, for herbageLarsen et al. (2010)
      Higher in winter
      • Revello Chion A.
      • Tabacco E.
      • Giaccone D.
      • Peiretti P.G.
      • Battelli G.
      • Borreani G.
      Variation of fatty acid and terpene profiles in mountain milk and “Toma piemontese” cheese as affected by diet composition in different seasons.
      NS, spring or winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
      Lower in winter with maize silage and by-products, NS with pastureLarsen et al. (2010)
       C6:0 (caproic acid)Higher for DF and MRY than for GWH and Jersey
      • Maurice-Van Eijndhoven M.H.T.
      • Hiemstra S.J.
      • Calus M.P.L.
      Short communication: Milk fat composition of 4 cattle breeds in the Netherlands.
      NS
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      Higher for Jersey than Brown Swiss
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
      NS, spring or winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
      Higher in winter
      • Revello Chion A.
      • Tabacco E.
      • Giaccone D.
      • Peiretti P.G.
      • Battelli G.
      • Borreani G.
      Variation of fatty acid and terpene profiles in mountain milk and “Toma piemontese” cheese as affected by diet composition in different seasons.
       C8:0 (caprylic acid)Holstein lower than Jersey
      • Croissant A.E.
      • Washburn S.P.
      • Dean L.L.
      • Drake M.A.
      Chemical properties and consumer perception of fluid milk from conventional and pasture-based production systems.
      Lower in summer
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      NS, for herbageLarsen et al. (2010)
      NS between Minhota and HF
      • Ramalho H.M.
      • Campos S.D.
      • Casal S.
      • Alves R.
      • Oliveira M.B.P.
      Lipid fraction quality of milk produced by Minhota (Portuguese autochthonous breed) compared to Holstein Friesian cow's.
      NS, spring or winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
      Higher for DF and MRY than GWH and Jersey
      • Maurice-Van Eijndhoven M.H.T.
      • Hiemstra S.J.
      • Calus M.P.L.
      Short communication: Milk fat composition of 4 cattle breeds in the Netherlands.
      Higher in winter
      • Revello Chion A.
      • Tabacco E.
      • Giaccone D.
      • Peiretti P.G.
      • Battelli G.
      • Borreani G.
      Variation of fatty acid and terpene profiles in mountain milk and “Toma piemontese” cheese as affected by diet composition in different seasons.
       C10:0 (capric acid)Holstein lower than Jersey
      • Croissant A.E.
      • Washburn S.P.
      • Dean L.L.
      • Drake M.A.
      Chemical properties and consumer perception of fluid milk from conventional and pasture-based production systems.
      Lower in summer
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      Minhota lower than HF
      • Ramalho H.M.
      • Campos S.D.
      • Casal S.
      • Alves R.
      • Oliveira M.B.P.
      Lipid fraction quality of milk produced by Minhota (Portuguese autochthonous breed) compared to Holstein Friesian cow's.
      Higher in spring than winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
      Lowest for GWH; highest for DF
      • Maurice-Van Eijndhoven M.H.T.
      • Hiemstra S.J.
      • Calus M.P.L.
      Short communication: Milk fat composition of 4 cattle breeds in the Netherlands.
      Higher in winter
      • Revello Chion A.
      • Tabacco E.
      • Giaccone D.
      • Peiretti P.G.
      • Battelli G.
      • Borreani G.
      Variation of fatty acid and terpene profiles in mountain milk and “Toma piemontese” cheese as affected by diet composition in different seasons.
      NS between Holstein, Jersey, and Brown Swiss
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
       C12:0 (lauric acid)Holstein lower than Jersey
      • Croissant A.E.
      • Washburn S.P.
      • Dean L.L.
      • Drake M.A.
      Chemical properties and consumer perception of fluid milk from conventional and pasture-based production systems.
      Lower in summer
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      Minhota lower than HF
      • Ramalho H.M.
      • Campos S.D.
      • Casal S.
      • Alves R.
      • Oliveira M.B.P.
      Lipid fraction quality of milk produced by Minhota (Portuguese autochthonous breed) compared to Holstein Friesian cow's.
      Higher in spring than winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
      Higher for DF and MRY than GWH and Jersey
      • Maurice-Van Eijndhoven M.H.T.
      • Hiemstra S.J.
      • Calus M.P.L.
      Short communication: Milk fat composition of 4 cattle breeds in the Netherlands.
      Higher in winter
      • Revello Chion A.
      • Tabacco E.
      • Giaccone D.
      • Peiretti P.G.
      • Battelli G.
      • Borreani G.
      Variation of fatty acid and terpene profiles in mountain milk and “Toma piemontese” cheese as affected by diet composition in different seasons.
      NS between Holstein, Jersey, and Brown Swiss
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
       C14:0 (myristic acid)Higher for DF and MRY than GWH and Jersey
      • Maurice-Van Eijndhoven M.H.T.
      • Hiemstra S.J.
      • Calus M.P.L.
      Short communication: Milk fat composition of 4 cattle breeds in the Netherlands.
      Lower in summer
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      Minhota lower than HF
      • Ramalho H.M.
      • Campos S.D.
      • Casal S.
      • Alves R.
      • Oliveira M.B.P.
      Lipid fraction quality of milk produced by Minhota (Portuguese autochthonous breed) compared to Holstein Friesian cow's.
      Higher in winter
      • Revello Chion A.
      • Tabacco E.
      • Giaccone D.
      • Peiretti P.G.
      • Battelli G.
      • Borreani G.
      Variation of fatty acid and terpene profiles in mountain milk and “Toma piemontese” cheese as affected by diet composition in different seasons.
      NS between Holstein, Jersey, and Brown Swiss
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
      Highest in winter, lowest May to July
      • Kliem K.E.
      • Shingfield K.J.
      • Livingstone K.M.
      • Givens D.I.
      Seasonal variation in the fatty acid composition of milk available at retail in the United Kingdom and implications for dietary intake.
       C16:0 (palmitic acid)HF lower than Jersey
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      NS
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      NS between Minhota and HF
      • Ramalho H.M.
      • Campos S.D.
      • Casal S.
      • Alves R.
      • Oliveira M.B.P.
      Lipid fraction quality of milk produced by Minhota (Portuguese autochthonous breed) compared to Holstein Friesian cow's.
      NS
      • Revello Chion A.
      • Tabacco E.
      • Giaccone D.
      • Peiretti P.G.
      • Battelli G.
      • Borreani G.
      Variation of fatty acid and terpene profiles in mountain milk and “Toma piemontese” cheese as affected by diet composition in different seasons.
      Lowest for GWH; highest for Jersey
      • Maurice-Van Eijndhoven M.H.T.
      • Hiemstra S.J.
      • Calus M.P.L.
      Short communication: Milk fat composition of 4 cattle breeds in the Netherlands.
      May higher than August when lower content of lucerneLarsen et al. (2010)
      NS between Holstein, Jersey, and Brown Swiss
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
      Higher in winter than spring
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
      Highest in winter, lowest May to July
      • Kliem K.E.
      • Shingfield K.J.
      • Livingstone K.M.
      • Givens D.I.
      Seasonal variation in the fatty acid composition of milk available at retail in the United Kingdom and implications for dietary intake.
       C18:0 (stearic acid)NS between Minhota and HF
      • Ramalho H.M.
      • Campos S.D.
      • Casal S.
      • Alves R.
      • Oliveira M.B.P.
      Lipid fraction quality of milk produced by Minhota (Portuguese autochthonous breed) compared to Holstein Friesian cow's.
      Higher in summer
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      ;

      • Revello Chion A.
      • Tabacco E.
      • Giaccone D.
      • Peiretti P.G.
      • Battelli G.
      • Borreani G.
      Variation of fatty acid and terpene profiles in mountain milk and “Toma piemontese” cheese as affected by diet composition in different seasons.
      No difference for DF, MRY, GWH,

      and Jersey
      • Maurice-Van Eijndhoven M.H.T.
      • Hiemstra S.J.
      • Calus M.P.L.
      Short communication: Milk fat composition of 4 cattle breeds in the Netherlands.
      May and August lower than June when lower content of chicory and lucerne
      • Larsen M.K.
      • Fretté X.C.
      • Kristensen T.
      • Eriksen J.
      • Søegaard K.
      • Nielsen J.H.
      Fatty acid, tocopherol and carotenoid content in herbage and milk affected by sward composition and season of grazing.
      NS between HF and Jersey
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      NS, spring or winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
      Highest in June, lowest in October
      • Kliem K.E.
      • Shingfield K.J.
      • Livingstone K.M.
      • Givens D.I.
      Seasonal variation in the fatty acid composition of milk available at retail in the United Kingdom and implications for dietary intake.
      Odd-chain SFA
       C13:0NS between Holstein, Jersey, and Brown Swiss
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
      Lower in summer
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
       C15:0Minhota higher than HF
      • Ramalho H.M.
      • Campos S.D.
      • Casal S.
      • Alves R.
      • Oliveira M.B.P.
      Lipid fraction quality of milk produced by Minhota (Portuguese autochthonous breed) compared to Holstein Friesian cow's.
      Lower in summer
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      HF higher than Jersey
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      Higher in spring than winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
      NS between Holstein, Jersey, and Brown Swiss
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
      Higher in summer
      • Revello Chion A.
      • Tabacco E.
      • Giaccone D.
      • Peiretti P.G.
      • Battelli G.
      • Borreani G.
      Variation of fatty acid and terpene profiles in mountain milk and “Toma piemontese” cheese as affected by diet composition in different seasons.
       C17:0NS between Holstein, Jersey, and Brown Swiss
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
      NS
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      Higher in spring than winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
      Branched-chain FA
       C13:0 isoLower in summer
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
       C14:0 isoHigher in spring than winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
       C15:0 isoMinhota higher than HF
      • Ramalho H.M.
      • Campos S.D.
      • Casal S.
      • Alves R.
      • Oliveira M.B.P.
      Lipid fraction quality of milk produced by Minhota (Portuguese autochthonous breed) compared to Holstein Friesian cow's.
      Higher in spring than winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
       C15:0 anteisoNS between Minhota and HF
      • Ramalho H.M.
      • Campos S.D.
      • Casal S.
      • Alves R.
      • Oliveira M.B.P.
      Lipid fraction quality of milk produced by Minhota (Portuguese autochthonous breed) compared to Holstein Friesian cow's.
      NS, spring or winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
       C16:0 isoMinhota higher than HF
      • Ramalho H.M.
      • Campos S.D.
      • Casal S.
      • Alves R.
      • Oliveira M.B.P.
      Lipid fraction quality of milk produced by Minhota (Portuguese autochthonous breed) compared to Holstein Friesian cow's.
       C17:0 isoNS, spring or winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
       C17:0 anteisoHigher in spring than winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
      Unsaturated FA
       C14:1 cis-9 (myristoleic acid)NS between Holstein and Jersey
      • Croissant A.E.
      • Washburn S.P.
      • Dean L.L.
      • Drake M.A.
      Chemical properties and consumer perception of fluid milk from conventional and pasture-based production systems.
      Higher in winter
      • Revello Chion A.
      • Tabacco E.
      • Giaccone D.
      • Peiretti P.G.
      • Battelli G.
      • Borreani G.
      Variation of fatty acid and terpene profiles in mountain milk and “Toma piemontese” cheese as affected by diet composition in different seasons.
      NS between Minhota and HF
      • Ramalho H.M.
      • Campos S.D.
      • Casal S.
      • Alves R.
      • Oliveira M.B.P.
      Lipid fraction quality of milk produced by Minhota (Portuguese autochthonous breed) compared to Holstein Friesian cow's.
      HF higher than Jersey
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
       C16:1 cis-9 (palmitoleic acid)Holstein higher than Jersey
      • Croissant A.E.
      • Washburn S.P.
      • Dean L.L.
      • Drake M.A.
      Chemical properties and consumer perception of fluid milk from conventional and pasture-based production systems.
      Higher in winter than spring
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
      Minhota higher than HF
      • Ramalho H.M.
      • Campos S.D.
      • Casal S.
      • Alves R.
      • Oliveira M.B.P.
      Lipid fraction quality of milk produced by Minhota (Portuguese autochthonous breed) compared to Holstein Friesian cow's.
      Higher in winter
      • Revello Chion A.
      • Tabacco E.
      • Giaccone D.
      • Peiretti P.G.
      • Battelli G.
      • Borreani G.
      Variation of fatty acid and terpene profiles in mountain milk and “Toma piemontese” cheese as affected by diet composition in different seasons.
       C18:1 trans-9 (elaidic acid)NS between Holstein, Jersey, and Brown Swiss
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
      Higher in winter than spring
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
       C18:1 trans-10NS spring or winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
       C18:1 trans-11 (vaccenic acid)NS between Holstein and Jersey
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      NS
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      Higher in Holstein than Brown Swiss
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
      Total trans 18:1 highest Aug/Sep/Oct
      • Dunshea F.R.
      • Walker G.P.
      • Ostrowska E.
      • Doyle P.T.
      Seasonal variation in the concentrations of conjugated linoleic and trans fatty acids in milk fat from commercial dairy farms is associated with pasture and grazing management and supplementary feeding practices.
      Higher in spring than winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
      Higher in summer
      • Revello Chion A.
      • Tabacco E.
      • Giaccone D.
      • Peiretti P.G.
      • Battelli G.
      • Borreani G.
      Variation of fatty acid and terpene profiles in mountain milk and “Toma piemontese” cheese as affected by diet composition in different seasons.
       C18:1 cis-9 (oleic acid)Holstein higher than Jersey
      • Croissant A.E.
      • Washburn S.P.
      • Dean L.L.
      • Drake M.A.
      Chemical properties and consumer perception of fluid milk from conventional and pasture-based production systems.
      NS
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      HF higher than Jersey
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      Higher in winter than spring
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
      Higher in Brown Swiss than Jersey

      and Holstein
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
      Lowest in May/lowest content of chicory and lucerne
      • Larsen M.K.
      • Fretté X.C.
      • Kristensen T.
      • Eriksen J.
      • Søegaard K.
      • Nielsen J.H.
      Fatty acid, tocopherol and carotenoid content in herbage and milk affected by sward composition and season of grazing.
      Higher in summer
      • Revello Chion A.
      • Tabacco E.
      • Giaccone D.
      • Peiretti P.G.
      • Battelli G.
      • Borreani G.
      Variation of fatty acid and terpene profiles in mountain milk and “Toma piemontese” cheese as affected by diet composition in different seasons.
       C18:2 cis-9,12 (linoleic acid)Holstein higher than Jersey
      • Croissant A.E.
      • Washburn S.P.
      • Dean L.L.
      • Drake M.A.
      Chemical properties and consumer perception of fluid milk from conventional and pasture-based production systems.
      Higher in summer
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      NS between Holstein and Jersey
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      Highest in May/highest concentration of red clover
      • Larsen M.K.
      • Fretté X.C.
      • Kristensen T.
      • Eriksen J.
      • Søegaard K.
      • Nielsen J.H.
      Fatty acid, tocopherol and carotenoid content in herbage and milk affected by sward composition and season of grazing.
      NS between Holstein, Jersey, and Brown Swiss
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
      Higher in summer
      • Revello Chion A.
      • Tabacco E.
      • Giaccone D.
      • Peiretti P.G.
      • Battelli G.
      • Borreani G.
      Variation of fatty acid and terpene profiles in mountain milk and “Toma piemontese” cheese as affected by diet composition in different seasons.
       C18:2 cis-9,trans-11 (CLA)HF higher than Jersey
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      NS
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      NS between Holstein, Jersey, and Brown Swiss
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
      Total cis/trans 18:2 highest

      Aug/Sep/Oct
      • Dunshea F.R.
      • Walker G.P.
      • Ostrowska E.
      • Doyle P.T.
      Seasonal variation in the concentrations of conjugated linoleic and trans fatty acids in milk fat from commercial dairy farms is associated with pasture and grazing management and supplementary feeding practices.
      Higher in spring than winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
      Higher in summer
      • Revello Chion A.
      • Tabacco E.
      • Giaccone D.
      • Peiretti P.G.
      • Battelli G.
      • Borreani G.
      Variation of fatty acid and terpene profiles in mountain milk and “Toma piemontese” cheese as affected by diet composition in different seasons.
       C18:3 cis-9,12,15 (α-linolenic acid)NS between Holstein and Jersey
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      NS
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      NS between Holstein, Jersey, and Brown Swiss
      • Carroll S.M.
      • DePeters E.J.
      • Taylor S.J.
      • Rosenberg M.
      • Perez-Monti H.
      • Capps V.A.
      Milk composition of Holstein, Jersey, and Brown Swiss cows in response to increasing levels of dietary fat.
      Higher in spring than winter
      • Rego O.A.
      • Rosa H.J.D.
      • Regalo S.M.
      • Alves S.P.
      • Alfaia C.M.M.
      • Prates J.A.M.
      • Vouzela C.M.
      • Bessa R.J.B.
      Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores.
      Highest in May/highest concentration of red clover,

      lowest in white clover
      • Larsen M.K.
      • Fretté X.C.
      • Kristensen T.
      • Eriksen J.
      • Søegaard K.
      • Nielsen J.H.
      Fatty acid, tocopherol and carotenoid content in herbage and milk affected by sward composition and season of grazing.
      1 DF = Dutch Friesian; MRY = Meuse-Rhine-Yssel; GWH = Groningen White Headed; HF = Holstein-Friesian.
      Table 4Effect of different forages on individual milk fatty acids
      Fatty acidIncreased in
      WC=white clover; RC=red clover.
      Reference
      Even-chain SFA
       C4:0 (butyric acid)Alpine pasture vs. pasture
      • Collomb M.
      • Bütikofer U.
      • Spahni M.
      • Jeangros B.
      • Bosset J.O.
      Fatty acid and glyceride composition of cow's milk fat in high-and lowland regions.
      Pasture hay vs. grass silage
      • Baars T.
      • Wohlers J.
      • Kusche D.
      • Jahreis G.
      Experimental improvement of cow milk fatty acid composition in organic winter diets.
       C6:0 (caproic acid)Pasture hay vs. grass silage
      • Baars T.
      • Wohlers J.
      • Kusche D.
      • Jahreis G.
      Experimental improvement of cow milk fatty acid composition in organic winter diets.
       C16:0 (palmitic acid)NS: WC or RC silage
      • Steinshamn H.
      • Thuen E.
      White or red clover-grass silage in organic dairy milk production: Grassland productivity and milk production responses with different levels of concentrate.
      Hay or grass silage vs. pasture
      • Villeneuve M.P.
      • Lebeuf Y.
      • Gervais R.
      • Tremblay G.F.
      • Vuillemard J.C.
      • Fortin J.
      • Chouinard P.Y.
      Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage.
      Maize silage vs. pasture
      • Croissant A.E.
      • Washburn S.P.
      • Dean L.L.
      • Drake M.A.
      Chemical properties and consumer perception of fluid milk from conventional and pasture-based production systems.
       C18:0 (stearic acid)Pasture vs. grass silage
      • Elgersma A.
      • Ellen G.
      • Van Der Horst H.
      • Boer H.
      • Dekker P.R.
      • Tamminga S.
      Quick changes in milk fat composition from cows after transition from fresh grass to a silage diet.
      NS: WC silage or RC silage
      • Steinshamn H.
      • Thuen E.
      White or red clover-grass silage in organic dairy milk production: Grassland productivity and milk production responses with different levels of concentrate.
      RC silage vs. WC silage
      • Wiking L.
      • Theil P.K.
      • Nielsen J.H.
      • Sørensen M.T.
      Effect of grazing fresh legumes or feeding silage on fatty acids and enzymes involved in the synthesis of milk fat in dairy cows.
      Odd-chain SFA
       C13:0Pasture hay vs. grass silage
      • Baars T.
      • Wohlers J.
      • Kusche D.
      • Jahreis G.
      Experimental improvement of cow milk fatty acid composition in organic winter diets.
      ;
      • Villeneuve M.P.
      • Lebeuf Y.
      • Gervais R.
      • Tremblay G.F.
      • Vuillemard J.C.
      • Fortin J.
      • Chouinard P.Y.
      Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage.
       C17:0Maize silage vs. grass silage
      • Vlaeminck B.
      • Fievez V.
      • Cabrita A.R.J.
      • Fonseca A.J.M.
      • Dewhurst R.J.
      Factors affecting odd- and branched-chain fatty acids in milk: A review.
      Branched-chain FA
       C14:0 isoPasture or hay vs. grass silage
      • Villeneuve M.P.
      • Lebeuf Y.
      • Gervais R.
      • Tremblay G.F.
      • Vuillemard J.C.
      • Fortin J.
      • Chouinard P.Y.
      Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage.
       C15:0 isoGrass silage vs. maize silage
      • Vlaeminck B.
      • Fievez V.
      • Cabrita A.R.J.
      • Fonseca A.J.M.
      • Dewhurst R.J.
      Factors affecting odd- and branched-chain fatty acids in milk: A review.
       C15:0 anteisoGrass silage vs. maize silage
      • Vlaeminck B.
      • Fievez V.
      • Cabrita A.R.J.
      • Fonseca A.J.M.
      • Dewhurst R.J.
      Factors affecting odd- and branched-chain fatty acids in milk: A review.
      Pasture hay vs. grass silage
      • Baars T.
      • Wohlers J.
      • Kusche D.
      • Jahreis G.
      Experimental improvement of cow milk fatty acid composition in organic winter diets.
       C16:0 isoGrass silage vs. maize silage
      • Vlaeminck B.
      • Fievez V.
      • Cabrita A.R.J.
      • Fonseca A.J.M.
      • Dewhurst R.J.
      Factors affecting odd- and branched-chain fatty acids in milk: A review.
      Pasture or hay vs. grass silage
      • Baars T.
      • Wohlers J.
      • Kusche D.
      • Jahreis G.
      Experimental improvement of cow milk fatty acid composition in organic winter diets.
      ;
      • Villeneuve M.P.
      • Lebeuf Y.
      • Gervais R.
      • Tremblay G.F.
      • Vuillemard J.C.
      • Fortin J.
      • Chouinard P.Y.
      Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage.
       C16:0 anteisoPasture hay vs. grass silage
      • Baars T.
      • Wohlers J.
      • Kusche D.
      • Jahreis G.
      Experimental improvement of cow milk fatty acid composition in organic winter diets.
       C17:0 isoMaize silage vs. grass silage
      • Vlaeminck B.
      • Fievez V.
      • Cabrita A.R.J.
      • Fonseca A.J.M.
      • Dewhurst R.J.
      Factors affecting odd- and branched-chain fatty acids in milk: A review.
      Pasture vs. hay
      • Villeneuve M.P.
      • Lebeuf Y.
      • Gervais R.
      • Tremblay G.F.
      • Vuillemard J.C.
      • Fortin J.
      • Chouinard P.Y.
      Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage.
       C17:0 anteisoMaize silage vs. grass silage
      • Vlaeminck B.
      • Fievez V.
      • Cabrita A.R.J.
      • Fonseca A.J.M.
      • Dewhurst R.J.
      Factors affecting odd- and branched-chain fatty acids in milk: A review.
      Pasture or hay vs. grass silage
      • Villeneuve M.P.
      • Lebeuf Y.
      • Gervais R.
      • Tremblay G.F.
      • Vuillemard J.C.
      • Fortin J.
      • Chouinard P.Y.
      Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage.
       C18:0 isoGrass silage vs. maize silage
      • Kliem K.E.
      • Morgan R.
      • Humphries D.J.
      • Shingfield K.J.
      • Givens D.I.
      Effect of replacing grass silage with maize silage in the diet on bovine milk fatty acid composition.
      Unsaturated FA
       C18:1 trans-9 (elaidic acid)Pasture vs. WC silage
      • Wijesundera C.
      • Shen Z.
      • Wales W.J.
      • Dalley D.E.
      Effect of cereal grain and fibre supplements on the fatty acid composition of milk fat of grazing dairy cows in early lactation.
      ;
      • Elgersma A.
      • Ellen G.
      • Van Der Horst H.
      • Boer H.
      • Dekker P.R.
      • Tamminga S.
      Quick changes in milk fat composition from cows after transition from fresh grass to a silage diet.
      Grass silage vs. WC and RC silage
      • Wiking L.
      • Theil P.K.
      • Nielsen J.H.
      • Sørensen M.T.
      Effect of grazing fresh legumes or feeding silage on fatty acids and enzymes involved in the synthesis of milk fat in dairy cows.
      Pasture vs. grass silage or hay
      • Villeneuve M.P.
      • Lebeuf Y.
      • Gervais R.
      • Tremblay G.F.
      • Vuillemard J.C.
      • Fortin J.
      • Chouinard P.Y.
      Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage.
      Maize silage
      • Wijesundera C.
      • Shen Z.
      • Wales W.J.
      • Dalley D.E.
      Effect of cereal grain and fibre supplements on the fatty acid composition of milk fat of grazing dairy cows in early lactation.
      ;
      • Kliem K.E.
      • Morgan R.
      • Humphries D.J.
      • Shingfield K.J.
      • Givens D.I.
      Effect of replacing grass silage with maize silage in the diet on bovine milk fatty acid composition.
       C18:1 trans-10Maize silage vs. pasture
      • Kliem K.E.
      • Morgan R.
      • Humphries D.J.
      • Shingfield K.J.
      • Givens D.I.
      Effect of replacing grass silage with maize silage in the diet on bovine milk fatty acid composition.
      Pasture vs. grass silage or hay
      • Villeneuve M.P.
      • Lebeuf Y.
      • Gervais R.
      • Tremblay G.F.
      • Vuillemard J.C.
      • Fortin J.
      • Chouinard P.Y.
      Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage.
       C18:1 trans-11 (vaccenic acid)Pasture vs. maize silage
      • Elgersma A.
      • Ellen G.
      • Van Der Horst H.
      • Boer H.
      • Dekker P.R.
      • Tamminga S.
      Quick changes in milk fat composition from cows after transition from fresh grass to a silage diet.
      ;
      • Slots T.
      • Butler G.
      • Leifert C.
      • Kristensen T.
      • Skibsted L.H.
      • Nielsen J.H.
      Potentials to differentiate milk composition by different feeding strategies.
      Pasture vs. grass silage vs. hay
      • Villeneuve M.P.
      • Lebeuf Y.
      • Gervais R.
      • Tremblay G.F.
      • Vuillemard J.C.
      • Fortin J.
      • Chouinard P.Y.
      Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage.
      WC and RC pasture vs. maize silage
      • Wiking L.
      • Theil P.K.
      • Nielsen J.H.
      • Sørensen M.T.
      Effect of grazing fresh legumes or feeding silage on fatty acids and enzymes involved in the synthesis of milk fat in dairy cows.
      NS: grass or maize silage
      • Kliem K.E.
      • Morgan R.
      • Humphries D.J.
      • Shingfield K.J.
      • Givens D.I.
      Effect of replacing grass silage with maize silage in the diet on bovine milk fatty acid composition.
       C18:1 cis-9 (oleic acid)Pasture
      • Ellis K.A.
      • Innocent G.
      • Grove-White D.
      • Cripps P.
      • McLean W.G.
      • Howard C.V.
      • Mihm M.
      Comparing the fatty acid composition of organic and conventional milk.
      ;
      • Croissant A.E.
      • Washburn S.P.
      • Dean L.L.
      • Drake M.A.
      Chemical properties and consumer perception of fluid milk from conventional and pasture-based production systems.
      ;
      • Heck J.M.L.
      • van Valenberg H.J.F.
      • Dijkstra J.
      • van Hooijdonk A.C.M.
      Seasonal variation in the Dutch bovine raw milk composition.
      Pasture vs. grass silage
      • Elgersma A.
      • Ellen G.
      • Van Der Horst H.
      • Boer H.
      • Dekker P.R.
      • Tamminga S.
      Quick changes in milk fat composition from cows after transition from fresh grass to a silage diet.
      Pasture vs. hay
      • Villeneuve M.P.
      • Lebeuf Y.
      • Gervais R.
      • Tremblay G.F.
      • Vuillemard J.C.
      • Fortin J.
      • Chouinard P.Y.
      Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage.
      NS: grass silage vs. maize silage
      • Kliem K.E.
      • Morgan R.
      • Humphries D.J.
      • Shingfield K.J.
      • Givens D.I.
      Effect of replacing grass silage with maize silage in the diet on bovine milk fatty acid composition.
       C18:1 cis-11WC pasture
      • Ellis K.A.
      • Innocent G.
      • Grove-White D.
      • Cripps P.
      • McLean W.G.
      • Howard C.V.
      • Mihm M.
      Comparing the fatty acid composition of organic and conventional milk.
       C18:2 cis-9,12 (linoleic acid)Maize silage vs. fresh pasture
      • Kliem K.E.
      • Morgan R.
      • Humphries D.J.
      • Shingfield K.J.
      • Givens D.I.
      Effect of replacing grass silage with maize silage in the diet on bovine milk fatty acid composition.
      ;
      • Slots T.
      • Butler G.
      • Leifert C.
      • Kristensen T.
      • Skibsted L.H.
      • Nielsen J.H.
      Potentials to differentiate milk composition by different feeding strategies.
      Pasture vs. grass silage or hay
      • Villeneuve M.P.
      • Lebeuf Y.
      • Gervais R.
      • Tremblay G.F.
      • Vuillemard J.C.
      • Fortin J.
      • Chouinard P.Y.
      Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage.
       C18:2 cis-9,trans-11 (CLA)Pasture
      • Elgersma A.
      • Ellen G.
      • Van Der Horst H.
      • Boer H.
      • Dekker P.R.
      • Tamminga S.
      Quick changes in milk fat composition from cows after transition from fresh grass to a silage diet.
      ;

      • Croissant A.E.
      • Washburn S.P.
      • Dean L.L.
      • Drake M.A.
      Chemical properties and consumer perception of fluid milk from conventional and pasture-based production systems.
      ;
      • Slots T.
      • Butler G.
      • Leifert C.
      • Kristensen T.
      • Skibsted L.H.
      • Nielsen J.H.
      Potentials to differentiate milk composition by different feeding strategies.
      ;

      • Heck J.M.L.
      • van Valenberg H.J.F.
      • Dijkstra J.
      • van Hooijdonk A.C.M.
      Seasonal variation in the Dutch bovine raw milk composition.
      ;
      • Prandini A.
      • Sigolo S.
      • Piva G.
      Conjugated linoleic acid (CLA) and fatty acid composition of milk, curd and Grana Padano cheese in conventional and organic farming systems.
      Pasture vs. grass silage
      • Ellis K.A.
      • Innocent G.
      • Grove-White D.
      • Cripps P.
      • McLean W.G.
      • Howard C.V.
      • Mihm M.
      Comparing the fatty acid composition of organic and conventional milk.
      ;
      • Villeneuve M.P.
      • Lebeuf Y.
      • Gervais R.
      • Tremblay G.F.
      • Vuillemard J.C.
      • Fortin J.
      • Chouinard P.Y.
      Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage.
      Pasture or grass silage vs. hay
      • Villeneuve M.P.
      • Lebeuf Y.
      • Gervais R.
      • Tremblay G.F.
      • Vuillemard J.C.
      • Fortin J.
      • Chouinard P.Y.
      Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage.
      RC and WC pasture vs. maize silage
      • Wiking L.
      • Theil P.K.
      • Nielsen J.H.
      • Sørensen M.T.
      Effect of grazing fresh legumes or feeding silage on fatty acids and enzymes involved in the synthesis of milk fat in dairy cows.
      Hay
      • Prandini A.
      • Sigolo S.
      • Piva G.
      Conjugated linoleic acid (CLA) and fatty acid composition of milk, curd and Grana Padano cheese in conventional and organic farming systems.
       C18:3 cis-9,12,15 (α-linolenic acid)Pasture
      • Lourenço M.
      • Van Ranst G.
      • Vlaeminck B.
      • De Smet S.
      • Fievez V.
      Influence of different dietary forages on the fatty acid composition of rumen digesta as well as ruminant meat and milk.
      ;
      • Prandini A.
      • Sigolo S.
      • Piva G.
      Conjugated linoleic acid (CLA) and fatty acid composition of milk, curd and Grana Padano cheese in conventional and organic farming systems.
      ;
      • Slots T.
      • Butler G.
      • Leifert C.
      • Kristensen T.
      • Skibsted L.H.
      • Nielsen J.H.
      Potentials to differentiate milk composition by different feeding strategies.
      ;
      • Schröder M.
      • Yousefi F.
      • Vetter W.
      Investigating the day-to-day variations of potential marker fatty acids for organic milk in milk from conventionally and organically raised cows.
      RC pasture
      • Lourenço M.
      • Van Ranst G.
      • Vlaeminck B.
      • De Smet S.
      • Fievez V.
      Influence of different dietary forages on the fatty acid composition of rumen digesta as well as ruminant meat and milk.
      ;
      • Butler G.
      • Nielsen J.H.
      • Larsen M.K.
      • Rehberger B.
      • Stergiadis S.
      • Canever A.
      • Leifert C.
      The effects of dairy management and processing on quality characteristics of milk and dairy products.
      RC pasture vs. WC silage
      • Steinshamn H.
      • Thuen E.
      White or red clover-grass silage in organic dairy milk production: Grassland productivity and milk production responses with different levels of concentrate.
      ;
      • Slots T.
      • Butler G.
      • Leifert C.
      • Kristensen T.
      • Skibsted L.H.
      • Nielsen J.H.
      Potentials to differentiate milk composition by different feeding strategies.
      WC pasture or WC silage
      • Ellis K.A.
      • Innocent G.
      • Grove-White D.
      • Cripps P.
      • McLean W.G.
      • Howard C.V.
      • Mihm M.
      Comparing the fatty acid composition of organic and conventional milk.
      ;
      • Slots T.
      • Butler G.
      • Leifert C.
      • Kristensen T.
      • Skibsted L.H.
      • Nielsen J.H.
      Potentials to differentiate milk composition by different feeding strategies.
      RC silage
      • Elgersma A.
      • Tamminga S.
      • Ellen G.
      Modifying milk composition through forage.
      ;
      • Ellis K.A.
      • Innocent G.
      • Grove-White D.
      • Cripps P.
      • McLean W.G.
      • Howard C.V.
      • Mihm M.
      Comparing the fatty acid composition of organic and conventional milk.
      ;
      • Slots T.
      • Butler G.
      • Leifert C.
      • Kristensen T.
      • Skibsted L.H.
      • Nielsen J.H.
      Potentials to differentiate milk composition by different feeding strategies.
      Pasture vs. hay vs. grass silage
      • Villeneuve M.P.
      • Lebeuf Y.
      • Gervais R.
      • Tremblay G.F.
      • Vuillemard J.C.
      • Fortin J.
      • Chouinard P.Y.
      Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage.
      Hay
      • Slots T.
      • Butler G.
      • Leifert C.
      • Kristensen T.
      • Skibsted L.H.
      • Nielsen J.H.
      Potentials to differentiate milk composition by different feeding strategies.
      1 WC = white clover; RC = red clover.

      Conventional versus organic milk: main components

      Milk Yield

      Despite the existence of highly specialized, grassland-based, organic farms with cows producing more than 9,000 kg of fluid milk per year (
      • Muller-Lindenlauf M.
      • Deittert C.
      • Kopke U.
      Assessment of environmental effects, animal welfare and milk quality among organic dairy farms.
      , milk production from organically reared cows is lower, on average, than that from conventional cows (
      • Sundberg T.
      • Berglund B.
      • Rydhmer L.
      • Strandberg E.
      Fertility, somatic cell count and milk production in Swedish organic and conventional dairy herds.
      . These differences are significant, with organic herds achieving 85% (range: 72 to 91%) of the yields recorded for conventional herds (
      • Bilik K.
      • Lopuszanska-Rusek M.
      Effect of organic and conventional feeding of Red-and-White cows on productivity and milk composition.
      ;
      • Müller U.
      • Sauerwein H.
      A comparison of somatic cell count between organic and conventional dairy cow herds in West Germany stressing dry period related changes.
      ;
      • Stiglbauer K.E.
      • Cicconi-Hogan K.M.
      • Richert R.
      • Schukken Y.H.
      • Ruegg P.L.
      • Gamroth M.
      Assessment of herd management on organic and conventional dairy farms in the United States.
      . Decreased production under organic management can be traced to lower energy intake, through either less concentrate feeding (
      • Garmo R.T.
      • Waage S.
      • Sviland S.
      • Henriksen B.I.F.
      • Østerås O.
      • Reksen O.
      Reproductive performance, udder health, and antibiotic resistance in mastitis bacteria isolated from Norwegian Red cows in conventional and organic farming.
      ;
      • Stiglbauer K.E.
      • Cicconi-Hogan K.M.
      • Richert R.
      • Schukken Y.H.
      • Ruegg P.L.
      • Gamroth M.
      Assessment of herd management on organic and conventional dairy farms in the United States.
      or lower energy content in forages from organic systems. This is exemplified by
      • Gruber L.
      • Steinwender R.
      • Guggenberger T.
      • Häusler J.
      • Schauer A.
      Comparison of organic and conventional farming on a grassland farm. Second Communication: Feed intake, milk yield, health and fertility parameters.
      , who conducted a 6-yr study with nearly identical diets for organic and conventional cows. They demonstrated that milk yields per cow and year were identical for both herds, but milk production per area grazed was reduced in the organic herd because of lower DM yields from organic pasture and, therefore, lower stocking rates per hectare. Consequently, diets similar in composition and ME content had the same effect on milk production, independent of whether the farming system was organic or conventional.

      Milk Fat Content

      Results of research studies examining the fat content in organic and conventional milks are ambivalent.

      Zagorska, J., and I. Ciprovica. 2008. The chemical composition of organic and conventional milk in Latvia. Proc. 3rd Baltic Conference on Food Science and Technology. (FOODBALT-2008). Latvia University of Agriculture Faculty of Food Technology. 10–14.

      and
      • Anacker G.
      Differences between composition of organic milk and conventional milk.
      found increased fat content in organic milk, whereas trials undertaken by
      • Sundberg T.
      • Berglund B.
      • Rydhmer L.
      • Strandberg E.
      Fertility, somatic cell count and milk production in Swedish organic and conventional dairy herds.
      ,
      • Hanus O.
      • Vorlicek Z.
      • Sojkova K.
      • Rozsypal R.
      • Vyletelova M.
      • Roubal P.
      • Gencurova V.
      • Pozdisek J.
      • Landova H.
      A comparison of selected milk indicators in organic herds with conventional herd as reference.
      , and
      • Kuczyńska B.
      • Puppel K.
      • Gołȩbiewski M.
      • Metera E.
      • Sakowski T.
      • Słoniewski K.
      Differences in whey protein content between cow's milk collected in late pasture and early indoor feeding season from conventional and organic farms in Poland.
      observed higher fat percentage in conventional milk. Samples of retail milk collected during October and November 2006 in the United States showed no significant difference for fat percentage between the 2 milk varieties (
      • Vicini J.
      • Etherton T.
      • Kris-Etherton P.
      • Ballam J.
      • Denham S.
      • Staub R.
      • Goldstein D.
      • Cady R.
      • McGrath M.
      • Lucy M.
      Survey of retail milk composition as affected by label claims regarding farm-management practices.
      . This result might be due to the federal standards for butterfat content for fluid milk products.
      • Müller U.
      • Sauerwein H.
      A comparison of somatic cell count between organic and conventional dairy cow herds in West Germany stressing dry period related changes.
      analyzed bulk milk samples of 35 organic and 33 conventional farms during 2002 and 2004 and reported similar amounts of milk fat between the 2 farming systems. Reasons for the reported differences can be diverse, with only a few publications mentioning potential causes. Higher fat concentration in milk from organic compared with conventional farms could have been caused by a preference for non-Holstein breeds in organic herds (
      • Nauta W.J.
      • Baars T.
      • Saatkamp H.
      • Weenink D.
      • Roep D.
      Farming strategies in organic dairy farming: Effects on breeding goal and choice of breed. An explorative study.
      , resulting in a higher number of Jersey and other breeds (
      • Palladino R.A.
      • Buckley F.
      • Prendiville R.
      • Murphy J.J.
      • Callan J.
      • Kenny D.A.
      A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions.
      . An increase in starch-based concentrates has been associated with a decline in milk fat concentration. Greater amounts of starch-based concentrates are commonly associated with diets of conventionally farmed dairy cows compared with organic cows (
      • Rosati A.
      • Aumaitre A.
      Organic dairy farming in Europe.
      , because organic farming regulations restrict the usage of concentrates. Alternatively, an increase in milk fat percentage in milk from conventional farms may indicate a diet enriched with fat supplements (
      • Vyas D.
      • Teter B.B.
      • Erdman R.A.
      Milk fat responses to dietary supplementation of short- and medium-chain fatty acids in lactating dairy cows.
      ;
      • Lock A.L.
      • Preseault C.L.
      • Rico J.E.
      • DeLand K.E.
      • Allen M.S.
      Feeding a C16:0-enriched fat supplement increased the yield of milk fat and improved conversion of feed to milk.
      . A negative energy balance, predominantly found during the early stages of lactation and the winter period in low-input organic cows (
      • Trachsel P.
      • Busato A.
      • Blum J.W.
      Body conditions scores of dairy cattle in organic farms.
      , might also affect fat percentage in milk (
      • Gross J.
      • Van Dorland H.A.
      • Bruckmaier R.M.
      • Schwarz F.J.
      Milk fatty acid profile related to energy balance in dairy cows.
      . Additionally, a higher parity average (
      • Craninx M.
      • Steen A.
      • Van Laar H.
      • Van Nespen T.
      • Martin-Tereso J.
      • De Baets B.
      • Fievez V.
      Effect of lactation stage on the odd- and branched-chain milk fatty acids of dairy cattle under grazing and indoor conditions.
      , variations in heritability (
      • Soyeurt H.
      • Gillon A.
      • Vanderick S.
      • Mayeres P.
      • Bertozzi C.
      • Gengler N.
      Estimation of heritability and genetic correlations for the major fatty acids in bovine milk.
      , and genotype (
      • Coleman J.
      • Pierce K.M.
      • Berry D.P.
      • Brennan A.
      • Horan B.
      Increasing milk solids production across lactation through genetic selection and intensive pasture-based feed system.
      can all be reflected in milk fat percentage. One result of inadequate descriptions of experimental trials is that conclusions from these studies need to be interpreted cautiously. Table 5 compiles several studies in which organic and conventionally produced milks have been compared concerning their fat, protein, and lactose contents and lists the reported causes, as proposed by the authors, for any differences.
      Table 5Differences in milk composition between organic and conventional produced milk
      Milk compoundReferenceReported causes for differences in composition

      between organic and conventional milk
      Fat %
       Increased in organic

      Zagorska, J., and I. Ciprovica. 2008. The chemical composition of organic and conventional milk in Latvia. Proc. 3rd Baltic Conference on Food Science and Technology. (FOODBALT-2008). Latvia University of Agriculture Faculty of Food Technology. 10–14.

      No comment on breed or diet specifics
      • Anacker G.
      Differences between composition of organic milk and conventional milk.
      No comment on breed or diet specifics; higher amount of green fodder in the diet and use of clover silage in winter for organic herd
      • Butler G.
      • Nielsen J.H.
      • Larsen M.K.
      • Rehberger B.
      • Stergiadis S.
      • Canever A.
      • Leifert C.
      The effects of dairy management and processing on quality characteristics of milk and dairy products.
      Differences in diet but no specifics
      Retail milk.
       Increased in conventional
      • Hanus O.
      • Brychtova J.
      • Gencurova V.
      • Pesl J.
      • Hulova I.
      • Vyletelova M.
      • Jedelska R.
      • Kopecky J.
      Effect of conversion from conventional to organic dairy farm on milk quality and health of dairy cows.
      Diet differences, all-year-round TMR for conventional cows, pasture grazing for organic cows during summer
      • Sundberg T.
      • Berglund B.
      • Rydhmer L.
      • Strandberg E.
      Fertility, somatic cell count and milk production in Swedish organic and conventional dairy herds.
      Preference for non-Holstein and mixed breeds in organic herds, lower replacement rates in organic herds
      • Kuczyńska B.
      • Puppel K.
      • Gołȩbiewski M.
      • Metera E.
      • Sakowski T.
      • Słoniewski K.
      Differences in whey protein content between cow's milk collected in late pasture and early indoor feeding season from conventional and organic farms in Poland.
      Higher fiber intake
       NS
      • Vicini J.
      • Etherton T.
      • Kris-Etherton P.
      • Ballam J.
      • Denham S.
      • Staub R.
      • Goldstein D.
      • Cady R.
      • McGrath M.
      • Lucy M.
      Survey of retail milk composition as affected by label claims regarding farm-management practices.
      No comment on breed or diet specifics
      • Müller U.
      • Sauerwein H.
      A comparison of somatic cell count between organic and conventional dairy cow herds in West Germany stressing dry period related changes.
      No comment on breed or diet specifics
      • Nauta W.J.
      • Veerkamp R.F.
      • Brascamp E.W.
      • Bovenhuis H.
      Genotype by environment interaction for milk production traits between organic and conventional dairy cattle production in The Netherlands.
      No comment on breed or diet specifics
      Data from 188 organic and 152 conventional dairy farms in the Netherlands collected between 1990 and 2004.
      Protein %
       Increased in organic
      • Vicini J.
      • Etherton T.
      • Kris-Etherton P.
      • Ballam J.
      • Denham S.
      • Staub R.
      • Goldstein D.
      • Cady R.
      • McGrath M.
      • Lucy M.
      Survey of retail milk composition as affected by label claims regarding farm-management practices.
      No comment on breed or diet specifics
       Increased in conventional
      • Bilik K.
      • Lopuszanska-Rusek M.
      Effect of organic and conventional feeding of Red-and-White cows on productivity and milk composition.
      Better energy balance in conventional cows, different fermentation processes in rumen
      • Kuczyńska B.
      • Puppel K.
      • Gołȩbiewski M.
      • Metera E.
      • Sakowski T.
      • Słoniewski K.
      Differences in whey protein content between cow's milk collected in late pasture and early indoor feeding season from conventional and organic farms in Poland.
      Sugar-rich juicy feed for conventional cows, which stimulates production of butyric acid used for protein synthesis
      During late pasture season.
      • Anacker G.
      Differences between composition of organic milk and conventional milk.
      No comment on breed or diet specifics, higher amount of green fodder in the diet and use of clover silage in winter for organic herd
      • Hanus O.
      • Brychtova J.
      • Gencurova V.
      • Pesl J.
      • Hulova I.
      • Vyletelova M.
      • Jedelska R.
      • Kopecky J.
      Effect of conversion from conventional to organic dairy farm on milk quality and health of dairy cows.
      Diet differences, all-year-round TMR for conventional, pasture grazing for organic during summer, energy and protein deficiency in organic herd
      • Sundberg T.
      • Rydhmer L.
      • Fikse W.F.
      • Berglund B.
      • Strandberg E.
      Genotype by environment interaction of Swedish dairy cows in organic and conventional production systems.
      Preference for non-Holstein and mixed breeds in organic, lower replacement rates in organic herds. The interaction between system and breed was found to significantly affect all milk yield traits. Lower energy density in organic rations caused by limited concentrate content
      • Müller U.
      • Sauerwein H.
      A comparison of somatic cell count between organic and conventional dairy cow herds in West Germany stressing dry period related changes.
      No comment on breed or diet specifics
      Data from 35 organic and 33 conventional dairy farms from North Rhine–Westphalia in West Germany collected between 2002 and 2004.
       NS
      • Butler G.
      • Nielsen J.H.
      • Larsen M.K.
      • Rehberger B.
      • Stergiadis S.
      • Canever A.
      • Leifert C.
      The effects of dairy management and processing on quality characteristics of milk and dairy products.