The variation throughout a year in the fatty acid composition of milk fat from 2 dairy herds

Hutton, K; Seeley, Robert C.; Armstrong, David G.

doi:10.1017/s0022029900012589

Cited by 18 publications

(6 citation statements)

References 11 publications

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“…Our findings are not consistent with those of previous experiments in dairy cows. Indeed, an increase in the proportion of long-chain fatty acids in cow milk and colostrum during warm months has been observed by others (Gallacier et al 1974 ;Palmquist et al 1993 ;Nardone et al 1997), which has been ascribed either to dietary effects (Jensen & Clark, 1988), namely the transition from dry forages to fresh pasture grasses (Christie, 1980), or to reduced synthesis of 4 : 0-14 : 0 fatty acids in the mammary gland (Hutton et al 1969), owing to reduced feed intake and subsequent lower production of short-chain fatty acid precursors in the rumen (Smith et al 1983 ;Bernabucci & Calamari, 1998). However, dietary effects on milk lipid composition were excluded in this experiment, because all groups were offered the same ration and had similar feed intakes.…”

Section: mentioning

confidence: 88%

Fatty acid composition of ewe milk as affected by solar radiation and high ambient temperature

Sevi

Rotunno

Caterina

et al. 2002

Journal of Dairy Research

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Forty lactating Comisana ewes were either exposed to or protected from solar radiation and fed either in the morning or afternoon during summer in a Mediterranean climate. Individual milk samples were taken on days 7, 21 and 42 of the study period to determine fatty acid composition by gas chromatography. Exposure to solar radiation resulted in higher proportions of short-chain and saturated fatty acids in milk, primarily because of increased contents of caproic, capric, lauric, myristic and stearic acids (by 3–18%), and decreased contents of oleic, linoleic and linolenic acids (by 2–9%). As a consequence, the long to short chain and the unsaturated to saturated fatty acid ratios were significantly higher by 4 and 13% respectively in the milk of the protected ewes compared with that of the exposed animals. Provision of shade also led to an increase in the 18[ratio ]0+18[ratio ]1 to 16[ratio ]0 ratio, and to a decrease in the 12[ratio ]0+14[ratio ]0+16[ratio ]0 fatty acid group, which are regarded as reliable indexes of the nutritional property of dietary fat in reducing cholesterol levels in human plasma. Feeding time had little impact on milk fat. Our findings suggest that high ambient temperature may markedly modify the lipid composition of ewe milk and that provision of shade, but not feeding management, can improve the milk fatty acid profile in dairy sheep raised in hot climates.

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Section: mentioning

confidence: 88%

Fatty acid composition of ewe milk as affected by solar radiation and high ambient temperature

Sevi

Rotunno

Caterina

et al. 2002

Journal of Dairy Research

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“…C18 acids in milk fat result mainly from dietary intake of ALA and LA from green pasture abundant in the grass growing season . Palmitic acid in milk fat is both synthesized de novo in mammary tissue and obtained from blood triacylglycerols.…”

Section: Fatty Acids In Milkmentioning

confidence: 99%

Grazing increases the unsaturated fatty acid concentration of milk from grass‐fed cows: A review of the contributing factors, challenges and future perspectives

Elgersma

2015

Euro J Lipid Sci & Tech

137

129

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Grazing animals walk outdoors and harvest fresh herbage from a three‐dimensional canopy. Botanical composition and grassland management in various farming systems affect herbage intake and milk fatty acid (FA) composition. Grazing animals encounter a vertical gradient while grazing down a sward; responses in milk FA composition are discussed. Grazing animals have diets rich in poly‐unsaturated fatty acids (PUFA), particularly α‐linolenic acid (C18:3n‐3). Concentrates and starch‐rich fodders affect rumen retention time of the feed, increase linoleic acid (C18:2n‐6) intake, and alter biohydrogenation pathways toward less n‐3 PUFA and less rumenic acid (conjugated linoleic acid (CLA) isomer C18:2c9t11), leading to lower contents of these compounds in the milk. Milk from grazing‐based production systems including organic systems, therefore, has less saturated and more n‐3PUFA and CLAc9t11 which is considered beneficial for health. The occurrence of natural trans FA (t11) in milk predominates with grazing whereas intensive feeding practices enhance t10‐FA, with possible negative health effects. FA intake – output relations can differ among plant species due to rapid rumen passage rate or compounds protecting PUFA, resulting in more PUFA in milk. Methodological constraints for FA measurement in herbages are discussed. Trends in grazing and dairy farming systems and implications for milk FA composition are addressed. Practical applications: Grazing is important for fresh forage intake, animal health and natural behaviour, landscape values and grassland biodiversity. Grazing is a political, societal and marketing issue in The Netherlands where retailers since 2011 sell dairy products labelled as “pasture‐milk” and dairies pay a premium to farmers whose cows get access to pasture. Grazing affects green leaf intake because animals can select. Pasture allowance enhances α‐linolenic acid and CLAc9t11 (rumenic acid) concentrations in milk fat. FA need to be designated by unique names; CLA is a generic term and isomers give rise to different biological responses. As some forbs reduce biohydrogenation, grassland species diversity may improve PUFA transfer efficiency from feed to milk. Trends in animal genetics and increased herd size, TMR feeding and automated milking systems cause reduction of grazing in Europe, which can increase saturated and trans‐10 milk FA concentrations and reduce naturally occurring fat‐soluble vitamins and antioxidants in dairy products. Grazing (pasture‐feeding versus indoor with conserved forage and concentrates) increases n‐3 PUFA and trans‐11 over trans‐10 FA in cow milk when cows can select, as leaves have high n‐3 PUFA concentrations; biodiverse grasslands enhance this effect as some forbs show less PUFA rumen biohydrogenation than grasses, thus increasing efficiency of PUFA transfer from forage to milk.

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“…Detailed analyses of samples of milk fat collected from dairies or individual herds of several countries have shown characteristic changes in fatty acid composition throughout the year. Milk fat from animals fed typical winter diets of roughage and concentrates contains higher proportions of C 4 _ 16 acids and lower proportions of C 18 acids compared with milk from summer periods when the animals are fed grass diets (Patton, McCarthy, Evans & Lynn, 1960;Hawke, 1963;Boatman, Hotchkiss & Hammond, 1965;Antila, 1965;Svensen, 1967;Hutton, Seeley & Armstrong, 1969;Mattson, Swartling & Nilsson, 1969;Hall, 1970). The increased proportions of C 18 acids probably originate indirectly through hydrogenation in the rumen of increased dietary intakes of linoleic and linolenic acids on the grass diet.…”

Section: Effect Of Season and Inanition On Milk Fat Secretionmentioning

confidence: 99%

Section A. Physiology. Ruminant metabolism in relation to the synthesis and secretion of milk fat

Storry¹

1970

Journal of Dairy Research

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The variation throughout a year in the fatty acid composition of milk fat from 2 dairy herds

Cited by 18 publications

References 11 publications

Fatty acid composition of ewe milk as affected by solar radiation and high ambient temperature

Fatty acid composition of ewe milk as affected by solar radiation and high ambient temperature

Grazing increases the unsaturated fatty acid concentration of milk from grass‐fed cows: A review of the contributing factors, challenges and future perspectives

Section A. Physiology. Ruminant metabolism in relation to the synthesis and secretion of milk fat

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