title: Improving the fatty acid profile of dairy cow milk by combining grazing with feeding of total mixed ration.
abstract: Grazing cows could produce milk with a higher proportion of polyunsaturated fatty acids, which is beneficial to human health, compared with non-grazing cows, though grazing alone could compromise milk production. Under oceanic climate conditions, a study involving 15 dairy cows, fed total mixed ration (TMR) ad libitum in combination with different grazing times of 12 h (TMR12), 6 h (TMR06) and zero grazing time (TMR00) with the aim to evaluate different strategies on the fatty acids profile of milk and milk production. No differences were seen between the treatments with respect to milk yield (34.4+/-6.3 kg/d) or milk protein content (30.4+/-1.8 g/kg). The milk produced by the TMR12 cows had less total fat (36.2 vs. 38.2 g/kg) and saturated fatty acid (FA, 69.39 vs. 71.44 g/100 g FA) than that produced by the TMR00 cows. The concentration of vaccenic acid in the TMR06 and TMR12 milk was twice that of the TMR00 milk (4.22, 4.09 and 2.26 g/100 g FA respectively). Linear increases in conjugated linoleic (CLA) and linolenic acids were observed with increasing grazing time. Pasture was an important source of FA especially C18:3 for TMR06 and TMR12 cows. Under oceanic climatic conditions, the grazing of dairy cows as a complement to feeding with TMR can improve the FA profile of milk and increase its CLA content.
authors.affiliation: Regional Institute for Agro-Food Research and Development (SERIDA), E-33300, Villaviciosa (Asturias), Spain.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Morales-Almaráz
authors.forename: Ana
authors.initials: A
authors.lastname: Soldado
authors.forename: Amelia
authors.initials: A
authors.lastname: González
authors.forename: Adela
authors.initials: A
authors.lastname: Martínez-Fernández
authors.forename: Ignacio
authors.initials: I
authors.lastname: Domínguez-Vara
authors.forename: Begoña
authors.initials: B
authors.lastname: de la Roza-Delgado
authors.forename: Fernando
authors.initials: F
authors.lastname: Vicente
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle; D002980:Climate; D003612:Dairying; D005223:Fats / Q000032:analysis*; D005247:Feeding Behavior; D005260:Female; D007774:Lactation / Q000378:metabolism*; D044243:Linoleic Acids, Conjugated / Q000032:analysis*; D008892:Milk / Q000737:chemistry / Q000378:metabolism; D008894:Milk Proteins / Q000032:analysis*; D009829:Oleic Acids / Q000032:analysis*; D013997:Time Factors; D017962:alpha-Linolenic Acid / Q000032:analysis*
chemical_list: D005223:Fats; D044243:Linoleic Acids, Conjugated; D008894:Milk Proteins; D009829:Oleic Acids; D017962:alpha-Linolenic Acid; C050413:11-octadecenoic acid