title: Diet supplementation with fish oil and sunflower oil to increase conjugated linoleic acid levels in milk fat of partially grazing dairy cows.
abstract: The objective of this study was to determine the long-term effect on milk conjugated linoleic acid (cis-9, trans-11 CLA) of adding fish oil (FO) and sunflower oil (SFO) to the diets of partially grazing dairy cows. Fourteen Holstein cows were divided into 2 groups (7 cows/treatment) and fed either a control or oil-supplemented diet for 8 wk while partially grazing pasture. Cows in group 1 were fed a grain mix diet (8.0 kg/d, DM basis) containing 400 g of saturated animal fat (control). Cows in the second group were fed the same grain mix diet except the saturated animal fat was replaced with 100 g of FO and 300 g of SFO. Cows were milked twice a day and milk samples were collected weekly throughout the trial. Both groups grazed together on alfalfa-based pasture ad libitum and were fed their treatment diets after the morning and afternoon milking. Milk production (30.0 and 31.2 kg/d), milk fat percentages (3.64 and 3.50), milk fat yield (1.08 and 1.09 kg/d), milk protein percentages (2.97 and 2.88), and milk protein yield (0.99 and 0.91 kg/d) for diets 1 and 2, respectively, were not affected by the treatment diets. The concentrations of cis-9, trans-11 CLA (1.64 vs. 0.84 g/100 g of fatty acids) and vaccenic acid (5.11 vs. 2.20 g/100 g of fatty acids) in milk fat were higher for cows fed the oil-supplemented diet over the 8 wk of oil supplementation. The concentration of cis-9, trans-11 CLA in milk fat reached a maximum (1.0 and 1.64 g/100 g of fatty acids for diets 1 and 2, respectively) in wk 1 for both diets and remained relatively constant thereafter. The concentration of vaccenic acid in milk fat followed the same temporal pattern as cis-9, trans-11 CLA. In conclusion, supplementing the diet of partially grazing cows with FO and SFO increased the milk cis-9, trans-11 CLA content, and that increase remained relatively constant after 1 wk of oil supplementation.
authors.affiliation: Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale 62901, USA. aabugha@siu.edu
authors.forename: A A
authors.initials: AA
authors.lastname: AbuGhazaleh
authors.forename: L D
authors.initials: LD
authors.lastname: Holmes
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle / Q000378:metabolism / Q000502:physiology*; D004041:Dietary Fats / Q000008:administration & dosage / Q000378:metabolism; D019587:Dietary Supplements; D005260:Female; D005395:Fish Oils / Q000008:administration & dosage* / Q000378:metabolism; D007774:Lactation / Q000378:metabolism*; D044243:Linoleic Acids, Conjugated / Q000032:analysis* / Q000378:metabolism; D008892:Milk / Q000737:chemistry*; D009829:Oleic Acids / Q000008:administration & dosage / Q000378:metabolism; D010938:Plant Oils / Q000008:administration & dosage* / Q000378:metabolism; D011897:Random Allocation; D000074242:Sunflower Oil; D013997:Time Factors
chemical_list: D004041:Dietary Fats; D005395:Fish Oils; D044243:Linoleic Acids, Conjugated; D009829:Oleic Acids; D010938:Plant Oils; D000074242:Sunflower Oil; C050413:11-octadecenoic acid