title: Digestive and metabolic utilization of lauric, myristic and stearic acid in cows, and associated effects on milk fat quality.
abstract: In an experiment with 3 x 6 Brown Swiss cows, the effects of dietary supplementations (40 g/kg) of non-esterified lauric (12 : 0), myristic (14 : 0) and stearic acid (18 : 0) on digestibility, metabolisability, milk fat composition and melting properties were investigated. The diet consisted of forage and concentrate in a ratio of 3 : 2. Cows were fed the C18 : 0 supplemented diet for 10 days before treatment feeding started for a 15-day experimental period where, at the end, excreta were quantitatively collected and gaseous exchange was measured. The DM intake averaged 17.9 kg/d for the C14 : 0 and C18 : 0 diets and was reduced (P < 0.05) by 18% in the C12 : 0 diet. The realised intakes of total C12 : 0, C14 :0 and C18 : 0 amounted to 368, 391 and 617 g/d in the respective groups. The efficiency of ME utilization for lactation was higher (P < 0.001) in the C12 : 0 group than in the two other groups indicating differences in metabolism of C12 : 0 in comparison with C14 : 0 and C18 : 0. Shifts in dietary fatty acid supplementation were clearly reflected in the milk fat composition. Associated changes were elevated CLA and C18 : 1 trans when supplementing C12 : 0, and a high C18 : 1 to C16 : 0 ratio (P < 0.05) in the C12 : 0and C18 : 0 groups which resulted in an easier melting milk fat than with supplementary C14 : 0. Despite certain favourable effects of C12 : 0 in metabolic energy utilization and milk fat melting properties (relative to C14 : 0), more research is needed on how to improve its palatability for dairy cows.
authors.affiliation: Institute of Animal Science, Animal Nutrition, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland.
authors.forename: Frigga
authors.initials: F
authors.lastname: Dohme
authors.forename: Andrea
authors.initials: A
authors.lastname: Machmüller
authors.forename: F
authors.initials: F
authors.lastname: Sutter
authors.forename: M
authors.initials: M
authors.lastname: Kreuzer
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle / Q000378:metabolism* / Q000502:physiology; D019587:Dietary Supplements; D004063:Digestion; D005223:Fats / Q000032:analysis*; D005260:Female; D007774:Lactation / Q000378:metabolism; D007850:Lauric Acids / Q000008:administration & dosage / Q000378:metabolism*; D008892:Milk / Q000737:chemistry / Q000592:standards*; D019814:Myristic Acid / Q000008:administration & dosage / Q000378:metabolism*; D011897:Random Allocation; D013229:Stearic Acids / Q000008:administration & dosage / Q000378:metabolism*
chemical_list: D005223:Fats; D007850:Lauric Acids; D013229:Stearic Acids; D019814:Myristic Acid; C030358:lauric acid; C031183:stearic acid