title: Abomasal infusion of cis or trans fatty acid isomers and energy metabolism of lactating dairy cows.
abstract: Diets for dairy cows that provide or induce formation of trans isomers of polyunsaturated fatty acids result in reduced percentages of milk fat. The effect of abomasal infusion of trans-C18:1 fatty acid isomers on energy utilization by mature cows was determined. Six multiparous Holstein cows in midlactation had ad libitum access to a basal diet containing 50% forage and 50% concentrate. Treatments were 1) no infusion, 2) infusion of 630 g/d of a fat mixture high in cis-C18:1 isomers (64% cis-C18:1; 68% high oleic sunflower oil and 32% cocoa butter), and 3) infusion of 623 g/d of a fat mixture high in trans-C18:1 isomers (42% trans-C18:1; 90% partially hydrogenated soybean oil and 10% high linoleic safflower oil). The experiment was a replicated 3 x 3 Latin square design with 4-wk periods. Measurements of energy balance were made in open circuit respiration chambers during wk 4 of each period. Fat infusion increased milk production by 2.5 kg/d; apparent digestibility of DM, OM, energy, ADF, and ash by 1 to 4 percentage units; metabolizable energy by 11%; and NEL of the diet by 15%. Milk fat percentage and yield were higher when cows were infused with cis-C18:1 than when they were infused with trans-C18:1 (4.12% and 1.41 kg/d vs. 3.15% and 1.06 kg/d, respectively). Infusion of fat increased milk production, but trans-C18:1 reduced milk fat and energy output.
authors.affiliation: Department of Animal Science, University of Maryland, College Park 20742, USA.
authors.forename: G A
authors.initials: GA
authors.lastname: Romo
authors.forename: D P
authors.initials: DP
authors.lastname: Casper
authors.forename: R A
authors.initials: RA
authors.lastname: Erdman
authors.forename: B B
authors.initials: BB
authors.lastname: Teter
mesh_terms: D000018:Abomasum; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle; D004032:Diet; D004041:Dietary Fats / Q000008:administration & dosage; D004063:Digestion; D002149:Energy Intake; D004734:Energy Metabolism; D005227:Fatty Acids / Q000008:administration & dosage*; D005260:Female; D007774:Lactation / Q000502:physiology*; D050356:Lipid Metabolism; D008055:Lipids / Q000032:analysis; D008892:Milk / Q000737:chemistry / Q000378:metabolism; D010938:Plant Oils / Q000008:administration & dosage; D013237:Stereoisomerism; D000074242:Sunflower Oil
chemical_list: D004041:Dietary Fats; D005227:Fatty Acids; D008055:Lipids; D010938:Plant Oils; D000074242:Sunflower Oil; C052387:cocoa butter