title: Abomasal infusion of butterfat increases milk fat in lactating dairy cows.
abstract: The objective of this study was to compare the effects of abomasal infusion of butterfat containing all fatty acids (FA) present in milk, including the short- and medium-chain FA, with infusion of only the long-chain FA (LCFA) present in milk, on the FA composition and milk fat yield in lactating dairy cows. Eight rumen-fistulated Holstein cows, in early lactation (49 +/- 20 days in milk) were used in a replicated 4 x 4 Latin square design. Treatments were abomasal infusion of the following: 1) no infusion (control), 2) 400 g/d of butterfat (butterfat), 3) 245 g/d of LCFA (blend of 59% cocoa butter, 36% olive oil, and 5% palm oil) providing 50% of the 16:0 and equivalent amounts of C18 FA as found in 400 g of butterfat, and 4) 100 g/d of conjugated linoleic acid (CLA, negative control), providing 10 g of trans-10, cis-12 CLA. Fat supplements were infused in equal portions 3 times daily at 0800, 1400, and 1800 h during the last 2 wk of each 3-wk experimental period. Daily dry matter intake and milk production were unaffected by the infusion treatments. Butterfat infusion increased milk fat percentage by 14% to 4.26% and milk fat yield by 21% to 1,421 g/d compared with controls (3.74% and 1,178 g/d). Milk fat percentage and fat yield were decreased by 43% by CLA. Milk protein percentage was higher (3.70%) in CLA-infused cows than in control (3.30%), butterfat (3.28%), or LCFA (3.27%) treatments. Although LCFA had no effect on fat synthesis, abomasal infusion of butterfat increased milk fat percentage and yield, suggesting that the availability of short- and medium-chain FA may be a limiting factor for milk fat synthesis.
authors.affiliation: Animal and Avian Sciences Department, University of Maryland, College Park 20742, USA.
authors.forename: A K G
authors.initials: AK
authors.lastname: Kadegowda
authors.forename: L S
authors.initials: LS
authors.lastname: Piperova
authors.forename: P
authors.initials: P
authors.lastname: Delmonte
authors.forename: R A
authors.initials: RA
authors.lastname: Erdman
mesh_terms: D000018:Abomasum / Q000378:metabolism*; D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001682:Biological Availability; D002417:Cattle / Q000378:metabolism*; D018592:Cross-Over Studies; D004041:Dietary Fats / Q000378:metabolism / Q000493:pharmacokinetics*; D005260:Female; D007263:Infusions, Parenteral / Q000662:veterinary; D007774:Lactation / Q000378:metabolism*; D008055:Lipids / Q000096:biosynthesis; D008892:Milk / Q000737:chemistry* / Q000378:metabolism*; D011897:Random Allocation
chemical_list: D004041:Dietary Fats; D008055:Lipids