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Article: Portal Drained Visceral Flux, Hepatic Metabolism, and Mammary Uptake of Free and Peptide-Bound Amino Acids and Milk Amino Acid Output in Dairy Cows Fed Diets Containing Corn Grain Steam Flaked at 360 or Steam Rolled at 490 g/L
- Article from:
- Journal of Dairy Science
- Article date:
- February 1, 2004
- Author:
CopyrightCopyright American Dairy Science Association Feb 2004. Provided by ProQuest LLC. (Hide copyright information)
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ABSTRACT
Objectives were to measure net fluxes of free (FAA) and peptide bound amino acids (AA) (PBAA) across portal-drained viscera (PDV), liver, splanchnic, and mammary tissues, and of milk AA output of lactating Holstein cows (n = 6, 109 ± 9 d in milk) as influenced by flaking density of corn grain. Cows were fed alfalfabased total mixed ration (TMR) containing 40% steamflaked (SFC) or steam-rolled corn (SRC) grain. The TMR were offered at 12-h intervals in a crossover design. Six sets of blood samples were obtained from indwelling catheters in portal, hepatic, and mammary veins and mesenteric or costoabdominal arteries every 2 h from each cow and diet. Intake of dry matter (18.4 ± 0.4 ...