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United States Department of Agriculture

Agricultural Research Service

Title: Frequency of Protein Supplementation on Net Portal and Hepatic Flux of Nutrients in Mature Ewes Consuming Low Quality Forage

Authors
item Krehbiel, Clinton
item Ferrell, Calvin
item FREETLY, HARVEY

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: June 24, 1996
Publication Date: N/A

Technical Abstract: The objective was to determine net portal-drained viscera (PDV) and hepatic flux of nutrients when ewes consuming low-quality forage were supplemented with protein at 0, 24, or 72-h intervals. Six Polled Dorset ewes (37 ñ 4 kg) fitted with hepatic venous, hepatic portal, abdominal aorta, and mesenteric venous catheters were used in a replicated 3 x 3 Latin square design. Ewes were offered brome hay (7.7% CP) ad libitum. Treatments were no soybean meal (SBM; control), SBM fed once every 24 h, or SBM fed once every 72 h. Soybean meal was fed in amounts to provide 80 g/d of CP. Blood flow and net flux measurements were made 3 d of each period so that ewes supplemented on a 72-h interval were sampled the day of, the day after, and 2 d after supplementation. Arterial concentrations of alpha-amino N (AAN) and ammonia N were lower (P < .05) when SBM was fed, whereas arterial concentrations of urea N and oxygen were greater (P < .05). When SBM was fed, net PDV absorption of AAN, ammonia N, and oxygen consumption were greater (P < .05) than in control ewes. Net PDV removal of urea N was not affected (P > .10) by treatment. A SBM day interaction (P < .05) occurred as net PDV absorption of AAN and ammonia N were greater the day after supplementation than the day of or 2-d after in ewes fed SBM on a 72-h interval. Net hepatic removal of AAN, ammonia N, and oxygen, and net hepatic release of urea N were greater (P < .06) in ewes fed SBM compared with control ewes. Interval of protein supplementation may affect the pattern of absorption but does not affect net absorption of nitrogenous compounds.

Last Modified: 7/25/2014
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