Splanchnic and mammary nitrogen metabolism by dairy cows fed differently-processed sorghum and corn grain

Persistent Link:
http://hdl.handle.net/10150/282499
Title:
Splanchnic and mammary nitrogen metabolism by dairy cows fed differently-processed sorghum and corn grain
Author:
Delgado-Elorduy, Agustin 1965.
Issue Date:
1997
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Objectives were to determine net uptake or release of α-amino N (AAN), ammonia N (NH₃N) and urea N (UN) across portal-drained viscera (PDV), liver, splanchnic (PDV + liver) and mammary tissues of lactating cows fed differently processed sorghum or corn. Cows were fitted with catheters in blood vessels (artery and portal, hepatic and mammary vein), and received in a switchback design TMR containing 40% dry-rolled (DR; 643 g/L or 50 lb/bu) or steam-flaked (SF; 360 g/L or 28 lb/bu) sorghum (Exp. 1), and steam-rolled (SR; 489 g/L or 38 lb/bu) or SF corn (Exp. 2). Neither daily intake of DM and nutrients nor milk yield and efficiency of milk production were altered by feeding processed sorghum or corn. Milk fat yield was lowered (P=.03) by SF vs. DR sorghum; SF vs SR of corn tended to increase (P=.07) concentration but not yield of milk protein. Blood flows in portal (1988 ± 109 L/h) and hepatic vein (2368 ± 215 L/h) were not altered by diets. Steam-flaked vs. DR sorghum tended (P=.18) to increase UN cycling (162 vs. 95 g/d), and reduced (P≤.09) absorption of AAN (223 vs. 269 g/d) and NH3N (257 vs. 318 g/d) by PDV. Flaking vs. rolling of sorghum increased (P≤.07) estimated uptake (83 vs. 67 g/d) and extraction ratio (14.5 vs. 11.1%) of AAN by mammary tissues. Net uptake and release of AAN and NH3N across splanchnic tissues of cows were not altered by corn processing; however, SF vs. SR corn increased (P=.08) UN cycling to PDV by 143% (212 vs. 87 g/d). Steam-flaked vs SR corn increased (P≤.02) estimated uptake (88 vs. 61 g/d) and extraction ratio (14.7 vs. 11.0%) of AAN by mammary tissues. It is concluded that feeding of steam-flaked sorghum or corn compared to dry-rolled sorghum or steam-rolled corn improves N utilization of dairy cows by increasing urea transfer to the gut and uptake of amino acid by the mammary gland.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Agriculture, Animal Culture and Nutrition.; Agriculture, Animal Culture and Nutrition.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Animal Sciences
Degree Grantor:
University of Arizona
Advisor:
Theurer, C. Brent

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleSplanchnic and mammary nitrogen metabolism by dairy cows fed differently-processed sorghum and corn grainen_US
dc.creatorDelgado-Elorduy, Agustin 1965.en_US
dc.contributor.authorDelgado-Elorduy, Agustin 1965.en_US
dc.date.issued1997en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractObjectives were to determine net uptake or release of α-amino N (AAN), ammonia N (NH₃N) and urea N (UN) across portal-drained viscera (PDV), liver, splanchnic (PDV + liver) and mammary tissues of lactating cows fed differently processed sorghum or corn. Cows were fitted with catheters in blood vessels (artery and portal, hepatic and mammary vein), and received in a switchback design TMR containing 40% dry-rolled (DR; 643 g/L or 50 lb/bu) or steam-flaked (SF; 360 g/L or 28 lb/bu) sorghum (Exp. 1), and steam-rolled (SR; 489 g/L or 38 lb/bu) or SF corn (Exp. 2). Neither daily intake of DM and nutrients nor milk yield and efficiency of milk production were altered by feeding processed sorghum or corn. Milk fat yield was lowered (P=.03) by SF vs. DR sorghum; SF vs SR of corn tended to increase (P=.07) concentration but not yield of milk protein. Blood flows in portal (1988 ± 109 L/h) and hepatic vein (2368 ± 215 L/h) were not altered by diets. Steam-flaked vs. DR sorghum tended (P=.18) to increase UN cycling (162 vs. 95 g/d), and reduced (P≤.09) absorption of AAN (223 vs. 269 g/d) and NH3N (257 vs. 318 g/d) by PDV. Flaking vs. rolling of sorghum increased (P≤.07) estimated uptake (83 vs. 67 g/d) and extraction ratio (14.5 vs. 11.1%) of AAN by mammary tissues. Net uptake and release of AAN and NH3N across splanchnic tissues of cows were not altered by corn processing; however, SF vs. SR corn increased (P=.08) UN cycling to PDV by 143% (212 vs. 87 g/d). Steam-flaked vs SR corn increased (P≤.02) estimated uptake (88 vs. 61 g/d) and extraction ratio (14.7 vs. 11.0%) of AAN by mammary tissues. It is concluded that feeding of steam-flaked sorghum or corn compared to dry-rolled sorghum or steam-rolled corn improves N utilization of dairy cows by increasing urea transfer to the gut and uptake of amino acid by the mammary gland.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectAgriculture, Animal Culture and Nutrition.en_US
dc.subjectAgriculture, Animal Culture and Nutrition.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineAnimal Sciencesen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorTheurer, C. Brenten_US
dc.identifier.proquest9814385en_US
dc.identifier.bibrecord.b37741974en_US
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