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OCR for page R1
Ruminant
Nitrogen
Usage
Subcommittee on Nitrogen
Usage in Ruminants
Committee on An
mat Nutrition
Board on Agriculture
National Research Council
NATIONAL ACADEMY PRESS
Washington' D.C. 1985
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National Academy Press · 2101 Constitution Avenue, NW · Washington, DC 20418
NOTICE: The project that is the subject of this report was approved by the Governing Board of the National
Researeh Council, whose members are drawn from the councils of the National Aeademy of Seienees, the
National Aeademy of Engineering, and the Institute of Medieine. The members of the committee responsi-
ble for the report were chosen for their special eompetences and with regard for appropriate balance.
This report has been reviewed by a group other than the authors according to procedures approved by a
Report Review Committee consisting of members of the National Academy of Sciences, the National Acad-
emy of Engineering, and the Institute of Medieine.
The National Research Couneil was established by the National Aeademy of Sciences in 1916 to associate
the broad community of science and technology with the Academy's purposes of furthering knowledge and
of advising the federal government. The Council operates in accordance with general policies determined by
the Aeademy under the authority of its congressional charter of 1863, which establishes the Academy as a
private, nonprofit, self-governing membership corporation. The Couneil has become the principal operat-
ing agency of both the National Aeademy of Sciences and the National Aeademy of Engineering in the
conduct of their services to the government, the public, and the scientific and engineering communities. It is
administered jointly by both Academies and the Institute of Medicine. The National Aeademy of Engineer-
ing and the Institute of Medieine were established in 1964 and 1970, respectively, under the charter of the
National Academy of Sciences.
This study was supported by the Agricultural Researeh Service of the U.S. Department of Agriculture, by
the Center for Veterinary Medicine, Food and Drug Administration of the U.S. Department of Health and
Human Services, and by the American Feed Industry Association, Ine.
Library of Congress Cataloging in Publication Data
National Researeh Couneil (U.S.) Subcommittee on
Nitrogen Usage in Ruminants.
Ruminant nitrogen usage.
Bibliography: p.
Includes index.
1. Nitrogen in animal nutrition. 2. Ruminants-
Feeding and feeds. I. Title.
SF98.NSN37 1985 636.2'08'52 85-21682
ISBN 0-309-03597-X
Copyright (D 1985 by the National Academy of Sciences
No part of this book may be reproduced by any mechanical, photographic, or electronic process, or in the
form of a phonographic recording, nor may it be stored in a retrieval system, transmitted, or otherwise
copied for public or private use, without written permission from the publisher, except for purposes of offi-
cial use by the United States government.
First Pnnung, October 1985
Second Panting, December 1991
Printed in the United States of America
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Preface
The Subcommittee on Nitrogen Usage in Ruminants
of the Committee on Animal Nutrition was instructed to
address the increasingly apparent need to bring together
the newer data and knowledge on ruminant nitrogen
metabolism in such a way that a systematic, quantita-
tive approach to the rationing of ruminants for nitrogen
could be set forth.
The charge to the Subcommittee included the need to
produce a report that could be used by producers, tech-
nical service people in the feed ant] related industries, as
well as extension personnel, teachers, students, and
research scientists. The document was to serve as a base,
upon which future refinement could be built, in such a
way that continual improvement would occur.
Whereas many countries around the world have pro-
posed nitrogen or protein systems for ruminants, this ef-
fort was to evaluate each of those and incorporate those
biological principles that are common to all ruminants.
During the course of the Liberations of this subcom-
mittee, invaluable help has been provided by the staff of
the Board on Agriculture, especially Selma P. Baron and
Philip Ross. This has been a most complex task, and
without the encouragement and assistance of these peo-
ple, the document contained herein would not have
emerged.
We especially appreciate the efforts of Werner G.
Bergen who reviewed this report for the Committee on
Animal Nutrition and provided useful information for
consideration by the authoring subcommittee. Also, the
encouragement of Joseph P. Fontenot and Robert R.
Oltjen has been greatly appreciated; the former also
served as the reviewer for the Board on Agriculture. As a
result, we fee! that we have produced a document that
meets the stated objectives of the original charge. The
assistance of Zaira Batchelder, Alice Jones, and Elaine
Wylie in the preparation of drafts and manuscripts is
gratefully acknowledged.
Subcommittee on Nitrogen Usage in Ruminants
LEONARD S. BULL, Chairman
University of Vermont
WILLIAM CHALUPA
University of Pennsylvania
FREDRIC N. OWENS
Oklahoma State University
LARRY D. SATTER
USDA, Dairy Forage Research Center
CHARLES J. SNIFFEN
Cornell University
ALLEN H. TRENKLE
Iowa State University
DALE R. WALDO
USDA, Agricultural Research Service
· - ~
111
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COMMITTEE ON ANIMAL NUTRITION
DUANE E. ULLREY, Chairman, Michigan State
University
FRANK AHERNE, University of Alberta
RICHARD E. AUSTIC, Cornell (Jniversity
JIMMY H. CLARK, University of Illinois
RICHARD D. GOODRICH, University of Minnesota
GEORGE E. MITCHELL, JR., University of
Kentucky
JAMES G. MORRIS, University of California-Davis
ROBERT R. SMITH, USDI, Fish and Wildlife Service
DALE R. WALDO, USDA, Agricultural Research
~ .
service
SELMA P. BARON, Staff Officer
BOARD ON AGRICULTURE
WILLIAM L. BROWN, Pioneer Hi-Bred
International, Inc., Chairman
JOHN A. PING, Inter-American Development Bank,
Vice Chairman
PERRY L. ADKISSON, Texas A&M University
C. EUGENE ALLEN, University of Minnesota
LAWRENCE BOGORAD, Harvard University
ERIC L. ELLWOOD, North Carolina State University
JOSEPH P. FONTENOT, Virginia Polytechnic
Institute and State University
RALPH W. F. HARDY, Cornell University and
BioTechnica International, Inc.
ROGER L. MITCHELL, University of Missouri
CHARLES C. MUSCOPLAT, Molecular Genetics,
Inc.
ELDOR A. PAUL, University of California-Berkeley
VERNON W. RUTTAN, University of Minnesota
JAMES G. TEER, Welder Wildlife Foundation
JAN VAN SCHILFGAARDE, USDA, Agricultural
Research Service
VIRGINIA WALBOT, Stanford University
CHARLES M. BENBROOK, Executive Director
1V
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Contents
Introduction
Parameter Names for Describing
Protein Metabolism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
.
Comparison of New Protein Systems
for Ruminants
Feed Evaluation
7
.23
Degradation of Dietary Crude Protein
in the Reticulo-Rumen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Microbial Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
Digestion and Absorotion in the
Small Intestine
~-
46
Nitrogen Metabolism in the
Large Intestine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
Nitrogen Metabolism in Tissues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Application to Ruminant Feeding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ~
Appendix Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87
Index
v
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Figures, Tables, and
Appendix Tables
FIGURES
1. Schematic of nitrogen flow in the ruminant, 2
2. Schematic diagram of nitrogen flow in the ruminant using symbols developed in this
publication, 3
3. Intake protein percentage in dry matter as a function of milk production, 17
4. Undegradability of dietary intake protein as a function of milk production, 18
5. Undegradability of dietary intake protein as a function of intake protein percentage in dry
matter, 18
6. Protein flow into small intestine predicted from the system versus that expected based on
the digestible organic matter of the system and the equation of Tamminga and van
Hellemond (1977), 19
7. Protein flow into small intestine predicted from the system versus that expected based on
the digestible organic matter of the system and the equation of Rohr et al. (1979), etc., 19
8. Protein flow into small intestine predicted from the system versus that expected based on
the digestible organic matter plus undegraded protein intake of the system and the equation
of Journet and V`erite (1979), 20
9. Fecal protein as a function of intake protein percentage in dry matter, 20
10. Fecal protein as a function of milk production, 21
11. Urinary protein as a function of milk production, 21
12. Milk protein as a function of milk production, 22
13. Simplified model showing flow of amino acids in mammalian metabolism, 58
TABLES
1. Assumed Factors in the Availability of Absorbed Protein to Ruminants, 9
2. Assumed Factors in the Requirement of Absorbed Protein by Ruminants for Maintenance,
Milk Production, and Body Weight Change, 10
3. Dry Matter Intakes and Energy Standards When Energy Concentration Varied as Used in
Comparison and Challenge of Protein Systems, 16
4. Additional Assumptions of Protein and Energy Relationships, 17
5. Interrelationship Among In Vivo Responses, Undegradability Assays, and Insolubility
Assays, 24
6. Tentative Estimates of Undegraded Protein for Common Feedstuffs When Total Dry
Matter Intake is in Excess of 2 Percent of Body Weight, 33
7. Composition of Microbial Cells, 38
8. Regressions for Dairy Cattle, Sheep, and Beef Cattle, 42
Vl
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Figures, Tables, and Appendix Tables vii
9. Empirical Prediction Models of Microbial Nitrogen Flow, 44
10. Equations Used for Predicting Microbial Yield or Efficiency, 45
11. Summary of Apparent Absorption of Nonammonia Nitrogen ant] Amino Acids from the
Small Intestine of Ruminants, 47
12. Proportionate Disappearance of Amino Acids from the Small Intestine, 48
13. Supplies of Nonammonia Nitrogen and Amino Acids to the Proximal Duodenum and Ter-
minal Ileum, Apparent and True Digestibility of Nitrogen, and Endogenous Loss of Nitro-
gen to the Small Intestine, 49
14. Summary of True Absorption from the Small Intestine, 50
15. Estimates of True Digestibility and Metabolic Fecal Nitrogen, 54
16. Extraction of Amino Acids by Various Tissues, 58
17. Estimated New Protein Requirements for Growth of Cattle of Different Body Weights and
Gaining at Different Rates, 64
18. Protein Retention in Gain of Growing Sheep, 64
19. Protein Retention in Fetus and Gravid Uterus of Cattle at Different Stages of Gestation, 64
20. Protein Retention in Fetus and Gravid Uterus of Sheep at Different Stages of Gestation, 65
21. Protein Content of Milk, 65
APPENDIX TABLES
1. Numerical Data from the Protein Systems Used in Figures 3 Through 12, 89
2. In Vivo Estimates of the Percentage of Undegraded Protein in Common Feedstuffs, 90
3. Microbial Flow and Rumen Organic Matter Digestion, 98
4. Urea Usefulness with Various Feed Intakes, TDN Levels, and Ruminal Digestions of
Dietary Protein Based on Equations from Dairy Cattle, 108
5. Urea Usefulness with Various Feed Intakes, TDN Levels, and Ruminal Digestions of
Dietary Protein Based on Equations from Beef Cattle, 109
6 Urea Usefulness with Various Feed Intakes, TDN Levels, and Ruminal Digestions of
Dietary Protein Based on Equations from Sheep, 109
7. Production of Microbial Protein and Escape Protein Requirements for Beef Cattle of
Various Weights and Types, 110
8. Requirements of Total and Escape Protein for Beef Cattle of Various Types, Weights, and
Rates of Gain, 111
9. Factors Adopted for Transforming Feed Protein into Net Protein for Dairy Cattle, 113
10. Factors Adopted for Transforming Feed Protein into Net Protein for Beef Cattle, 123
11. Apparent Absorption of Nitrogen from the Small Intestine of Lactating Cattle, 135
12. Apparent Absorption of Nitrogen from the Small Intestine of Nonlactating Cattle, 135
13. Apparent Absorption of Nitrogen from the Small Intestine of Sheep, 136
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Ruminant
Nitrogen
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