J. Anim Sci.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Smith, S. B.
Right arrow Articles by Mersmann, H. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Smith, S. B.
Right arrow Articles by Mersmann, H. J.

Journal of Animal Science, Vol 70, Issue 1 152-160, Copyright © 1992 by American Society of Animal Science

JOURNAL ARTICLE

Nitrogen and lipid metabolism in heifers fed at increasing levels of intake

S. B. Smith, R. L. Prior, L. J. Koong and H. J. Mersmann
Department of Animal Science, Texas A&M University, College Station 77843-2471.

The relationship between N and lipid metabolism was investigated in heifers fed five different levels of feed intake (five heifers per treatment group). Targeted ME intakes were 84, 123, 157, 191, and 225 kcal per kt.75 per day, which were .76x, 1.12x, 1.43x, 1.74x, and 2.05x (times) the estimated ME requirement for maintenance. After 120 d on trial, the heifers were moved to a confinement building for 7 d, and feces and urine were collected over a 3-d period. On the 1st d of confinement, blood samples were collected every 15 min for a total of 15 samples. Because the group fed at 1.43x maintenance was fed improperly during the period in confinement, this group was omitted from the study. Adipose tissue samples were obtained at slaughter to obtain in vitro measures of lipid metabolism. As feed intake increased, N retention increased (P less than .05) from 1.7 to 24.3 g/d. Daily urinary N tau-methylhistidine excretion was significantly different between the .76x and 1.74x treatments (769 vs 1,575 mumol/d, respectively). The fractional breakdown rate of myofibrillar proteins also was significantly different between these two groups of heifers (1.49 vs 2.44%/d, respectively). Plasma glucose and insulin were lowest (P less than .05) at the lowest level of feed intake. Conversely, plasma nonesterified fatty acids were lowest (P less than .05) in those animals receiving the highest level of feed intake. Subcutaneous adipocytes were smallest (93 microns) in the heifers fed at 33% ad libitum intake and largest in heifers fed at 76 or 90% ad libitum intake (115 and 110 microns, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)


This article has been cited by other articles:


Home page
 J ANIM SCIHome page
S. B. Smith, A. A. Chapman, D. K. Lunt, J. J. Harris, and J. W. Savell
Adiposity of calf- and yearling-fed Brangus steers raised to constant-age and constant-body weight endpoints
J Anim Sci, May 1, 2007; 85(5): 1136 - 1143.
[Abstract] [Full Text] [PDF]

Home page
 J ANIM SCIHome page
L. Majdoub, M. Vermorel, and I. Ortigues-Marty
Ryegrass-based diet and barley supplementation: Partition of energy-yielding nutrients among splanchnic tissues and hind limbs in finishing lambs
J Anim Sci, April 1, 2003; 81(4): 1068 - 1079.
[Abstract] [Full Text] [PDF]

Home page
 J. Nutr.Home page
W. J. J. Gerrits, J. Dijkstra, and J. France
Description of a Model Integrating Protein and Energy Metabolism in Preruminant Calves
J. Nutr., June 1, 1997; 127(6): 1229 - 1242.
[Abstract] [Full Text]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1992 by the American Society of Animal Science.