Ruminal nitrogen metabolism in steers as affected by feed intake and dietary urea concentration
Four multiple-cannulated steers (340 kg) were used in a 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments. Steers were fed a diet of 50% ground hay and 50% concentrate at two intakes (1.4 and 2.1% of BW), with urea and /sup 15/N-enriched ammonium sulfate infused continuously into the rumen at .4 or 1.2% of diet DM. Ratios of purines and diaminopimelic acid-N to N in fluid-associated and particulate-associated bacteria and in protozoa were similar among treatments but were lower for protozoa than for bacteria. Diaminopimelic acid-N:N was higher for fluid-associated vs. particulate-associated bacteria. Enrichment of /sup 15/N was similar between bacteria among treatments and was 30% lower for protozoa. Turnover rates of /sup 15/N in bacteria, NH/sub 3/N, and non-HN/sub 3/N pools were faster for steers infused with 1.2 than those infused with .4% urea, indicating less efficient usage of ammonia with higher urea. A method is described to estimate the proportion of duodenal nitrogen comprising bacterial and protozoal nitrogen.
- Research Organization:
- Univ. of Illinois, Urbana
- OSTI ID:
- 5341178
- Journal Information:
- J. Dairy Sci.; (United States), Journal Name: J. Dairy Sci.; (United States) Vol. 70:11; ISSN JDSCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
553005 -- Agriculture & Food Technology-- Animal Husbandry-- (1987-)
560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
60 APPLIED LIFE SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AMIDES
ANIMALS
BACTERIA
CARBONIC ACID DERIVATIVES
CATTLE
DIET
DOMESTIC ANIMALS
ELEMENTS
INTAKE
INVERTEBRATES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MAMMALS
METABOLISM
MICROORGANISMS
NITROGEN
NITROGEN 15
NITROGEN ISOTOPES
NONMETALS
NUCLEI
NUTRITION
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PROTOZOA
RUMINANTS
STABLE ISOTOPES
TRACER TECHNIQUES
UREA
VERTEBRATES