Ruminal nitrogen metabolism in steers as affected by feed intake and dietary urea concentration.
J Dairy Sci
; 70(11): 2302-11, 1987 Nov.
Article
en En
| MEDLINE
| ID: mdl-3693634
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 15N-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 15N was similar between bacteria among treatments and was 30% lower for protozoa. Turnover rates of 15N in bacteria, NH3N, and non-NH3N 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.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Rumen
/
Urea
/
Bovinos
/
Alimentación Animal
/
Nitrógeno
Límite:
Animals
Idioma:
En
Revista:
J Dairy Sci
Año:
1987
Tipo del documento:
Article
Pais de publicación:
Estados Unidos