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Title: Effects of feed intake and dietary urea concentration on ruminal dilution rate and efficiency of bacteria growth in steers

Abstract

Four multiple-fistulated steers (340 kg) were fed a diet containing 50% ground grass hay, 20% dry distillers grains, and 30% concentrate at two intakes (7.2 or 4.8 kg DM/d). Urea (.4 or 1.2% of the diet) was infused continuously into the steers' rumens. The experimental design was a 4 x 4 Latin square with a 2 x 2 factorial arrangement of treatments. Infusing urea at .4 or 1.2% of the diet resulted in ruminal NH/sub 3/ N concentration of 4.97 and 9.10 mg/dl, respectively. Feeding steers at high rather than low intake decreased ruminal and total tract digestibilities of organic matter, NDF, and ADF but did not increase ruminal escape of N. However, apparent N escape from the rumen calculated using purines, but not /sup 15/N, as a bacterial marker was higher when 1.2 vs. .4% urea was infused. Feeding at high rather than at low intake increased the total pool of viable bacteria per gram organic matter fermented in the rumen. Although ruminal fluid outflows and particulate dilution rates were greater when steers were fed at high than low intakes, efficiencies of bacterial protein synthesis were unaffected by intake. The possibility of increased N recycling within the rumen withmore » feeding at the higher intake is discussed.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Univ. of Illinois, Urbana
OSTI Identifier:
5280746
Resource Type:
Journal Article
Journal Name:
J. Dairy Sci.; (United States)
Additional Journal Information:
Journal Volume: 70:11
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 60 APPLIED LIFE SCIENCES; BACTERIA; GROWTH; CATTLE; METABOLISM; PROTEINS; BIOSYNTHESIS; DIET; INTAKE; NITROGEN 15; TRACER TECHNIQUES; ANIMALS; DOMESTIC ANIMALS; ISOTOPE APPLICATIONS; ISOTOPES; LIGHT NUCLEI; MAMMALS; MICROORGANISMS; NITROGEN ISOTOPES; NUCLEI; ODD-EVEN NUCLEI; ORGANIC COMPOUNDS; RUMINANTS; STABLE ISOTOPES; SYNTHESIS; VERTEBRATES; 550501* - Metabolism- Tracer Techniques; 553005 - Agriculture & Food Technology- Animal Husbandry- (1987-)

Citation Formats

Firkins, J L, Lewis, S.M. Montgomery, L., Berger, L L, Merchen, N R, and Fahey, Jr, G C. Effects of feed intake and dietary urea concentration on ruminal dilution rate and efficiency of bacteria growth in steers. United States: N. p., 1987. Web. doi:10.3168/jds.S0022-0302(87)80291-6.
Firkins, J L, Lewis, S.M. Montgomery, L., Berger, L L, Merchen, N R, & Fahey, Jr, G C. Effects of feed intake and dietary urea concentration on ruminal dilution rate and efficiency of bacteria growth in steers. United States. doi:10.3168/jds.S0022-0302(87)80291-6.
Firkins, J L, Lewis, S.M. Montgomery, L., Berger, L L, Merchen, N R, and Fahey, Jr, G C. Sun . "Effects of feed intake and dietary urea concentration on ruminal dilution rate and efficiency of bacteria growth in steers". United States. doi:10.3168/jds.S0022-0302(87)80291-6.
@article{osti_5280746,
title = {Effects of feed intake and dietary urea concentration on ruminal dilution rate and efficiency of bacteria growth in steers},
author = {Firkins, J L and Lewis, S.M. Montgomery, L. and Berger, L L and Merchen, N R and Fahey, Jr, G C},
abstractNote = {Four multiple-fistulated steers (340 kg) were fed a diet containing 50% ground grass hay, 20% dry distillers grains, and 30% concentrate at two intakes (7.2 or 4.8 kg DM/d). Urea (.4 or 1.2% of the diet) was infused continuously into the steers' rumens. The experimental design was a 4 x 4 Latin square with a 2 x 2 factorial arrangement of treatments. Infusing urea at .4 or 1.2% of the diet resulted in ruminal NH/sub 3/ N concentration of 4.97 and 9.10 mg/dl, respectively. Feeding steers at high rather than low intake decreased ruminal and total tract digestibilities of organic matter, NDF, and ADF but did not increase ruminal escape of N. However, apparent N escape from the rumen calculated using purines, but not /sup 15/N, as a bacterial marker was higher when 1.2 vs. .4% urea was infused. Feeding at high rather than at low intake increased the total pool of viable bacteria per gram organic matter fermented in the rumen. Although ruminal fluid outflows and particulate dilution rates were greater when steers were fed at high than low intakes, efficiencies of bacterial protein synthesis were unaffected by intake. The possibility of increased N recycling within the rumen with feeding at the higher intake is discussed.},
doi = {10.3168/jds.S0022-0302(87)80291-6},
journal = {J. Dairy Sci.; (United States)},
number = ,
volume = 70:11,
place = {United States},
year = {1987},
month = {11}
}