TY - JOUR
T1 - Assessment of rumen processes by selected-ion-flow-tube mass spectrometric analysis of rumen gases
AU - Dewhurst, Richard J.
AU - Evans, Roger T.
AU - Mottram, T. T.
AU - Španěl, P.
AU - Smith, D.
N1 - Dewhurst, R. J., Evans, R. T., Mottram, T. T., Spanel, P., Smith, D. (2001). Assessment of rumen processes by selected-ion-flow-tube mass spectrometric analysis of rumen gases. Journal of Dairy Science, 84, (6), 1438-1444.
Sponsorship: Ministry of Agriculture,
Fisheries and Food (UK) /Grant Agency of the Czech Republic project
number 203/97/P130/The
Royal Society
PY - 2001/6
Y1 - 2001/6
N2 - This work investigated the potential to use measurement
of the concentration of certain gases in the rumen
headspace to gain information about rumen processes
and as a potential diagnostic tool. We used new equipment
(selected-ion-flow-tube mass spectrometer) that
allows rapid and precise analysis of many of the gases
present in a sample. Samples of rumen headspace gas
and corresponding samples of rumen liquor were taken
from three lactating cows, prepared with rumen fistulae,
at intervals after receiving their morning feed allocation
(grass silage and concentrates). Hydrogen sulfide,
methyl sulfide, and dimethyl sulfide, were the predominant
gases that were measured in the rumen
headspace by this technique. The concentrations of
these sulfur compounds declined over the interval after
feeding, mirroring ammonia concentrations measured
in rumen liquor, reflecting their common dependence
on the fermentation of sulfur amino acids. Ammonia
concentrations in rumen headspace gas varied in the
opposite direction to the concentration of ammonia in
rumen liquor and likely depend more on the pH of rumen
liquor. Consideration of the pKa of ammonia suggests
that ammonia concentrations in rumen gas will
be very low below pH 6, representing a useful diagnostic
for subacute ruminal acidosis. Low concentrations of
volatile fatty acids were detected in rumen gas. The
molar proportions of volatile fatty acids were similar
in gas and liquor samples, with rumen gas containing
slightly less acetic acid and disproportionately more
valeric and caproic acids.
AB - This work investigated the potential to use measurement
of the concentration of certain gases in the rumen
headspace to gain information about rumen processes
and as a potential diagnostic tool. We used new equipment
(selected-ion-flow-tube mass spectrometer) that
allows rapid and precise analysis of many of the gases
present in a sample. Samples of rumen headspace gas
and corresponding samples of rumen liquor were taken
from three lactating cows, prepared with rumen fistulae,
at intervals after receiving their morning feed allocation
(grass silage and concentrates). Hydrogen sulfide,
methyl sulfide, and dimethyl sulfide, were the predominant
gases that were measured in the rumen
headspace by this technique. The concentrations of
these sulfur compounds declined over the interval after
feeding, mirroring ammonia concentrations measured
in rumen liquor, reflecting their common dependence
on the fermentation of sulfur amino acids. Ammonia
concentrations in rumen headspace gas varied in the
opposite direction to the concentration of ammonia in
rumen liquor and likely depend more on the pH of rumen
liquor. Consideration of the pKa of ammonia suggests
that ammonia concentrations in rumen gas will
be very low below pH 6, representing a useful diagnostic
for subacute ruminal acidosis. Low concentrations of
volatile fatty acids were detected in rumen gas. The
molar proportions of volatile fatty acids were similar
in gas and liquor samples, with rumen gas containing
slightly less acetic acid and disproportionately more
valeric and caproic acids.
KW - Dairy cow
KW - Gas analysis
KW - Mass spectrometry
KW - Rumen
UR - http://www.scopus.com/inward/record.url?scp=0035379655&partnerID=8YFLogxK
U2 - 10.3168/jds.S0022-0302(01)70176-2
DO - 10.3168/jds.S0022-0302(01)70176-2
M3 - Article
SN - 0022-0302
VL - 84
SP - 1438
EP - 1444
JO - Journal of Dairy Science
JF - Journal of Dairy Science
IS - 6
ER -