I Workshop Internacional de Biometeorologia
“Interação Animal, Homem e Ambiente”
I International Workshop of Biometeorology
“Interaction of Animals, Humans and Environment”
MODELO E NORMAS PARA ENVIO DE RESUMOS
Respiratory volumes of CH4, O2 and CO2 of goats and its association with air temperature and
humidity
Alex Sandro Campos Maia1, Sheila Tavares Nascimento2, Carolina Cardoso Nagib Nascimento3,
1
Professor do departamento de Zootecnia - Grupo de Inovação em Biometeorologia Animal da UNESP, Campus de Jaboticabal, SP. email: alex.maia@fcav.unesp.br
2
Professora assistente do departamento de Zootecnia – UEM, Maringá, PR. e-mail:sheila.tn@gmail.com
3
Doutoranda do Programa de Pós-Graduação em Zootecnia - Grupo de Inovação em Biometeorologia Animal da UNESP, Campus de
Jaboticabal-SP. Bolsista do CNPq. e-mail: carolnagib@yahoo.com.br
Abstract: The aim of this work was to study the influence of air temperature and humidity on the respiratory
volumes (methane, CH4; oxygen, O2; and carbon dioxide, CO2) of ruminants. These volumes were measured
in the exhaled air of Anglo Nubian goats with a system of indirect calorimetry and a facial mask adjusted on
the animals’ muzzle. The results showed an average of CH4 emission of 7.36 kg1 year-1 animal-1, while the
averages of oxygen and carbon dioxide volumes (VO2 and VCO2) were 16.4 and 20.8 L h-1 animal-1,
respectively. During thedata collection the variation of TAR varied between 21 and 31ºC , which influenced
directly the respiratory rate of goats, that increased from 15 to 80breaths. min.-1, and the animals increased
the VO2 consumption from 12.5 to 31 L h-1 and VCO2 production from 13.0 to 30 L h-1. The increase of
respiratory volumes led to an increase of metabolic heat production from 65 to almost140 W m2
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Keywords: indirect calorimetry, green house gases, haldane transformation
Introduction
The measurement of CH4 emission in farmed livestock expelled via eructation through the mouth and
nose is important to inventories (i.e., annual emissions by countries) and mitigation purposes. In the
literature, the researches about the methane emission did not evaluate the impact of meteorological
conditions on the enteric methane emission and its association with other respiratory gases (oxygen and
carbon dioxide) being this the aim of this work. This data can be useful for surveys and to understand the
methane
emission
of
goats
in
tropical
environment
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Material and Methods
The study was conducted in the Animal Biometeorology Laboratory of the São Paulo State
University (UNESP), Campus of Jaboticabal, SP, Brazil (21° 8’S, 48° 11’ W and 583 m altitude). Nine
Anglo Nubian female goats with an average of 3 years old were measured for one hour during nine days and
they were distributed in three classes of body weight: up to 55 kg; between 55 and 65 kg and above 65 kg.
The animals were observed from 08:00 to 17:00 in each day: the first goat was evaluated between 08:00 and
09:00; the second goat, between 09:00 and 10:00, and so on; thus, the ninth animal was evaluated between
16:00 and 17:00. At the end of the trial all the animals were evaluated in each one of the nine days and in all
the periods. The environment variables were measured by Data Loggers (model HOBO, Onset), in regular
ten-minute intervals, air temperature (TAR, °C), black globe temperature (Tg, °C) and relative humidity (UR,
%).
The proportions of carbon dioxide (CO2E), oxygen (O2E),methane (CH4E); and water vapour (H2O) in
the exhaled air of the goats were measured using an indirect calorimetry system with a facial mask adjusted
on the animal`s muzzle. In this system, during each breath, the inlet flow (inspired air) and the outlet flow
(exhaled air) were carried through two valves. The exhaled air coming out from the facial mask was directed
through a tracheal tube (MLA1015 Breathing Tube, ADInstruments, Australia), to the flow head (MLT1.000,
ADInstruments, Australia). The flow head was connected to the gas mixing chamber (MLA246,
ADInstruments, Australia), and this to the spirometer (ML141, ADInstruments, Australia). The gas mixing
chamber was connected to the Field Metabolic System (FMS-1201-05, Sable System, USA) through a plastic
tube (Bevaline Tubing, Sable System, USA). Inside the tube a sample of the exhaled air (150 mL min.-1) was
continuously aspirated by the air pump of the Field Metabolic System and it was forced to the gas analyzers
(H2O, O2 and CO2) also in the FMS. Firstly, the sample went to the H2O vapour analyzer and to the dryer
(Magnesium perchlorate - Mg(ClO4)2); then, it was carried through the CO2 and O2 analyzers, and finally to
the CH4 analyzer (MA-10, Sable System, USA). With a connection between the FMS with the CH 4 analyzer
and with the Spirometer, it was possible the digital reading of H 2O vapour pressure (PEXP , kPa) and the
proportions of CO2E, O2E and CH4E, respectively. Also, were measured the respiratory rate (R R, resp min-1)
and the ventilation (Vm, L s-1).
The volumes of VO2, VCO2 and VCH4 (L s-1) were calculated according to McLean (1972), using a
Haldane transformation for STPD conditions, which means that the gas volume is expressed under Standard
conditions: Temperature (273°K or 0°C), Pressure (760 mm Hg), and Dry (no water vapour),


 1  O 2A  CO2A  CH 4A 
  O 2E 
VO 2  Vm(STPD) O 2A 
 1  O 2E  CO2E  CH 4E 



 1  O 2A  CO2A  CH 4A 

VCO 2  Vm(STPD) CO2E - CO2A 
 1  O 2E  CO2E  CH 4E 


 1  O 2A  CO2A  CH 4A 

VCH 4  Vm(STPD) CH 4E - CH 4A 
 1  O 2E  CO2E  CH 4E 

where,
Vm(STPD)  Vm
Patm  Pexp
Texh
 273.15 


 273.15  101.325 
The proportions of oxygen, carbon dioxide and methane in the atmosphere (O 2A, CO2A and CH4A,
respectively) were analyzed by the FMS and the CH4 analyzer. These measurements were done every time
that the facial mask was taken of the animal´s muzzle; however, the vapour pressure in the atmosphere was
continuously recorded by an external H2O vapour analyzer (PV, kPa) (RH-300, Sable System, USA)
connected to a pump (SS4, Sable System, USA) which aspired continuously an air sample of the atmospheric
air (150 ml min-1) close to the animals’ mask inlet valve.
The quantity of enteric methane exhaled from the respiratory system (eCH 4, g h-1 animal-1) was
measured combining the VCH4 and the Gases Law:
eCH 4  3600
VCH 4 Patm mCH 4
RTA
where Patm (kPa), R = 8,3143 J mol-1 K-1 (universal gas constant), n=1.0 mol (number of gas moles), T AR (K)
and mCH4 = 16g (molecular mass of methane).
The metabolic heat production (q met, W m-2) was calculated in accordance with the equation of Silva
& Maia (2013), adapted from Brouwer (1965) and McLean (1972):
q met 
16180VO 2  5160VCO 2  2420VCH 4
An
where An (m2) is the body surface area of the animal, estimated according to Bennett (1973):
A n  0.171BW 0.5025 , being BW is the body weight of the animals (kg).
Data were analyzed by the least-squares method (Harvey, 1960) using the Statistical Analysis
System (SAS Institute, 1995).
Results and Discussion
The average of CH4 emission and VO2 consumed and CO2 produced were 0.84 ± 0.03 g h-1 animal-1,
16.4 ± 0.24 L h-1 animal-1 and 20.8 ± 0.30 L h-1 animal-1, respectively, being these respiratory gaseous
influenced by live weight and by air temperature. Goats with body weight higher than 65 kg had an average
enteric methane emission of 0.96±0.046 g h-1 animal-1 and higher VCO2 produced (22.85±0.34 L h-1 animal-1)
and VO2 consumed (22.23±0.34 L h-1 animal-1), and consequently a higher qmet (88.33±1.49 W m-2).
The average of TAR, UR and TG was 26.8 ± 0.072ºC, 73.1 ± 0.21% and 26.9 ± 0.070ºC, respectively. A
small daily variation was observed because the research was done inside a facility with animals protected of
solar radiation. However the variation between the sampling days was significant (P<0.05): in the third day,
the averages of TA and UR were 23.3 ± 0.03oC and 78.6 ± 0.17%, respectively; while in the eighth day they
were 29.9 ± 0.06oC and 67.4 ± 0.21%, respectively, causing the increased the volume of VO2 consumption
from 14.5 ± 1.2 to 25.8 ± 1.6 L h-1, the VCO2 produced from 15.0 ± 1.1 to 26.0 ± 1.5 L h-1 and VCH4 from
0.55 ± 0.3 to 1.78 ± 0.4 L h-1.
The variation of TAR from 22 to 31ºC influenced directly the respiratory rate of the goats that
increased from 15 to 60 resp. min.-1, consequently, the animals varied the VO2 consumption from 12.5 to 31
L h-1 and VCO2 produced from 13.0 to 30 L h-1 (Fig. 1). However, in this scenery, the goats increased the qmet
near from 65 to around 140 W m-2. The equations in Fig. 1 indicated that increased of VO2 and VCO2
influenced by RR was not linear, after 40 resp. min.-1 it was weak e after 80 resp. min. -1 remained stable,
being its predicted values of VO2 and VCO2 around 30 L h-1, consequently the qmet remained stable after 80
resp. min.-1.
-1
-1
VCO2 = 31,11+(7,07-31,11)/(1+(FR/19,47)
20
20
10
10
-1
2
Vm(STPD) = -0.03+0.0127FR+-0.0000758FR
2
-1
0,6
R = 0.75 - n = 350
4
0,4
3
2
0,2
1
0
0
20
40
60
80
-1
Respiratory rate (breaths.min )
0
20
40
60
80
Respiratory volume
-1
(L s )
-1
40
30
5
(L h animal )
)
30
6
Volume of CH4 produzed
1,97
2
R = 0,46 - n = 350
-1
(L h animal )
)
(L h animal )
Volume of O2 consumed
2.37
2
R = 0.35 - n = 350
Volume de CO2 produzed
VCO2 = 36.7+(12-36.7)/(1+(FR/35.44)
40
0,0
-1
Respiratory rate (breaths.min )
Figure 1 Variation of ventilation (L h-1), CH4 and CO2 produced; and O2 consumed as a function of the
respiratory rate (breaths min.-1) in Anglo Nubian goats.
Conclusions
The variation of animals’ body weight and air temperature alter directly the volume of CH4, O2 and
CO2 of Anglo Nubian goats managed protected from solar radiation, being CH 4 emission around 7.36 kg
year-1 animal-1.
Acknowledgements
We acknowledge the Foundation of Support in Research of the State of São Paulo (FAPESP) for their
financial support, 2011-17388-6 and proc. 2014-09639-7.
References
BROUWER, E. In Energy Metabolism K.L. Blaxter, editor. London: Academic Press. 441p.1965.
HARVEY, W.R. Least-Squares analysis of data with unequal subclass numbers. Beltaville: U,S,D,A,,
publi, nº 20-8, 1960.
McLean, J.A. On the calculation of heat production from open-circuit calorimetric measurements. British
Journal of Nutrition, 27:597-600, 1972.
SILVA, R.G.; MAIA, A.S.C. Principles of animal biometeorology. New York: Springer, 261p.2013.
SAS INSTITUTE (1995) User’s guide: Statistics, Version 6.10 edition, SAS Institute Inc, Cary, NC.