Background matters with the SF6 tracer method for estimating enteric methane emissions from dairy cows: A critical evaluation of the SF6 procedure

Williams, S.R.O.; Moate, Peter J.; Hannah, M.C.; Ribaux, B.E.; Wales, W. J.; Eckard, Richard

doi:10.1016/j.anifeedsci.2011.08.013

Cited by 89 publications

(82 citation statements)

References 42 publications

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“…Although SF 6 itself is a potent GHG with a global warming potential of 23,900 and an atmospheric lifetime of 3,200 years (US EPA, 2014), the amount of SF 6 used with the SF 6 methodology is very small. Assuming that cattle permeation tubes each contain 2.5 g of SF 6 and sheep tubes contained 1.0 g SF 6 , Williams et al (2011) estimated that since the establishment of the SF 6 technique, worldwide ruminant research has used a total of less than 12 kg SF 6 , which is minor compared to its industrial use.…”

Section: )mentioning

confidence: 99%

“…Measurements of background CH 4 and SF 6 gases are important requirements of the SF 6 methodology and its precision for estimates of CH 4 emission (Williams et al, 2011;Lassey, 2013;Berndt et al, 2015). High background SF 6 concentrations create uncertainties, with loss of precision and lower accuracy, and a high background gas concentration will contribute substantially to a high variance associated with SF 6 determinations (Lassey, 2013).…”

Section: )mentioning

confidence: 99%

“…Samples are recommended to be taken over 24 h intervals, over a minimum period of five sequential days, with background air samples collected alongside animals at the same time. Daily CH 4 emission is calculated using the ratio of CH 4 :SF 6 in the canister, with each gas corrected for background concentration, in conjunction with the pre-determined SF 6 permeation rate of the tubes, according to Williams et al (2011;Equation 1) where the M subscript indicates a measured sample, and the BG subscript indicates a background concentration:…”

Section: Sulphur Hexafluoride Tracer Techniquementioning

confidence: 99%

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Review of current in vivo measurement techniques for quantifying enteric methane emission from ruminants

Hammond

Crompton

Bannink

et al. 2016

Animal Feed Science and Technology

148

117

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Review of current in vivo measurement techniques for quantifying enteric methane emission from ruminants.Animal Feed Science and Technology http://dx.doi.org/10. 1016/j.anifeedsci.2016.05.018 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. techniques based on short-term measurements of gas concentrations in samples of exhaled air. This includes automated head chambers (e.g. the GreenFeed system), the use of carbon dioxide (CO 2 ) as a marker, and (handheld) laser CH 4 detection. Each of the techniques are compared and assessed on their capability and limitations, followed by methodology recommendations. It is concluded that there is no "one size fits all" method for measuring CH 4 emission by individual animals. Ultimately, the decision as to which method to use should be based on the experimental objectives and resources available. However, the need for high throughput methodology e.g. for screening large numbers of animals for genomic studies, does not justify the use of methods that are inaccurate. All CH 4 measurement techniques are subject to experimental variation and random errors. Many sources of variation must be considered when measuring CH 4 concentration in exhaled air samples without a quantitative or at least regular collection rate, or use of a marker to indicate (or adjust) for the proportion of exhaled CH 4 sampled. Consideration of the number and timing of measurements relative to diurnal patterns of CH 4 emission and respiratory exchange are important, as well as consideration of feeding patterns and associated patterns of rumen 4 fermentation rate and other aspects of animal behaviour. Regardless of the method chosen, appropriate calibrations and recovery tests are required for both method establishment and routine operation. Successful and correct use of methods requires careful attention to detail, rigour, and routine self-assessment of the quality of the data they provide.

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Section: )mentioning

confidence: 99%

Section: )mentioning

confidence: 99%

Section: Sulphur Hexafluoride Tracer Techniquementioning

confidence: 99%

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Review of current in vivo measurement techniques for quantifying enteric methane emission from ruminants

Hammond

Crompton

Bannink

et al. 2016

Animal Feed Science and Technology

148

117

View full text Add to dashboard Cite

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“…In comparison, a review of 13 previous dairy cow studies used an average of 2.5 g SF 6 per cow with an average release rate ranging from 1.2 to 7.0 mg/day (Williams et al, 2011). Tubes were inserted into the rumen 1 week before the first collection period to allow for SF 6 equilibration in the rumen.…”

Section: Location and Weathermentioning

confidence: 99%

“…The small variation among studies employing the SF 6 method has been attributed to inconsistencies in sampling devices among cows, leakage from the SF 6 apparatus (Deighton et al, 2011) or over-estimation of SF 6 release rate from the permeation tube (Storm et al, 2012). Establishing CH 4 levels in background air is a significant challenge for use of the SF 6 method in confined spaces (Williams et al, 2011), and is a possible issue in this experiment since we used only one background air sampler.…”

Section: Diet Qualitymentioning

confidence: 99%

Implications of dairy systems on enteric methane and postulated effects on total greenhouse gas emission

Fredeen

Juurlink²,

Main

et al. 2013

Animal

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The effects of feeding total mixed ration (TMR) or pasture forage from a perennial sward under a management intensive grazing (MIG) regimen on grain intake and enteric methane (EM) emission were measured using chambers. Chamber measurement of EM was compared with that of SF 6 employed both within chamber and when cows grazed in the field. The impacts of the diet on farm gate greenhouse gas (GHG) emission were also postulated using the results of existing life cycle assessments. Emission of EM was measured in gas collection chambers in Spring and Fall. In Spring, pasture forage fiber quality was higher than that of the silage used in the TMR (47.5% v. 56.3% NDF; 24.3% v. 37.9% ADF). Higher forage quality from MIG subsequently resulted in 25% less grain use relative to TMR (0.24 v. 0.32 kg dry matter/kg milk) for MIG compared with TMR. The Fall forage fiber quality was still better, but the higher quality of MIG pasture was not as pronounced as that in Spring. Neither yield of fat-corrected milk (FCM) which averaged 28.3 kg/day, nor EM emission which averaged 18.9 g/kg dry matter intake (DMI) were significantly affected by diet in Spring. However, in the Fall, FCM from MIG (21.3 kg/day) was significantly lower than that from TMR (23.4 kg/day). Despite the differences in FCM yield, in terms of EM emission that averaged 21.9 g/kg DMI was not significantly different between the diets. In this study, grain requirement, but not EM, was a distinguishing feature of pasture and confinement systems. Considering the increased predicted GHG emissions arising from the production and use of grain needed to boost milk yield in confinement systems, EM intensity alone is a poor predictor of the potential impact of a dairy system on climate forcing.

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Methane Production in Ruminant Animals

Zaman

Kleineidam

Bakken

et al. 2021

Measuring Emission of Agricultural Greenhouse Gases and Developing Mitigation Options Using Nuclear and Related Techniques

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Agriculture is a significant source of GHGsglobally and ruminant livestock animals are one of the largest contributors to these emissions, responsible for an estimated 14% of GHGs (CH4and N2O combined) worldwide. A large portion of GHG fluxes from agricultural activities is related to CH4 emissions from ruminants. Both direct and indirect methods are available. Direct methods include enclosure techniques, artificial (e.g. SF6) or natural (e.g. CO2) tracer techniques, and micrometeorological methods using open-path lasers. Under the indirect methods, emission mechanisms are understood, where the CH4 emission potential is estimated based on the substrate characteristics and the digestibility (i.e. from volatile fatty acids). These approximate methods are useful if no direct measurement is possible. The different systems used to quantify these emission potentials are presented in this chapter. Also, CH4 from animal waste (slurry, urine, dung) is an important source: methods pertaining to measuring GHG potential from these sources are included.

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Background matters with the SF6 tracer method for estimating enteric methane emissions from dairy cows: A critical evaluation of the SF6 procedure

Cited by 89 publications

References 42 publications

Review of current in vivo measurement techniques for quantifying enteric methane emission from ruminants

Review of current in vivo measurement techniques for quantifying enteric methane emission from ruminants

Implications of dairy systems on enteric methane and postulated effects on total greenhouse gas emission

Methane Production in Ruminant Animals

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