Declining sulphur hexafluoride permeability of polytetrafluoroethylene membranes causes overestimation of calculated ruminant methane emissions using the tracer technique

Deighton, M. H.; O’Loughlin, B.M.; Williams, S.R.O.; Moate, Peter J.; Kennedy, E.; Boland, T. M.; Eckard, Richard

doi:10.1016/j.anifeedsci.2013.04.021

Cited by 25 publications

(22 citation statements)

References 14 publications

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“…All tracers have weaknesses (Shipley and Clark, 1972) and the variation associated with SF 6 estimates may be in part a consequence of factors affecting the technique itself (Deighton et al, 2013(Deighton et al, , 2014a, or alternatively the variation might be real. Recent work has found that successful use of the SF 6 technique to detect differences in enteric methane emissions due to diets or between animal species may be confounded by diet or genetic effects on body temperature (Deighton et al, 2014b).…”

Section: Greenfeed Vs Sulphur Hexafluoridementioning

confidence: 98%

Methane emissions from cattle: Estimates from short-term measurements using a GreenFeed system compared with measurements obtained using respiration chambers or sulphur hexafluoride tracer

Hammond

Humphries

Crompton

et al. 2015

Animal Feed Science and Technology

105

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a b s t r a c tThe GreenFeed (GF) system (C-Lock Inc., Rapid City, USA) is used to estimate total daily methane emissions of individual cattle using short-term measurements obtained over several days. Our objective was to compare measurements of methane emission by growing cattle obtained using the GF system with measurements using respiration chambers (RC) or sulphur hexafluoride tracer (SF 6 ). It was hypothesised that estimates of methane emission for individual animals and treatments would be similar for GF compared to RC or SF 6 techniques. In experiment 1, maize or grass silage-based diets were fed to four growing Holstein heifers, whilst for experiment 2, four different heifers were fed four haylage treatments. Both experiments were a 4 × 4 Latin square design with 33 day periods. GreenFeed measurements of methane emission were obtained over 7 days (days 22-28) and compared to subsequent RC measurements over 4 days (days 29-33). For experiment 3, 12 growing heifers rotationally grazed three swards for 26 days, with simultaneous GF and SF 6 measurements over two 4 day measurement periods (days 15-19 and days 22-26). Overall methane emissions (g/day and g/kg dry matter intake [DMI]) measured using GF in experiments 1 (198 and 26.6, respectively) and 2 (208 and 27.8, respectively) were similar to averages obtained using RC (218 and 28.3, respectively for experiment 1; and 209 and 27.7, respectively, for experiment 2); but there was poor concordance between the two methods (0.1043 for experiments 1 and 2 combined). Overall, methane emissions measured using SF 6 were higher (P<0.001) than GF during grazing (186 vs. 164 g/day), but there was significant (P<0.01) concordance between the two methods (0.6017). There were fewer methane measurements by GF under grazing conditions in experiment 3 (1.60/day) compared to indoor measurements in experiments 1 (2.11/day) and 2 (2.34/day). Significant treatment effects on methane emission measured using RC and SF 6 were not evident for GF measurements, and the ranking for treatments and individual animals differed using the GF system. We conclude that under our conditions of use the GF system was unable to detect significant treatment and individual animal differences in methane emissions that were Abbreviations: CI, confidence interval; DM(I), dry matter (intake); GF, GreenFeed; LW, live weight; LWG, LW gain; NDIR, non-dispersive infrared; RC, respiration chambers; RFID, radio frequency identification; SF6, sulphur hexafluoride tracer. identified using both RC and SF 6 techniques, in part due to limited numbers and timing of measurements obtained. Our data suggest that successful use of the GF system is reliant on the number and timing of measurements obtained relative to diurnal patterns of methane emission.

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Section: Greenfeed Vs Sulphur Hexafluoridementioning

confidence: 98%

Methane emissions from cattle: Estimates from short-term measurements using a GreenFeed system compared with measurements obtained using respiration chambers or sulphur hexafluoride tracer

Hammond

Humphries

Crompton

et al. 2015

Animal Feed Science and Technology

105

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“…Individual CH 4 emissions for all cows (n = 40) were determined using the calibrated sulfur hexafluoride (SF 6 ) tracer gas technique developed by Zimmerman (1993), with modifications for grazing dairy cattle (Deighton et al, 2013). Permeation tubes containing approximately 2.5 g of SF 6 were manufactured following the method of Deighton et al (2013), balanced by permeation rate [10.0 mg/d (SD = 1.38)] and randomly assigned to the cows within each treatment group. Each cow was orally dosed using a single permeation tube 9 d before collection of gas samples commenced.…”

Section: Enteric Methane Emissions Estimationsmentioning

confidence: 99%

“…Each cow was fitted with a padded canvas saddle and a head collar 3 d before the sample collection period. The saddles, described by Deighton et al (2013), enabled a single 2.14-L gas collection canister to be fitted to the back of each cow. Canisters with an initial vacuum of 90 kPa below atmospheric pressure drew air from a point near each cows nostrils to collect a representative sample of expired and eructated gases.…”

Section: Enteric Methane Emissions Estimationsmentioning

confidence: 99%

Milk production and enteric methane emissions by dairy cows grazing fertilized perennial ryegrass pasture with or without inclusion of white clover

Enríquez-Hidalgo

Gilliland

Deighton

et al. 2014

Journal of Dairy Science

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An experiment was undertaken to investigate the effect of white clover inclusion in grass swards (GWc) compared with grass-only (GO) swards receiving high nitrogen fertilization and subjected to frequent and tight grazing on herbage and dairy cow productivity and enteric methane (CH4) emissions. Thirty cows were allocated to graze either a GO or GWc sward (n=15) from April 17 to October 31, 2011. Fresh herbage [16 kg of dry matter (DM)/cow] and 1 kg of concentrate/cow were offered daily. Herbage DM intake (DMI) was estimated on 3 occasions (May, July, and September) during which 17 kg of DM/cow per day was offered (and concentrate supplementation was withdrawn). In September, an additional 5 cows were added to each sward treatment (n=20) and individual CH4 emissions were estimated using the sulfur hexafluoride (SF6) technique. Annual clover proportion (± SE) in the GWc swards was 0.20 ± 0.011. Swards had similar pregrazing herbage mass (1,800 ± 96 kg of DM/ha) and herbage production (13,110 ± 80 kg of DM/ha). The GWc swards tended to have lower DM and NDF contents but greater CP content than GO swards, but only significant differences were observed in the last part of the grazing season. Cows had similar milk and milk solids yields (19.4 ± 0.59 and 1.49 ± 0.049 kg/d, respectively) and similar milk composition. Cows also had similar DMI in the 3 measurement periods (16.0 ± 0.70 kg DM/cow per d). Similar sward and animal performance was observed during the CH4 estimation period, but GWc swards had 7.4% less NDF than GO swards. Cows had similar daily and per-unit-of-output CH4 emissions (357.1 ± 13.6g of CH4/cow per day, 26.3 ± 1.14 g of CH4/kg of milk, and 312.3 ± 11.5 g of CH4/kg of milk solids) but cows grazing GWc swards had 11.9% lower CH4 emissions per unit of feed intake than cows grazing GO swards due to the numerically lower CH4 per cow per day and a tendency for the GWc cows to have greater DMI compared with the GO cows. As a conclusion, under the conditions of this study, sward clover content in the GWc swards was not sufficient to improve overall sward herbage production and quality, or dairy cow productivity. Although GWc cows had a tendency to consume more and emitted less CH4 per unit of feed intake than GO cows, no difference was observed in daily or per-unit-of-output CH4 emissions.

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“…Since this workshop, there has been considerable research undertaken in Ireland and Australia to improve the accuracy and reliability of the SF 6 technique (e.g. Williams et al 2011a;Deighton et al 2013aDeighton et al , 2014aDeighton et al , 2014bMoate et al 2014cMoate et al , 2015. This research has identified the source of measurement errors within the SF 6 tracer technique and has led to the development and validation of a modified method .…”

Section: Improved Methodology For the Sf 6 Tracer Techniquementioning

confidence: 99%

Reducing the carbon footprint of Australian milk production by mitigation of enteric methane emissions

Moate¹,

Deighton²,

Williams³

et al. 2016

Anim. Prod. Sci.

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Abstract. This review examines research aimed at reducing enteric methane emissions from the Australian dairy industry. Calorimeter measurements of 220 forage-fed cows indicate an average methane yield of 21.1 g methane (CH 4 )/kg dry matter intake. Adoption of this empirical methane yield, rather than the equation currently used in the Australian greenhouse gas inventory, would reduce the methane emissions attributed to the Australian dairy industry by~10%. Research also indicates that dietary lipid supplements and feeding high amounts of wheat substantially reduce methane emissions. It is estimated that, in 1980, the Australian dairy industry produced~185 000 t of enteric methane and total enteric methane intensity was 33.6 g CH 4 /kg milk. In 2010, the estimated production of enteric methane was 182 000 t, but total enteric methane intensity had declined~40% to 19.9 g CH 4 /kg milk. This remarkable decline in methane intensity and the resultant improvement in the carbon footprint of Australian milk production was mainly achieved by increased per-cow milk yield, brought about by the on-farm adoption of research findings related to the feeding and breeding of dairy cows. Options currently available to further reduce the carbon footprint of Australian milk production include the feeding of lipid-rich supplements such as cottonseed, brewers grains, cold-pressed canola, hominy meal and grape marc, as well as feeding of higher rates of wheat. Future technologies for further reducing methane emissions include genetic selection of cows for improved feed conversion to milk or low methane intensity, vaccines to reduce ruminal methanogens and chemical inhibitors of methanogenesis.

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Declining sulphur hexafluoride permeability of polytetrafluoroethylene membranes causes overestimation of calculated ruminant methane emissions using the tracer technique

Cited by 25 publications

References 14 publications

Methane emissions from cattle: Estimates from short-term measurements using a GreenFeed system compared with measurements obtained using respiration chambers or sulphur hexafluoride tracer

Methane emissions from cattle: Estimates from short-term measurements using a GreenFeed system compared with measurements obtained using respiration chambers or sulphur hexafluoride tracer

Milk production and enteric methane emissions by dairy cows grazing fertilized perennial ryegrass pasture with or without inclusion of white clover

Reducing the carbon footprint of Australian milk production by mitigation of enteric methane emissions

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