Academic literature on the topic 'Enteric methane emission'
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Journal articles on the topic "Enteric methane emission"
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Basarab, J. A., E. K. Okine, V. S. Baron, T. Marx, P. Ramsey, K. Ziegler, and K. Lyle. "Methane emissions from enteric fermentation in Alberta’s beef cattle population." Canadian Journal of Animal Science 85, no. 4 (December 1, 2005): 501–12. http://dx.doi.org/10.4141/a04-069.
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This study determined methane emissions from enteric fermentation in Alberta’s beef cattle population by using three methodologies: (1) Intergovernmental Panel on Climate Change (IPCC), Tier 2 guidelines for cattle, (2) actual methane emission factors, expressed as a percentage of gross energy intake, from Canadian research trials and; (3) CowBytes© plus the basic equation developed by Blaxter and Clapperton (1965). Methane emissions, in carbon dioxide equivalents (CO2-E), from Alberta’s beef cattle were determined for 1990, 1996 and 2001. Census of Agriculture numbers for Alberta (Statistics Canada; www.statcan.com) were used and beef cattle were subdivided into 31 distinct categories based on animal type, physiological status, gender, weight, growth rate, activity level and age. Emission of greenhouse gases (GHG) from Alberta ’s beef cattle population, based on IPCC Tier 2 guidelines, were 4.93, 6.57 and 7.01 Mt CO2-E yr-1 in 1990, 1996 and 2001, respectively. Emissions based on methane emission factors from Canadian research trials were 6.23, 8.26 and 8.77 Mt CO2-E yr-1 in 1990, 1996 and 2001, respectively. Estimated methane emissions based on CowBytes© and Blaxter and Clapperton’s (1965) equation were 6.24, 8.35 and 8.94 Mt CO2-E yr-1 in 1990, 1996 and 2001, respectively. The IPCC Tier 2 values were 25.2–26.5% lower than the GHG emissions calculated using emission factors from western Canadian research and 26.7–27.6% lower than GHG emissions calculated from CowBytes© and Blaxter and Clapperton’s equation. IPCC Tier 1 values, which were calculated by multiplying total beef cattle in Alberta by four single value emission factors (beef cows = 72 kg CH4 yr-1; bulls = 75 kg CH4 yr-1; replacement heifers = 56 kg CH4 yr-1; calves, steer and heifer calves for slaughter = 47 kg CH4 yr-1), were 4.83, 6.40 and 6.83 Mt CO2-E in 1990, 1996 and 2001, respectively. Thus, IPCC Tier 1 GHG emissions from enteric fermentation in beef cattle were 2.0–2.7, 28.6–29.1 and 29.2–31.0% lower than those calculated from IPCC Tier 2, western Canadian research trials, and CowBytes© plus Blaxter and Clapperton’s equation, respectively. These results reflect the uncertainty associated with estimating methane emissions from enteric fermentation in cattle and suggest that further research is required to improve the accuracy of methane emissions, particularly for beef cows in their second and third trimester of pregnancy and fed in confinement. They also indicate that a more robust methodology may be to combine CowBytes© predicted dry matter intake with regional specific methane emission factors, where methane loss is expressed as a percentage of gross energy intake. Key words: Cattle, enteric fermentation, greenhouse gas, methane
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Garcia-Apaza, E., O. Paz, and I. Arana. "Greenhouse gas emissions from enteric fermentation of livestock in Bolivia: values for 1990 - 2000 and future projections." Australian Journal of Experimental Agriculture 48, no. 2 (2008): 255. http://dx.doi.org/10.1071/ea07247.
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Gas emissions from enteric fermentation of the domestic livestock contribute to greenhouse gas inventories. Farming activities in Bolivia have nearly doubled methane emissions during the past decade. Methane was the second most important greenhouse gas emitted from human activities in Bolivia according the 1990–2000 GHG inventory. Emissions of methane from enteric fermentation of three regions of Bolivia, highland, valley and lowland, were studied. Atmospheric methane concentrations have increased by a factor of 1.1 to 1.3 in response to this increase and continue to rise. The projection of fermentation enteric gas emissions depends on the increase of the livestock, which was assumed for this study to be linear for 2001–2015 with an increment of 2.27%. In this overview, we examine past trends in the emission of methane due to the enteric fermentation and the sources and sinks that determine its growth rate.
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Herliatika, Agustin, and Yeni Widiawati. "Mitigation of Enteric Methane Emission through Feed Modification and Rumen Manipulation." Indonesian Bulletin of Animal and Veterinary Sciences 31, no. 1 (March 30, 2021): 1. http://dx.doi.org/10.14334/wartazoa.v31i1.2706.
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<p class="awabstrak2">The major of gas emission in the livestock sector are in the form of methane produced by microbial activity in the rumen. The emission of methane cause global warming and is predicted to keep increasing. Feed modification and rumen manipulation are important ways that can be used to mitigate methane emission. Based on this condition, this paper aims to describe several ways to mitigate methane emission using feed and rumen modification for smallholder farmers. Feed modification can be done using high Non-Fiber Carbohydrate (NFC) content in feed and also using balance nutrient feed. Meanwhile, rumen modification can be done through inlcusion of feed additive, microbial products, and oils. Providing feed contains high NFC as much as 21.8-53%DM would decrease methane emission by 3.03-28.33%. While providing feed contains balance nutrients would potentially decrease 21.87% of methane emission. Feed additive addition as much as 0.0011-12%DM decreased 0.59-78% of methane emission. Bacterial inclusion as much as 0.7x10<sup>8</sup> – 3,6x10<sup>11</sup>CFU decreased 0- 18.57% of methane emission. Oil or fat inclusion as much as 6%DM decreased 6.02-24.53% of methane emission. A combination of methods can be used to optimize methane mitigation and it can be applicable for farmers to raise their livestock in friendly environment.</p>
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Hardan, Ali, Philip C. Garnsworthy, and Matt J. Bell. "Variability in Enteric Methane Emissions among Dairy Cows during Lactation." Animals 13, no. 1 (December 31, 2022): 157. http://dx.doi.org/10.3390/ani13010157.
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The aim of this study was to investigate variability in enteric CH4 emission rate and emissions per unit of milk across lactations among dairy cows on commercial farms in the UK. A total of 105,701 CH4 spot measurements were obtained from 2206 mostly Holstein-Friesian cows on 18 dairy farms using robotic milking stations. Eleven farms fed a partial mixed ration (PMR) and 7 farms fed a PMR with grazing. Methane concentrations (ppm) were measured using an infrared CH4 analyser at 1s intervals in breath samples taken during milking. Signal processing was used to detect CH4 eructation peaks, with maximum peak amplitude being used to derive CH4 emission rate (g/min) during each milking. A multiple-experiment meta-analysis model was used to assess effects of farm, week of lactation, parity, diet, and dry matter intake (DMI) on average CH4 emissions (expressed in g/min and g/kg milk) per individual cow. Estimated mean enteric CH4 emissions across the 18 farms was 0.38 (s.e. 0.01) g/min, ranging from 0.2 to 0.6 g/min, and 25.6 (s.e. 0.5) g/kg milk, ranging from 15 to 42 g/kg milk. Estimated dry matter intake was positively correlated with emission rate, which was higher in grazing cows, and negatively correlated with emissions per kg milk and was most significant in PMR-fed cows. Mean CH4 emission rate increased over the first 9 weeks of lactation and then was steady until week 70. Older cows were associated with lower emissions per minute and per kg milk. Rank correlation for CH4 emissions among weeks of lactation was generally high. We conclude that CH4 emissions appear to change across and within lactations, but ranking of a herd remains consistent, which is useful for obtaining CH4 spot measurements.
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Sejian, Veerasamy, Rattan Lal, Jeffrey Lakritz, and Thaddeus Ezeji. "Measurement and prediction of enteric methane emission." International Journal of Biometeorology 55, no. 1 (September 1, 2010): 1–16. http://dx.doi.org/10.1007/s00484-010-0356-7.
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Hristov, Alexander N., Joonpyo Oh, Fabio Giallongo, Tyler W. Frederick, Michael T. Harper, Holley L. Weeks, Antonio F. Branco, et al. "An inhibitor persistently decreased enteric methane emission from dairy cows with no negative effect on milk production." Proceedings of the National Academy of Sciences 112, no. 34 (July 30, 2015): 10663–68. http://dx.doi.org/10.1073/pnas.1504124112.
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A quarter of all anthropogenic methane emissions in the United States are from enteric fermentation, primarily from ruminant livestock. This study was undertaken to test the effect of a methane inhibitor, 3-nitrooxypropanol (3NOP), on enteric methane emission in lactating Holstein cows. An experiment was conducted using 48 cows in a randomized block design with a 2-wk covariate period and a 12-wk data collection period. Feed intake, milk production, and fiber digestibility were not affected by the inhibitor. Milk protein and lactose yields were increased by 3NOP. Rumen methane emission was linearly decreased by 3NOP, averaging about 30% lower than the control. Methane emission per unit of feed dry matter intake or per unit of energy-corrected milk were also about 30% less for the 3NOP-treated cows. On average, the body weight gain of 3NOP-treated cows was 80% greater than control cows during the 12-wk experiment. The experiment demonstrated that the methane inhibitor 3NOP, applied at 40 to 80 mg/kg feed dry matter, decreased methane emissions from high-producing dairy cows by 30% and increased body weight gain without negatively affecting feed intake or milk production and composition. The inhibitory effect persisted over 12 wk of treatment, thus offering an effective methane mitigation practice for the livestock industries.
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Hristov, Alexander N. "347 Enteric Methane: Current Measurement and Assessment Techniques." Journal of Animal Science 99, Supplement_3 (October 8, 2021): 194–95. http://dx.doi.org/10.1093/jas/skab235.351.
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Abstract Enteric methane (ECH4) emissions from ruminants can be measured directly or indirectly using various techniques and recent reviews have discussed advantages and disadvantages of these techniques. The GLOBAL NETWORK project (GN; an international consortium of animal scientists) examined techniques for measuring ECH4, including respiration chambers, the sulfur hexafluoride tracer (SF6) technique, and techniques based on short-term measurements of gas concentrations in samples of exhaled air. The latter category includes automated head chambers (i.e., the GreenFeed system; GF), use of carbon dioxide as a marker, and (handheld) laser methane detection. The conclusion from this analysis was that “there is no ‘one size fits all’ method for measuring ECH4 emission by individual animals” and appropriate and frequent calibrations and recovery tests are necessary with all methods. The team also concluded that the need for screening large numbers of animals (for example, for genomic studies), does not justify the use of measurement methods that are inaccurate. Timing of sampling/data collection is critical for the spot-sampling techniques, such as GF. It is a well-established fact that ECH4 emission is closely related to animal’s dry matter intake (DMI) and feeding patterns. Therefore, data collection using GF has to be sufficiently long and frequent, during both day and night hours, to fully represent the diurnal patter of ECH4 emission. The in vitro gas production and analysis technique can be used to screen feed additives or other ECH4 mitigation treatments, but data must be always confirmed/supported by animal (preferably long-term) studies. ECH4 emission can be also predicted based on dietary or animal variables. Large databases developed by the GN project have confirmed that DMI is driving ECH4, but other factors, such as dietary neutral detergent fiber, milk yield and composition (dairy cows), or dietary forage inclusion and animal’s body weight (beef cattle) can improve prediction accuracy.
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Million, Tadesse, Getahun Kefale, and Galmessa Ulfina. "Estimation of enteric methane emission factor in cattle species in Ethiopia using IPCC tier 2 methodology." Annals of Environmental Science and Toxicology 6, no. 1 (March 12, 2022): 013–18. http://dx.doi.org/10.17352/aest.000047.
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Aims: The livestock production system contributes to global climate change directly through the production of methane (CH4) from enteric fermentation, CH4 and nitrous oxide (N2O) from manure management. Enteric CH4 emission from livestock is the major contributor to greenhouse gas (GHG) emission from livestock in Ethiopia. National inventory and reporting of enteric CH4 emission in cattle species in Ethiopia are based on default emission factor (tier 1 methodology) developed by Intergovernmental Panel on Climate Change (IPCC). These enteric CH4 emissions are influenced by different factors such as livestock feed characteristics, livestock management, and livestock production and productivity. Hence, its estimation requires accurate data specific to the condition of the livestock production system in the country. The objective of this study was to estimate enteric CH4 emission from cattle species in Ethiopia. Methodology: Enteric CH4 emission was estimated using IPCC tier 2 methods using input data collected through survey and literature data on livestock and feed characteristics in Ethiopia. Results: Results indicated that enteric CH4 emission factors among indigenous cattle were 30.27, 18.52, 31.55, 29.82, 32.48, and 12.60 kg per head per year for matured females >2 years old, females 1-2 years, bullocks/oxen, breeding bulls >2 years old, males 1-2 years and calves <1 year’s old, respectively. Among crossbred dairy cattle, enteric CH4 emission factors were found to be 36.21, 19.98, 27.90, 25.51, 5.45 kg per head per year for matured females >2 years, females 1-2 years, matured males >2 years, males 1-2 years and calves <1 year’s age, respectively. The weighted average CH4 emission factor for indigenous cattle and crossbred dairy cattle were 26 and 30.71kg/head/year, respectively. Conclusion: Enteric CH4 emission factors for nondairy indigenous and crossbred cattle using IPCC tier 2 methodology were lower when compared to IPCC tier 1 estimate. Our study recommends IPCC tier 2 methodology, for national enteric CH4 emission inventory and reporting for cattle species in Ethiopia. The present study was based on limited survey and published data, uncertainties may have presented with, some of production and performance data. Further research is required to estimate enteric CH4 emission using more detailed cattle production and feed characterization data.
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Sun, Xuezhao, David Pacheco, and Dongwen Luo. "Forage brassica: a feed to mitigate enteric methane emissions?" Animal Production Science 56, no. 3 (2016): 451. http://dx.doi.org/10.1071/an15516.
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A series of experiments was conducted in New Zealand to evaluate the potential of forage brassicas for mitigation of enteric methane emissions. Experiments involved sheep and cattle fed winter and summer varieties of brassica forage crops. In the sheep-feeding trials, it was demonstrated that several species of forage brassicas can result, to a varying degree, in a lower methane yield (g methane per kg of DM intake) than does ryegrass pasture. Pure forage rape fed as a winter crop resulted in 37% lower methane yields than did pasture. Increasing the proportion of forage rape in the diet of sheep fed pasture linearly decreased methane yield. Feeding forage rape to cattle also resulted in 44% lower methane yield than did feeding pasture. In conclusion, reductions in methane emission are achievable by feeding forage brassicas, especially winter forage rape, to sheep and cattle. Investigating other aspects of these crops is warranted to establish their value as a viable mitigation tool in pastoral farming.
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Villanueva, Cristóbal, Muhammad Ibrahim, and Cristina Castillo. "Enteric Methane Emissions in Dairy Cows with Different Genetic Groups in the Humid Tropics of Costa Rica." Animals 13, no. 4 (February 17, 2023): 730. http://dx.doi.org/10.3390/ani13040730.
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Enteric methane (CH4) is one of the main greenhouse gases emitted in livestock production systems with ruminants. Among the options to reduce such emissions, animal genetics is one of the factors that is taking relevance in recent years. The aim of the present study was to assess the emission of enteric CH4 in dairy cows with different genetic backgrounds. Sixteen cows belonging to the following three genetic groups were selected for this study: seven F1 (50% Jersey × 50% Gyr), five Triple cross (50% Jersey × 31% Holstein × 19% Sahiwal) and four Jersey. Enteric CH4 emissions were measured in all cows for 15 months, at the middle of each month, using the SF6 technique. Enteric CH4 emissions did not differ (p > 0.05) among genetic groups, although it varied with the stage of lactation, due to differences in milk yield and dry matter intake (DMI). Pasture DMI and the intensity of CH4 emissions (g kg−1 DMI) differed (p < 0.05) between dry and lactating cows, with higher DMI in the lactation period, while CH4 emission intensity was higher for dry cows. Cows with the highest proportion of Bos taurus genes presented a higher annual mean methane conversion factor (Ym), with 7.22, 7.05 and 5.90% for the Triple cross, purebred Jersey and F1, respectively. In conclusion, non-significant differences in enteric CH4 emissions and Ym were detected among dairy cows with different genetic backgrounds. However, F1 cows tended to show lower enteric CH4 emission and Ym, compared to those with more Bos taurus genes.
Dissertations / Theses on the topic "Enteric methane emission"
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Wang, Junqin. "Enteric methane emissions from dairy and beef cattle: a meta-analysis." Thesis, Kansas State University, 2014. http://hdl.handle.net/2097/18177.
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Master of ScienceDepartment of Biological and Agricultural Engineering
Zifei Liu
This study reviewed state-of-the-art cattle enteric methane (CH4) emissions with three reported measuring units: g/head/d, g/kg DMI (dry matter intake), and %GEI (gross energy intake). Cattle emissions studies included in this meta-analysis were reported from 1995 to 2013. Fifty-five published studies were analyzed with specific objectives: (1) to gain basic information regarding magnitudes and distributions of enteric CH4 emission rates with various units, regions, cattle types and feed situations; (2) to identify and evaluate effects of influence factors or diet mitigation techniques on enteric CH4 emissions; and (3) to evaluate Intergovernmental Panel on Climate Change (IPCC) approaches to estimate enteric CH4 emissions. Emissions data (n=165) with the unit of g/head/d had large variances and non-normal distribution, and were not homogeneous across the studies. Emissions data (n=134) with the unit of g/kg DMI were not homogeneous across the studies, while emissions data (n=76) with the unit of %GEI had small variances and normal distribution, and were homogeneous across the studies. Therefore, data with the unit of %GEI may be better for meta-analysis compared to data with the units of g/head/d and g/kg DMI; however, the number of data with the unit of %GEI was small relative to the number of data with the units of g/head/d and g/kg DMI. Enteric CH4 emissions with the unit of g/head/d are significantly influenced by geographic region, cattle classification, sub-classification, humidity, temperature, body weight, and feed intake. Emissions and feed intake had a strong positive linear relationship with R2 of 0.75 (n=148). Emissions with the unit of g/kg DMI are significantly affected by humidity, body weight, and feed intake. The relationship between emissions and feed intake is positive. Emissions with the unit of %GEI are significantly associated with humidity, production stage, and body weight. IPCC Tier 1 and Tier 2 estimated emissions were approximate to most of the measured enteric CH4 emissions; however, the residuals were not normally distributed. Based on results from PRD method and paired t-tests, IPCC Tier 1 overestimated emissions in Asian studies, underestimated emissions in European studies for beef cattle, and underestimated emissions in Oceanian studies for dairy cattle. IPCC Tier 2 underestimated emissions in Asian studies for beef cattle. The underestimated emissions of IPCC Tier 2 in Asian studies might result from no consideration of effects from production stage and body weight.
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Alemu, Aklilu W. "Modelling greenhouse gas emissions in cattle: From rumen to the whole-farm." Elsevier B.V. (Animal Feed Science and Technology), 2011. http://hdl.handle.net/1993/14668.
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Mathematical modeling in animal agriculture can be applied at various levels including at the tissue, organ, animal, farm, regional and global levels. The purposes of this research were i) to evaluate models used to estimate volatile fatty acid (VFA) and methane (CH4) production and assess their impact on regional enteric CH4 inventory, and ii) to develop a process-based, whole-farm model to estimate net farm GHG emissions. In the first study, four VFA stoichiometric models were evaluated for their prediction accuracy of rumen VFA and enteric CH4 production. Comparison of measured and model predicted values demonstrated that predictive capacity of the VFA models varied with respect to the type of VFA in rumen fluid which impacted estimated enteric CH4 production. Moving to a larger scale assessment, we examined the enteric CH4 inventory from Manitoba beef cattle (from 1990 to 2008) using two mechanistic rumen models that incorporate VFA stoichiometric models: COWPOLL and MOLLY, and two empirical models: Intergovernmental Panel on Climate Change (IPCC) Tier 2 and a nonlinear equation (Ellis). The estimated absolute enteric CH4 production varied among models (7 to 63%) indicating that estimates of GHG inventory depend on model selection. This is an important consideration if the values are to be used for management and/or policy-related decisions. Development of models at the individual farm component level (animal, soil, crop) does not accurately reflect net GHG emissions generated from the whole production system. We developed a process-based, whole-farm model (Integrated Components Model, ICM), using the existing farm component models COWPOLL, manure-DNDC and some aspects of IPCC to integrate farm components and their associated GHG emissions. Estimates of total farm GHG emissions and their relative contribution using the ICM were comparable to estimates using two other whole-farm models (Integrated Farm System Model and Holos model). Variation was observed among models both in estimating whole-farm GHG emissions and the relative contribution of the different sources in the production system. Overall, whole-farm models are required to explore management options that will mitigate GHG emissions and promote best management practices. However, for full assessment of the production system, other benefits of the system (e.g., carbon sequestration, ecosystem services), which are not part of current whole-farm models, must be considered.
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GISLON, GIULIA. "GREENHOUSE GAS EMISSIONS RELATED TO MILK PRODUCTION OF DAIRY COWS." Doctoral thesis, Università degli Studi di Milano, 2020. http://hdl.handle.net/2434/706613.
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With global emissions estimated at 7.1 Gt CO2 eq per annum, livestock represents 14.5% of all human-induced emissions and it is considered to be the largest source of greenhouse gas (GHG) emissions from the agricultural sector. However, livestock can contribute to convert nutrients from plant biomass into animal-sourced foods, which are rich in essential macro and micronutrients in the form of milk and meat, thereby utilizing resources that cannot otherwise be consumed by humans. Livestock also contributes to global food security and poverty reduction, providing regular income to producers. To achieve a sustainable supply of animal origin food, farmers need, therefore, to identify strategies, in terms of livestock management and feeding, forage systems and feed growing practices, that make the best use of available resources and minimize the potential environmental impact. The studies of the PhD thesis were mainly developed inside the Life project “Forage4Climate”, a four years project, aimed at demonstrating that forage systems connected to milk production can promote climate change mitigation. The aim of the PhD thesis was the evaluation of GHG emission, related to dairy cattle milk production. Specific aims were: • to identify and evaluate the most common forage systems adopted in dairy cow farms in the Po plain, selecting the systems that can improve milk production and soil carbon (C) sequestration reducing emissions per kg of milk; • to evaluate commercial diets related to these different forage systems, in order to directly assess their digestibility, milk and methane (CH4) production; • to identify, through a survey analysis, the main ingredients used in the total mixed ration (TMR) of high producing lactating cows, in order to assess the best diet composition that can lead to high feed efficiency (FE) and low global warming potential (GWP) at commercial farms scale; • in a future perspective of circular economy, to study the exploitation of different inedible human by-products as growing substrates for Hermetia Illucens larvae, in order to substitute soybean meal (SBM) in the livestock diets with insect proteins. A total of 46 dairy cattle farms in Lombardy, Piedmont and Emilia-Romagna were visited, in order to map the main forage systems adopted in each area and to characterize them for GHG emission related to milk production (FPCM, fat and protein corrected milk), and soil organic C stock. The evaluation of environmental impact, in terms of GWP, related to the different forage systems was carried out though a Life Cycle Assessment (LCA) method, using the Software SIMAPRO. Six forage systems based on different forages were identified. The main results in terms of GHG per unit milk were: - CONV - Conventional corn silage system: 1.37 kg CO2 eq/kg FPCM (SD 0.26) - HQFS - High quality forage system: 1.18 kg CO2 eq/kg FPCM (SD 0.13) - WICE - Winter cereal silage system: 1.44 kg CO2 eq/kg FPCM (SD 0.43) - MIXED - Mixed less intensive system: 1.36 kg CO2 eq/kg FPCM (SD 0.26) - PR FRESH- Hay and fresh forage system for Parmigiano Reggiano PDO cheese production: 1.51 kg CO2 eq/kg FPCM (SD 0.23) - PR DRY- Hay system for Parmigiano Reggiano PDO cheese production: 1.36 kg CO2 eq/kg FPCM (SD 0.19). The HQFS system registered the lowest value for GWP, mainly due to the higher milk production per cow (daily FPCM/head). More intensive systems, such as HQFS, confirmed that milk production per cow is negatively related to the impact per kilogram of product, as highlighted also by a PROC GLM analysis. The HQFS system also resulted to be more sustainable, in terms of feed self-sufficiency, as it provided a high amount of dry matter (DM) per hectare, consisting of high digestible forages. Despite the lowest value for GWP, the forage system identified as HQFS showed the lowest organic C soil density: 5.6 kg/m2 (SD 1.1). On the contrary, PR FRESH showed the highest value in terms of organic C density in the soil: 9.7 kg/m2 (SD 2.2), compared with an average of 6.7 kg/m2 (SD 0.88) for the other systems. Further investigations are needed to consider environmental sustainability over a wider spectrum. Enteric CH4 was the main contributor to GWP for all forage systems: on average 45.6% (SD 3.89). For this reason, an in vivo evaluation of CH4 and milk production of lactating dairy cows fed four different diets, obtained from the forage systems identified, was performed. Also digestibility of the diets, energy and nitrogen (N) balance were assessed. Four pairs of Italian Friesian lactating cows were used in a repeated Latin Square design, using individual open circuit respiration chambers to determine dry matter intake (DMI), milk production and CH4 emission and to allow total faeces and urine collection for the determination of N and energy balances. Four diets, based on the following main forages, were tested: corn silage (49.3% DM; CS), alfalfa silage (26.8% DM; AS), wheat silage (20.0% DM; WS), hay-based diet (25.3% DM of both alfalfa and Italian ryegrass hays; PR) typical of the area of Parmigiano Reggiano cheese production. Feeding cows with PR diet significantly increased DMI (23.4 kg/d; P=0.006), compared with the others (on average, 20.7 kg/d), while this diet resulted to be the least digestible (e.g. DM digestibility=64.9 vs 71.7% of the other diets, on average). This is probably the reason why, despite higher DMI of cows fed PR diet, the animals did not show higher production, both in terms of milk (kg/d) and energy corrected milk (ECM; kg/d), compared with the other treatments. The urea N concentration was higher in milk of cows fed WS diet (13.8) and lower for cows fed AS diet (9.24). This was also correlated to the highest urinary N excretion (g/d) for cows fed WS diet (189.5 vs 147.0 on average for the other diets). The protein digestibility was higher for cows fed CS and WS diets (on average 68.5%) than for cows fed AS and PR (on average 57.0%); the dietary soybean inclusion was higher for CS and WS than AS and PR. The higher values for aNDFom digestibility were obtained for CS (50.7%) and AS (47.4%) diets. The rumen fermentation pattern was affected by diet; in particular PR diet, characterized by a lower content of NFC and a higher content of aNDFom as compared to CS diet, determined a higher rumen pH and decreased propionate production as compared to CS. Feeding cows with PR diet increased the acetate:propionate ratio in comparison with CS (3.30 vs 2.44 for PR and CS, respectively). Ruminal environment characteristics (i.e higher pH and higher acetate: propionate ratio), together with increased DMI, led cows fed PR DRY diet to have greater (P=0.046) daily production of CH4 (413.4 g/d), compared to those fed CONV diet (378.2 g/d). However, no differences were observed when CH4 was expressed as g/kg DMI or g/kg milk. Hay based diet (PR) was characterized by the lowest digestible and metabolizable energy contents which overall determined a lower NEL content for PR than CS diet (1.36 vs 1.70 Mcal/kg DM respectively for PR and CS diets). In order to meet the high demand of nutrients needed to assure high milk production, in addition to fodder a lot of concentrates are also used in dairy cows’ TMR. A survey analysis conducted in commercial farms was performed to evaluate the GWP of different lactating cow TMR and to identify the best dietary strategies to increase the FE and to reduce the enteric CH4 emission. A total of 171 dairy herds were selected: data about DMI, lactating cows TMR composition, milk production and composition were provided by farmers. Diet GWP (kg CO2 eq) was calculated as sum of GWP of each ingredient considering inputs needed at field level, feed processing and transport. For SBM, land use change was included in the assessment. Enteric CH4 production (g/d) was estimated using the equation of Hristov et al. (2013) in order to calculate CH4 emission for kg of FPCM. The dataset was analysed by GLM and logistic analysis using SAS 9.4. The results of frequency distribution showed that there was a wide variation among farms for the GWP of TMR: approximately 25% of the surveyed farms showed a diet GWP of 15 kg CO2 eq, 20% of 13 kg CO2 eq and 16.7% of 17 kg CO2 eq. The variation among farms is due to the feed used. Among feed, SBM had the highest correlation with the GWP of the TMR with the following equation: TMR GWP (kg CO2 eq) = 2.49*kg SBM + 6.9 (r2=0.547). Moreover, an inclusion of SBM >15% of diet DM did not result in higher milk production with respect to a lower inclusion (≤15%). Average daily milk production of cows was 29.8 (SD 4.83) kg with a fat and protein content (%) of 3.86 (SD 0.22) and 3.40 (SD 0.14), respectively. The average value of DMI (kg/d) of lactating cows was 22.3 (SD 2.23). The logistic analysis demonstrated that a level of corn silage ≤ 30% on diet DM was associated with higher FE. Almost 50% percent of the farms had an average value of 15.0 g CH4/kg FPCM and about 30% a value of 12.5 g CH4/kg FPCM. The results demonstrated that a lower enteric CH4 production was related to inclusion (% on diet DM) of less than 12% of alfalfa hay and more than 30% of corn silage. Diets with more than 34% of NDF determined higher CH4 production (≥14.0 g/kg FPCM) compared with diets with lower NDF content. On the contrary, a lower enteric CH4 production (<14.0 g/kg FPCM) was related to diets characterized by more than 1.61 NEl (Mcal/kg) and more than 4% of ether extract. The variability in the GWP of TMR shows a significant potential to reduce both the GWP of the diet through a correct choice and inclusion level in the ration of the ingredients (mainly SBM) and the possibility to decrease CH4 enteric emission associated to milk production. Looking forward, in order to evaluate the opportunity of alternative protein sources in the cow diet, to reduce SBM, waste production, and competition between animals and human for crops, a study on the effects of different by-products for Hermetia illucens rearing on the chemical composition of larvae and their environmental impact was conducted, even if, according to the European legislation, today the use of insects as feed source is not possible in ruminants. Regarding climate change, okara and brewer’s grains were the most promising substrates: 0.197 and 0.228 kg CO2 eq/kg of larvae fresh weight, respectively. Results from these studies show the importance of adopting a holistic approach for the assessment of GHG emission from milk production. Therefore, any strategy aimed at mitigating CH4 emission of dairy cows must also take into account the possible effect on the other GHGs, as well as the effect on C sequestration. Based on the studies, it could also be worth evaluating novel feed as a new and useful solution for mitigation of GHG emission related to milk production. The thesis highlights essential differences among forage systems and among feed ingredients of cow ration, confirming that there is room for improvement in sustainability of milk production. These issues should be taken into consideration by farmers, technicians and policy makers, considering that sustainability of livestock production will be one of the priorities for humankind in next future.
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Du, Toit Cornelius Jacobus Lindeque. "Mitigation of enteric methane emissions from ruminants in subtropical production systems." Thesis, University of Pretoria, 2017. http://hdl.handle.net/2263/63219.
Full textAbstract:
Globally agriculture and livestock producers have come under increasing pressure over the
environmental impact of production systems. The objectives of this study were to re-calculate the
direct methane (CH4) and nitrous oxide (N2O) emissions of livestock production systems in South
Africa, taking into consideration the uniqueness of the South African scenario and to identify and
evaluate possible greenhouse gas mitigation strategies for extensive production systems. It is
important to generate accurate greenhouse gas (GHG) baseline figures to develop South Africa’s
capacity to understand and reduce GHG emissions emitted from the livestock sector.
Livestock produce GHG’s in the form of methane from enteric fermentation and nitrous oxide and
methane from manure management and manure deposited on pastures and rangeland by grazing
animals. Agriculture, forestry and land use (corrected for carbon sink values) emitted an estimated
4.9% of South African GHG gases in 2004, which makes it the third largest GHG contributor in
South Africa after the energy industry and industrial processes. Livestock produced approximately
27% of the national methane emissions and 98% of the agricultural sector’s methane emissions in
2004.
Methane is a potent GHG that remains in the atmosphere for approximately 9 to 15 years and is 28
times more effective in trapping heat in the atmosphere than carbon dioxide (CO2) over a 100-year
period. Nitrous oxide has an atmospheric lifetime of 150 years and a global warming potential of
265 times that of CO2 over a 100-year period. South African livestock production is based on a unique combination of commercial (intensive and
extensive) and emerging and communal (subsistence) production systems. The levels of productivity
and efficiency in these production systems vary greatly in certain areas and it is important to
distinguish between them when calculating GHG emissions. Previous inventories were conducted
on a national scale utilizing IPCC default values (Tier 1 approach) for some or all of the emission
calculations. These emission factors do not distinguish effectively between classes of animals,
production efficiencies, and production systems. They are often based on assumptions of animals
utilizing diets which are not representative of South African production systems.
The IPCC Tier 2 methodology seeks to define animals, animal productivity, diet quality and
management circumstances to support a more accurate estimate of feed intake for use in estimating
methane production from enteric fermentation. It was also considered important to do separate
calculations for each province as provinces differ in vegetation or biomes and production systems
which may require different approaches to mitigation recommendations. Due to the heterogeneity
of available feed types within South Africa it was considered important to use methodologies that
could reflect such differences and was developed under similar conditions.
The methodology utilized is based on the Australian national greenhouse account’s National
Inventory Report, which contains Australian country-specific and IPCC default methodologies and
emission factors. Emission factors specific to South African conditions and management systems
were calculated where possible. A Tier 2 approach was adopted for all major livestock categories
including privately owned game in accordance with the IPCC Good Practice requirements. Recently
game farming has become a recognized commercial enterprise in the agricultural sector which needs
to be included as an anthropogenic emissions source.
Methane emissions from South African livestock were estimated at 1328 Giga gram (Gg) during
2010. Dairy and beef cattle contributed an estimated 964 Gg or 72.6% of the total livestock methane
emissions in South Africa during 2010. Beef cattle in extensive systems were the largest contributor
(83.3%), followed by dairy cattle (13.5%), and feedlot cattle (3.2%). The estimated direct enteric
methane emission factors for dairy and beef cattle were higher than the IPCC default factors for
Africa. The Eastern Cape recorded the highest dairy and beef cattle methane emissions, whereas
Gauteng showed the highest feedlot methane emissions primarily due to cattle numbers.
Small stock was responsible for 15.6% of the total livestock emissions contributing an estimated
207.7 Gg, with sheep producing 167 Gg and goats producing 40.7 Gg. Calculated enteric methane
emission factors for both commercial and communal sheep were higher than the IPCC default values
for developing countries. A similar tendency was found with goat emission factors. The highest
sheep and goat methane emissions were reported for the Eastern Cape province.
The pig and ostrich industry both contributed approximately 8 Gg CH4 during 2010. The North-
West province produced the highest commercial pig GHG emissions with the highest communal pig
emissions originating from the Eastern Cape. The poultry industry was the largest direct N2O
producer of the non-ruminant livestock industries, contributing 2.3 Gg or 92.8% of the total nonruminant
N2O emissions.
The privately owned game industry contributed an estimated 131.9 Gg of methane emissions with
the provinces of Limpopo, Eastern Cape and Northern Cape being the three largest contributors with
43.4, 37.3 and 21 Gg methane, respectively. The total privately owned game population was
estimated at 2 991 370 animals, utilizing 20.5 million hectares.
Beef cattle are the major contributors to livestock GHG emissions in South Africa followed by
sheep, privately owned game, dairy cattle, goats, pigs, ostriches, equine, and poultry. The IPCC
default values for Africa underestimate emission factors across all livestock categories. The methane emission factors calculated for commercial livestock production systems are more comparable to
emission factors from developed countries and the emerging/communal production systems to those
of developing countries. This emphasizes the need to develop country-specific emission factors
through quantitative research for livestock in all provinces and on all types of production systems to
produce accurate baseline figures, which is critical to future mitigation protocols.
As part of this study fourteen tropical grass species typical of transitional rangeland regions of South
Africa were characterised in terms of chemical composition, in vitro total gas and in vitro methane
production. The results of the study demonstrated that in vitro methane production varied between
tropical grass species typical of transitional rangeland in South Africa. The variation between species
allows for the potential to identify and select species with a lower enteric methane production
potential. Panicum maximum, Eragrostis curvula and Elionurus miticus were the three species
which produced the lowest in vitro methane production but which also had a crude protein (CP)
concentration of more than 3.5% of dry matter (DM) and with an in vitro organic matter digestibility
(IVOMD) above the group average for the study. Furthermore, the results of the study revealed that
in vitro methane production was higher in Decreaser species compared to Increaser species.
Improving the quality of available forages through the use of cultivated pastures and fertilization is
known to improve ruminant production efficiency. The effect of level of nitrogen (N) fertilization
on certain qualitative parameters and in vitro total gas and methane production of improved grass
species commonly utilised in South Africa was evaluated. Treatments included seven grass species
divided into two photosynthetic pathways (C3 and C4) with three levels of N fertilization (0, 50 and
100 kg N/ha). No effect was found for N fertilization on in vitro total gas or methane production.
The CP concentration increased (P < 0.05) and the NDF concentration tended to decrease (P < 0.1)
as the level of N fertilization increased for both C3 and C4 species. Increasing the level of N fertiliser
increased (P < 0.05) the methanogenic potential of Dactylis glomorata, Festuca arundinacea and
Cenchrus ciliaris after the 24 hour incubation period but no effects (P>0.05) were found after the
48 hour incubation period. Results suggests that the stage of physiological development of forages
might have a greater influence on the methanogenic potential of forages compared to the effect of
N fertiliser application.Thesis (PhD)--University of Pretoria, 2017.
Animal and Wildlife Sciences
PhD
Unrestricted
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Bougouin, Adeline. "Identification of milk fatty acids as proxies of the enteric methane emissions in dairy cows." Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC036/document.
Full textAbstract:
Le méthane (CH4) est un puissant gaz à effet de serre produit lors de la fermentation microbienne anaérobie des aliments dans le rumen. L’un des enjeux majeurs pour le secteur de l’élevage est de trouver des stratégies (alimentaires, génétique) pour réduire les émissions de CH4 tout en maintenant les performances animales. Les techniques de mesure de ces émissions sont coûteuses et difficilement utilisables à grande échelle sur le terrain, d’où la nécessité de trouver des alternatives de mesure ou biomarqueurs pour prédire ces émissions. Les acides gras (AG) du lait ont déjà été identifiés comme indicateurs intéressants de la méthanogenèse chez la vache laitière, mais il convient d’améliorer la précision des équations de prédiction du CH4 existantes ainsi que d'élargir leur domaine d'application à tous types de rations. L'objectif de mon travail de thèse a été de confirmer la pertinence des AG du lait comme indicateurs périphériques de la méthanogénèse chez la vache laitière avec diverses conditions nutritionnelles. Deux bases de données regroupant des données individuelles (issues d’une collaboration scientifique internationale) et moyennes (issues de la littérature) de CH4, de composition en AG du lait et d’autres performances et caractéristiques de l’animal, ainsi que des données de composition chimique des rations, ont été créées. Parallèlement, l’acquisition in vivo de données en conditions expérimentales contrôlées pour des rations mal connues ont permis d’incrémenter la base de données individuelles. Des équations de prédiction des émissions de CH4 [en g/jour, g/kg de matière sèche ingérée (MSI), et g/kg de lait] ont été développées à partir de certains AG du lait, utilisés seuls ou combinés à d’autres variables d’ingestion et de performances laitières, représentant alors des modèles complexes. Des relations entre les émissions de CH4 et la teneur de différents AG du lait (C10:0, iso C17:0 + trans-9 C16:1, iso C16:0, cis-11 C18:1, cis-15 C18:1, cis-9,cis-12 C18:2, et trans-11,cis-15 C18 :2) ont été mises en évidence, confirmant des voies métaboliques communes dans le rumen entre méthanogenèse et métabolisme lipidique. Les équations sont également liées aux types de régimes à partir desquels elles ont été développées. Les équations simples (AG du lait uniquement) sont moins précises que les complexes (erreurs résiduelles de prédiction, respectivement, de 58.6 g/jour, 2.8 g/kg MSI et 3.7 g/kg lait vs. 42.8 g/jour, 2.5 g/kg MSI et 3.3 g/kg lait). Une différence minimum de 16% de CH4 entre stratégies de réduction pourra être mise en évidence par la meilleure équation de prédiction développée. Des équations basées sur des AG bien déterminés par les méthodes infrarouges devront être testées pour évaluer, en routine et à grande échelle, de nouvelles stratégies de réduction des émissions de CH4 entérique chez la vache laitièreMethane (CH4) is a potent greenhouse gas coming from the anaerobic microbial fermentation of the diet in the rumen. One of the main current challenge for the dairy sector is to find CH4 mitigation strategies (diets or genetics) without altering animal performance. Enteric methane measurement methods are costly and very difficult to apply on a large scale on field. Thus, there is a need to develop alternative measurement methods, such as equations based on proxies to predict CH4 emissions. Milk fatty acids (FA) have been identified as potential predictors of the methanogenesis in dairy cattle, but the prediction ability of extant published CH4 equations must be improved, and their domain of applicability must be enlarged to a wide range of diets. The objective of this PhD thesis was to confirm the potential of milk FA as proxies to predict enteric CH4 emissions in dairy cows fed a wide range of diets. Two databases (based on individual and mean data, respectively) were built thanks to an international collaboration, and gathered data on CH4, milk FA composition, dairy performances, diet and animal characteristics. Two in vivo experiments were conducted with the aim to study the effect of dietary strategies poorly documented, on methanogenesis and milk FA. The data from these experiments were included in the created database. Firstly, simple CH4 prediction equations were developed [g/d, g/kg of DMI (DMI), and g/kg of milk] based only on milk FA, and secondly other variables related to cow intake or characteristics, and dairy performance were added and constituted complex equations. Relationships between CH4 and several milk FA (C10:0, iso C17:0 + trans-9 C16:1, iso C16:0, cis-11 C18:1, cis-15 C18:1, cis-9,cis-12 C18:2, and trans-11,cis-15 C18 :2) were found, confirming common rumen metabolic pathways between methanogenesis and lipid metabolism. Equations were also closely related to the diets included in the database used for their development. Simple equations were less accurate than complex ones (prediction error of 58.6 g/d, 2.8 g/kg DMI and 3.7 g/kg milk vs 42.8 g/d, 2.5 g/kg DMI and 3.3 g/kg milk, respectively). A minimum difference of 16% in CH4 emissions between mitigating strategies can be evidenced with the best prediction equation developed in this PhD. Methane prediction equations based on milk FA well determined by infrared spectrometry methods need to be developed in order to be used on a routine basis and on a large scale. These prediction equations would allow studying the effect of novel mitigation strategies of enteric CH4 emissions in dairy cows
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Stewart, Elizabeth K. "Effect of Tannin-Containing Legume Hays on Enteric Methane Emissions and Nitrogen Partitioning in Beef Cattle." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/7170.
Full textAbstract:
Cattle are responsible for greenhouse gas emissions such as carbon dioxide, methane and nitrous oxide. In particular, the cow-calf phase of production accounts for approximately 80 percent of the total beef production system greenhouse gas emissions. Tannins are chemical compounds found in certain forages and they have the potential to help reduce these negative environmental impacts. Thus, given that the cow-calf phase often relies on feeding hay, feeding tannin-containing hays may represent a significant mitigation practice.
With my MS program, I sought to explore whether tannin-containing hays fed to mother cows and heifers influence methane and nitrogen emissions relative to feeding traditional legume and grass hays . I found that “non-traditional” hays such as cicer milkvetch and tannin-containing hays such as sainfoin, birdsfoot trefoil and small burnet can help mitigate greenhouse gas and nitrogen emissions produced from heifers and mature cows. Therefore, these hays could be used to feed cattle during the fall and winter to help create a more environmentally friendly cow-calf phase of beef production.
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Zhao, Yiguang. "Effects of dietary and animal factors on enteric methane emissions and nitrogen utilisation efficiency in sheep." Thesis, Queen's University Belfast, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709883.
Full textAbstract:
Methane (CH4) emissions and nitrogen (N) excretion in ruminant production systems are major contributors to atmospheric greenhouse gas accumulation and groundwater pollution. This project aimed to evaluate the effects of dietary (fresh grass, grass silage, pelleted grass and concentrates) and animal (breed and sex) factors on CH4 emissions and N utilisation and to develop prediction models for CH4 emissions and N excretion in sheep. During each measurement period, sheep were fed ad libitum once daily in the morning and were housed in individual pens for 14 d before being transferred to individual respiration chambers for 4 d with feed intake, faeces and urine outputs and CH4 emissions measured. Data were analysed using ANOVA to evaluate the effects of diet and animal factors on feed intake, nutrient digestibility, CH4 emissions and N utilisation. Linear and multiple regression equations for CH4 emissions and N excretion were also developed. Feeding pelleted grass, rather than fresh grass or grass silage, reduced CH4 emissions per kg dry matter intake and shifted N excretion from urine to faeces. Feeding concentrate supplementation by 0.5 kg/d with fresh grass had no effect on CH4 emissions per kg feed intake and N retention. Dry matter intake and N intake were the best single predictors for CH4 emissions and N excretion, respectively. However, adding grass nutrient concentrations as supporting factors improved prediction accuracy. Models based on farm level data (animal liveweight and grass chemical composition) showed satisfactory accuracy for use in practice. Increasing feeding level and grass metabolisable energy and water soluble carbohydrate contents, and decreasing grass N content, could optimise the mitigation of both CH4 emissions and N excretion in grazing sheep. The equations provide an approach to quantify CH4 emissions and N excretion and consequently to develop mitigation strategies to reduce the environmental footprint in sheep production systems.
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Pitcher, Lance R. "Beef average daily gain and enteric methane emissions on birdsfoot trefoil, cicer milkvetch and meadow brome pastures." Thesis, Utah State University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1584437.
Full textAbstract:
This thesis project explored the use of perennial legumes, including the non-bloating birdsfoot trefoil (BFT; Lotus corniculatus L.) for beef production. In 2011 and 2012, cattle averaged approximately 300 kg at the beginning of the grazing season, and approximately 450 kg in 2013. Average daily gain on pastures ranged from a low of 0.63 kg d-1 on cicer milkvetch (CMV; Astragalus cicer L.) in 2011 and 2013 to a high of 1.03 kg d-1 on Norcen BFT in 2013. Feedlot gains ranged from 1.14 to 1.57 kg d-1. Blood plasma fatty acids did not differ when feeding treatments were imposed, but at the end of each grazing season saturated and omega-6 fatty acids were elevated in feedlot-fed cattle compared with pasture-fed cattle, while trans-vaccenic acid (TVA) and omega-3 fatty acids were elevated in pasture-fed cattle. The ratio of omega-6 to omega-3 fatty acids was always higher in feedlot-fed cattle at the end of the grazing season, but in 2013, when all cattle were nearing slaughter weight, the omega-6 to omega-3 ratio was 50% higher for feedlot-fed than for BFT-fed cattle and double that of grass-fed cattle. Digestive (enteric) methane (CH4) production of beef cows was lower when cattle grazed BFT and CMV pastures (167 and 159 g CH4 per cow per d, respectively) compared to cows on meadow bromegrass (MB; Bromus riparus Rehmann) (355 g CH4 per cow per d). Meadow bromegrass has more fiber than legume forages, which will increase the proportion of acetate to propionate created by microbial digestion in the rumen, increasing the production and release of CH4. Perennial legume forages fix nitrogen, eliminating the need for chemical nitrogen fertilizer, and tannin-containing legumes can be grazed without risk of bloat. These forages will play an important role in developing more environmentally and economically sustainable agricultural production systems.
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Nogueira, Ricardo Galbiatti Sandoval. "Enteric and feces methane emissions, fermentative ruminal parameters and feeding behavior of cattle fed cottonseed and vitamin E." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/10/10135/tde-02052017-125157/.
Full textAbstract:
Problems about greenhouse gas emissions attributed to cattle production and improvements in the productivity of these animals has been growing and becoming increasingly important. Cattle releases methane as part of their digestive process, and this represents loss of energy for the animal. The decomposition of feces releases methane and it can be recovered by digester and transformed into different types of energy. Thus, aiming to quantify the potential production of enteric methane and anaerobic fecal decomposition, as well as to evaluate ruminal and behavioral parameters of cattle fed with cottonseed and vitamin E. Six cannulated cows (864±16 kg) were distributed in a replicate 3x3 Latin square. Treatments were: 1) control diet; 2) CS: basal diet plus 30% cottonseed and 3) CSVitE: basal diet plus 30% of cottonseed plus 500 UI of vitamin E. Results were compared through orthogonal contrast and values were considered significant when P0,05. No differences were observed for dry matter intake (DMI), as well as digestibility of DM and neutral detergent fiber (NDF). Animals supplemented with cottonseed spent more time eating and ruminating and less time in idles. Reduction in the concentration and production of acetate, butyrate and the acetate: propionate ratio was observed in animals fed cottonseed compared to the control. Enteric methane mitigation was observed for the cottonseed treatments compared to the control. Changes in the substrates characteristics used to load the digesters were observed. However, no differences were verified for the total biogas production, methane yield and capacity to recover the energy of the feces in the form of methane. Inclusion of 30% cottonseed can be used as a strategy to mitigate enteric methane, without causing losses in the DMI, nutrients digestibility and anaerobic digestion of feces. In addition, it promoted favorable changes in the ingestive behavior, ruminal fermentation products, as well as in the energy partition of the gastrointestinal tract. Vitamin E when is used as antioxidant had not effect on ruminal fermentation, feeding behavior and feces anaerobic digestion, thus the inclusion is not advised due absence of positive results.A problemática das emissões de gases de efeito estufa atribuída à produção de bovinos e melhorias na produtividade desses animais vem crescendo e se tornando cada vez mais importante. Bovinos emitem metano como parte do seu processo digestivo, e isto representa perda de energia para o animal. A decomposição das fezes gera metano, este pode ser recuperado por biodigestores e transformado em diferentes tipos de energia. Assim, objetivou-se quantificar o potencial de produção do metano entérico e da decomposição anaeróbia das fezes, bem como avaliar parâmetros ruminais e comportamentais de bovinos alimentados com caroço de algodão e vitamina E. Foram utilizadas seis vacas fistuladas não gestantes e não lactantes (876 kg±16). Os tratamentos foram: 1) Controle: dieta basal; 2) CA: dieta basal mais 30% de caroço de algodão; 3) CAVitE: dieta basal mais 30% de caroço de algodão mais 500 UI vitamina E. O delineamento experimental utilizado foi o quadrado latino. Os resultados foram comparados por contrastes ortogonais e foram considerados significantes valores de P0,05. Não foram verificadas diferenças para o consumo de matéria seca (MS), bem como digestibilidade da MS e da fibra em detergente neutro (FDN). Os animais suplementados com caroço de algodão passaram maior tempo comendo e ruminando e menor tempo em ócio. Houve redução na concentração e produção de acetato, butirato e da relação acetato:propionato dos animais que receberam caroço de algodão comparado ao controle. A inclusão do caroço de algodão provocou mitigação das emissões de metano entérico. Houve alteração nas características dos substratos utilizados para abastecer os biodigestores. No entanto, não foram verificadas diferenças para a produção total de biogás, rendimento de metano e capacidade dos biodigestores em recuperar a energia das fezes na forma de metano. A inclusão de 30% caroço de algodão pode ser utilizada como estratégia para mitigar metano entérico, sem causar perdas no consumo, digestibilidade dos alimentos e na biodigestão anaeróbia das fezes. Além disso, sua inclusão promoveu alterações favoráveis no comportamento ingestivo, nos produtos da fermentação ruminal, bem como na partição de energia do trato gastrointestinal. A vitamina E quando utilizada como antioxidante não possui efeitos sobre a fermentação ruminal, comportamento ingestivo e biodigestão anaeróbia das fezes, assim sua inclusão não é indicada devido a ausência de resultados favoráveis a sua utilização.
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Congio, Guilhermo Francklin de Souza. "Rotational stocking management on elephant grass for dairy cows: grazing strategies, animal productivity, enteric methane and nitrous oxide emissions." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11139/tde-18012019-174106/.
Full textAbstract:
Pasture-based systems are important milk suppliers to dairy industry and thereby will play relevant role to support the growing demand for food. However, this additional milk supply must be obtained through higher yields resulting from intensification of existing farming systems through strategies environmentally friendly and economically profitable towards sustainable intensification. The central hypothesis of this study was that simple grazing management strategies can improve the efficiency while reduce the key environmental issues of tropical pasture-based dairy systems. Two experiments were carried out on a rainfed and non-irrigated elephant grass (Pennisetum purpureum Schum. cv. Cameroon) pasture in Piracicaba, SP, Brazil. The objective of the first experiment was to investigate the influence of two pre-grazing targets (95% and maximum canopy light interception during pasture regrowth; LI95% and LIMAX, respectively) on sward structure and herbage nutritive value, dry matter intake (DMI), milk yield, stocking rate, enteric methane (CH4) emissions by Holstein × Jersey dairy cows, and nitrous oxide fluxes from the soil. Results indicated that pre-grazing canopy height was greater for LIMAX (≈135 cm) than LI95% (≈100 cm) and can be used as a reliable field guide for monitoring sward structure. Grazing management based on the LI95% target improved herbage nutritive value and grazing efficiency, allowing greater DMI, milk yield and stocking rate by dairy cows. Daily enteric CH4 emission was not affected; however, cows grazing elephant grass at LI95% were more efficient and emitted 21% less CH4/kg of milk yield and 18% less CH4/kg of DMI. The 51% increase in milk yield per hectare overcame the 29% increase in enteric CH4 emissions per hectare for the LI95% target. Nitrous oxide fluxes were not affected by pre-grazing targets. Overall, strategic grazing management is an environmentally friendly practice that improves the use efficiency of allocated resources through optimization of processes involving plant, ruminant and their interface, and enhances milk production efficiency of tropical pasture-based systems. Once the ideal pre-grazing target was established during he first experiment (LI95%), the second step consisted of a refinement of the first phase. The second objective was to describe and measure the influence of two timings of new paddock allocation to cows (AM and PM) on herbage chemical composition and DMI, milk yield, milk compostion, and enteric CH4 emissions of Holstein × Jersey dairy cows. Results supported the general understanding of diurnal variation in herbage chemical composition towards greater concentrations of dry matter and non-fibrous carbohydrates, and lower concentration of fiber components in the afternoon herbage. However, the higher nutritive value of the afternoon herbage did not result in increasead DMI and milk yield, or decreased intensity of CH4 emission by dairy cows. Our findings also indicate that new paddock allocation in the afternoon can be a simple and useful grazing strategy that results in greater N partitioning to protein yield, and lower excretion of urea N in milk. The association of LI95% pre-grazing target and PM allocation could bring economic, productive and environmental benefits towards sustainable intensification of tropical pasture-based systems.Sistemas baseados no uso de pastagens são importantes fornecedores de leite para a indústria de latícinios e, dessa forma, terão papel relevante para suportar a crescente demanda por alimentos. No entanto, essa oferta adicional de leite deve ser obtida através de maiores produtividades resultantes da intensificação de sistemas de produção já existentes por meio de estratégias ambientalmente seguras e economicamente rentáveis em direção à intensificação sustentável. A hipótese central deste estudo foi que estratégias simples de manejo do pastejo podem melhorar a eficiência e, ao mesmo tempo, reduzir os principais impactos ambientais dos sistemas de produção animal em pastagens tropicais. Foram realizados dois experimentos em pastagem de capim-elefante (Pennisetum purpureum Schum. Cv. Cameroon) não-irrigada em Piracicaba, SP, Brasil. O objetivo do primeiro experimento foi avaliar a influência de duas metas pré-pastejo (95% e máxima interceptação de luz pelo dossel durante a rebrotação; IL95% e ILMáx, respectivamente) sobre a estrutura do pasto e valor nutritivo da forragem, consumo de matéria seca (CMS), produção de leite, taxa de lotação, emissões de metano entérico (CH4) de vacas HPB × Jersey, e o fluxo de óxido nitroso dos solos. Os resultados indicaram que a altura pré-pastejo foi maior para ILMáx (≈135 cm) do que IL95% (≈100 cm) e pode ser usada como um guia de campo confiável para monitorar a estrutura do pasto. O manejo do pastejo com base nos critérios de IL95% melhorou o valor nutritivo da forragem e a eficiência de pastejo, permitindo maior CMS, produção de leite e taxa de lotação. A emissão diária de CH4 entérico não foi afetada; no entanto, as vacas que pastejaram o capim-elefante manejado por IL95% foram mais eficientes e emitiram 21% menos CH4/kg de leite e 18% menos CH4/kg de MS consumida. O aumento de 51% na produção de leite por hectare superou o aumento de 29% nas emissões de CH4 entérico por hectare para a meta IL95%. Os fluxos de óxido nitroso não foram afetados pelas metas pré-pastejo. De maneira geral, o manejo do pastejo com base na meta IL95% é uma prática ambientalmente segura que melhora a eficiência de uso dos recursos alocados por meio da otimização de processos envolvendo plantas, ruminantes e sua interface, e aumenta a eficiência da produção de leite em sistemas baseados em pastagens tropicais. Uma vez que a meta pré-pastejo ideal foi estabelecida durante o primeiro experimento (IL95%), a segunda etapa consistiu-se em um refinamento da primeira. O segundo objetivo foi descrever e medir a influência de dois horários de alocação de novos piquetes aos animais (AM e PM) sobre a composição química da forragem, CMS, produção e composição do leite, e emissões de CH4 entérico de vacas HPB × Jersey. Os resultados confirmaram a compreensão geral da variação diurna na composição química da forragem em direção a maiores concentrações de matéria seca e de carboidratos não-fibrosos, e menor concentração de componentes da fibra na forragem amostrada pela à tarde. No entanto, o maior valor nutritivo da forragem da tarde não aumentou o CMS e a produção de leite, nem diminuiu a intensidade de emissão de CH4 das vacas leiteiras. Os resultados também indicaram que a alocação à tarde pode ser uma estratégia de manejo simples e útil que resulta em maior partição de N para produção de proteína, e menor excreção de N ureico no leite. A associação da meta pré-pastejo IL95% e a alocação do rebanho para um novo piquete à tarde poderia trazer benefícios econômicos, produtivos e ambientais para a intensificação sustentável de sistemas baseados em pastagens tropicais.
Book chapters on the topic "Enteric methane emission"
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Soren, N. M., Veerasamy Sejian, and P. K. Malik. "Enteric Methane Emission Under Different Feeding Systems." In Climate Change Impact on Livestock: Adaptation and Mitigation, 187–208. New Delhi: Springer India, 2015. http://dx.doi.org/10.1007/978-81-322-2265-1_12.
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Bhatta, Raghavendra, Pradeep Kumar Malik, and Veerasamy Sejian. "Enteric Methane Emission and Reduction Strategies in Sheep." In Sheep Production Adapting to Climate Change, 291–305. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-4714-5_13.
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Buccioni, Arianna, Alice Cappucci, and Marcello Mele. "Methane Emission from Enteric Fermentation: Methanogenesis and Fermentation." In Climate Change Impact on Livestock: Adaptation and Mitigation, 171–86. New Delhi: Springer India, 2015. http://dx.doi.org/10.1007/978-81-322-2265-1_11.
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Cersosimo, Laura M., and André-Denis G. Wright. "Estimation Methodologies for Enteric Methane Emission in Ruminants." In Climate Change Impact on Livestock: Adaptation and Mitigation, 209–20. New Delhi: Springer India, 2015. http://dx.doi.org/10.1007/978-81-322-2265-1_13.
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Bhatta, Raghavendra. "Reducing Enteric Methane Emission Using Plant Secondary Metabolites." In Climate Change Impact on Livestock: Adaptation and Mitigation, 273–84. New Delhi: Springer India, 2015. http://dx.doi.org/10.1007/978-81-322-2265-1_17.
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Valli, C. "Mitigating Enteric Methane Emission from Livestock Through Farmer-Friendly Practices." In Global Climate Change and Environmental Policy, 257–73. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-9570-3_8.
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Soren, N. M., Veerasamy Sejian, Megolhubino Terhuja, and George Dominic. "Enteric Methane Emission in Sheep: Process Description and Factors Influencing Production." In Sheep Production Adapting to Climate Change, 209–33. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-4714-5_10.
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Martin-Rosset, W., M. Vermorel, and G. Fleurance. "Quantitative assessment of enteric methane emission and nitrogen excretion by equines." In Forages and grazing in horse nutrition, 485–92. Wageningen: Wageningen Academic Publishers, 2012. http://dx.doi.org/10.3920/978-90-8686-755-4_66.
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Kamra, D. N., Neeta Agarwal, and L. C. Chaudhary. "Manipulation of Rumen Microbial Ecosystem for Reducing Enteric Methane Emission in Livestock." In Climate Change Impact on Livestock: Adaptation and Mitigation, 255–72. New Delhi: Springer India, 2015. http://dx.doi.org/10.1007/978-81-322-2265-1_16.
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Zaman, M., K. Kleineidam, L. Bakken, J. Berendt, C. Bracken, K. Butterbach-Bahl, Z. Cai, et al. "Greenhouse Gases from Agriculture." In Measuring Emission of Agricultural Greenhouse Gases and Developing Mitigation Options using Nuclear and Related Techniques, 1–10. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-55396-8_1.
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AbstractThe rapidly changing global climate due to increased emission of anthropogenic greenhouse gases (GHGs) is leading to an increased occurrence of extreme weather events such as droughts, floods, and heatwaves. The three major GHGs are carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). The major natural sources of CO2 include ocean–atmosphere exchange, respiration of animals, soils (microbial respiration) and plants, and volcanic eruption; while the anthropogenic sources include burning of fossil fuel (coal, natural gas, and oil), deforestation, and the cultivation of land that increases the decomposition of soil organic matter and crop and animal residues. Natural sources of CH4 emission include wetlands, termite activities, and oceans. Paddy fields used for rice production, livestock production systems (enteric emission from ruminants), landfills, and the production and use of fossil fuels are the main anthropogenic sources of CH4. Nitrous oxide, in addition to being a major GHG, is also an ozone-depleting gas. N2O is emitted by natural processes from oceans and terrestrial ecosystems. Anthropogenic N2O emissions occur mostly through agricultural and other land-use activities and are associated with the intensification of agricultural and other human activities such as increased use of synthetic fertiliser (119.4 million tonnes of N worldwide in 2019), inefficient use of irrigation water, deposition of animal excreta (urine and dung) from grazing animals, excessive and inefficient application of farm effluents and animal manure to croplands and pastures, and management practices that enhance soil organic N mineralisation and C decomposition. Agriculture could act as a source and a sink of GHGs. Besides direct sources, GHGs also come from various indirect sources, including upstream and downstream emissions in agricultural systems and ammonia (NH3) deposition from fertiliser and animal manure.
Conference papers on the topic "Enteric methane emission"
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José Vicente Martí, Fernando Estellés, Aránzazu Villagrá, and Salvador Calvet. "Measuring enteric methane from small ruminants using respiration chambers: assessing potential effects of animal behaviour on the emission results." In 2012 IX International Livestock Environment Symposium (ILES IX). St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2012. http://dx.doi.org/10.13031/2013.41601.
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Huiru Zheng, Haiying Wang, and Tianhai Yan. "Modelling enteric methane emissions from milking dairy cows with Bayesian networks." In 2016 IEEE International Conference on Bioinformatics and Biomedicine (BIBM). IEEE, 2016. http://dx.doi.org/10.1109/bibm.2016.7822764.
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Todd, Richard W., Corey Moffet, James P. S. Neel, Kenneth E. Turner, Jean L. Steiner, and N. Andy Cole. "Enteric methane emissions of beef cows grazing tallgrass prairie pasture on the southern Great Plains." In 10th International Livestock Environment Symposium (ILES X). St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2018. http://dx.doi.org/10.13031/iles.18-102.
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"Dietary mitigation of enteric methane emissions and animal production from ruminants: Plant tannins mitigation options." In Technology Innovations and Collaborations in Livestock Production for Sustainable Food Systems. IAARD Press, 2021. http://dx.doi.org/10.14334/proc.intsem.lpvt-2021-p.2.
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van Breukelen, A. E., M. N. Aldridge, R. F. Veerkamp, L. Koning, L. B. Sebek, and Y. de Haas. "33. Heritability and genetic correlations of enteric methane emissions of dairy cows measured by sniffers and GreenFeed." In World Congress on Genetics Applied to Livestock Production. The Netherlands: Wageningen Academic Publishers, 2022. http://dx.doi.org/10.3920/978-90-8686-940-4_33.
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Chudnovsky, B., I. Chatskiy, and A. Lazebnikov. "Evaluation of Gas Turbine Combustors Running on Renewable Fuels Produced From Carbon Dioxide Aimed for Greenhouse Emission Reduction." In ASME 2021 Power Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/power2021-60860.
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Abstract Over the past decades there has been a dramatic increase in natural gas burning as the benign fossil fuel, offering far lower emissions than oil or coal. Its place had been established in a clean, or at least, cleaner energy future. Today, the national and international energy policy has been shifted to carbon neutrality — achieving net zero carbon emissions — and as result has moved natural gas from the “benign” to the “menace” category At present, there are chiefly two alternatives for fuel carbon neutrality under discussion: power-to-gas (PtG) producing methane (or synthetic natural gas, SNG, hydrogen etc.) and power-to-liquid, which stores electric power in the form of methanol. In opposite to other synthetic or fossil fuels, like synthetic methane, NG or hydrogen, methanol burning leads to significant reductions in emissions of nitrogen oxides without any substantial firing system design change. Burning of synthetic methane or hydrogen requires significant effort for NOx reduction. Hydrogen as a fuel offers many advantages in power production. It is a carbon-free fuel that can decarbonize power and heat generation, and transportation, to help meet long-term CO2 emission-reduction targets. However, things are different for NOx emissions are a different matter. The more hydrogen is added to a NG, the higher the NOx is anticipated. Dry Low NOx (DLN) combustor has traditionally mixed NG with sufficient air upstream the combustor, so burning can take place in a lean atmosphere to maintain a relatively cool flame and thus keep NOx down. That approach does not work so well when more hydrogen enters the picture due to auto ignition occurring in the premix zone. Some companies already have diffusion-type combustor technology where fuel and air are supplied separately. Combustion of hydrogen, specifically in diffusion mode, implies combustion with a hotter flame, leading to higher combustion temperatures and the formation of local hot spots. These, in turn, can cause NOx to increase. The generalized solution is to cool the flame using diluents, such as demineralized water, steam or nitrogen. However, reducing NOx, by dilution reduces efficiency compared to a DLN combustor. Another option of providing wide load range of GT operation, while maintaining low NOx emissions is fuel dilution with flue gas being recirculated from the exhaust (FGR - Flue gas recirculation). The present paper discusses the effect of burning renewable fuels produced from carbon dioxide and hydrogen which are being diluted with a flow of FGR on GT performance and emissions reduction in diffusion combustors. For the prediction of the combustion behavior a methodology that combines experimental work and computational simulations was used. Given the fact that due to the increase in renewable energy introduction into the grid, addition of renewable fuel-based energy produced from carbon dioxide becomes very significant. Hence, the development of enhanced firing systems burning synthetic clean fuels with low emissions is challenging and should be promoted. Using renewable fuels for energy supply would reduce the unfavorable impact of CO2 and allow meeting the targets established in the Kyoto and Paris Protocols.
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Zhang, Kai, Simeon Dybe, Yazhou Shen, Sebastian Schimek, Christian Oliver Paschereit, and Christophe Duwig. "Experimental and Numerical Investigation of Ultra-Wet Methane Combustion Technique for Power Generation." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-16105.
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Abstract Using steam as a heat carrier and working media has merits to increase electric efficiency up to 60% and decrease NOx emission to single-digit compared to dry gas turbine cycles. These attribute primarily to the physical properties of steam as having high heat capacity to reduce local flame temperature, and hence reduce emissions by inhibiting the thermal NOx forward reaction rate. In this work, ultra-high steam content with a steam-to-air mass ratio of up to 40% is premixed with methane-air mixture before entering into a swirl-stabilized HP-burner for combustion. A significant change of flame from V-shape (attached) to M shape (detached) is observed through a transparent combustion chamber whilst changing steam content. The measurement of chemiluminescence OH* is conducted with an intensified CCD-camera band-pass filtered at 320nm. Following these measurements, large eddy simulation is used to capture reacting flow features. Reasonably well agreements between experimental data and numerical results are obtained for both attached and detached flames in terms of the OH* distribution. Slight inconsistency of OH* intensity is mainly due to uncollected wall temperature which leads to either over- or under-prediction of chemical reaction rate depending on the experimental flame positions. Distributed flame front is clearly identified with LES for wet methane combustion associated with 35% steam-to-air ratio corresponding to a high Karlovitz number flame. Slightly unstable combustion is observed when the steam-to-air ratio exceeds 40% featuring an onset of flame blow-off. In addition, interaction between precessing vortex core and the flame is presented for different level of steam dilution, and conclusions are drawn regarding the flame stabilization. The in-depth understanding of the ultra-wet combustion is an important step towards the use of sustainable, steam-diluted biosyngas for electricity production.
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Manikantachari, K. R. V., Scott Martin, Ladislav Vesely, Jose O. Bobren-Diaz, Subith Vasu, and Jayanta Kapat. "A Strategy of Mixture Preparation for Methane Direct-Fired sCO2 Combustors." In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-75557.
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The reactor residence time required for a sCO2 combustor is comparatively higher than an equal power, airdiluted conventional combustor. Therefore, the strategies to reduce the reactor residence time are very important in the design of sCO2 combustors. The current work recommends a method to reduce the residence time requirement in the sCO2 combustion chamber. Here, the combustor is modelled by coupling the perfectly-stirred-reactor (PSR) and plug-flow-reactor (PFR) models along with the detailed Aramco 2.0 combustion chemical kinetic mechanism. The real gas effects are considered by using the Soave-Redlich-Kwong (SRK) equation of state incorporated in CHMEKIN-RG. Though, the CO emission level at the exit of the primary zone of the sCO2 combustor is lower or in some cases equal to the conventional combustor, the further decline of CO in the dilution zone is identified as very poor. Therefore, very high CO levels can be expected at the exit of the sCO2 combustor compared to conventional combustors. CO from the sCO2 combustor exhaust can be eliminated by lean operation of the combustor and the excess O2 retained in the re-cycled CO2 stream due to lean operation can be mixed with primary methane before entering the primary combustion zone. This strategy is shown to reduce the primary zone residence time requirement of sCO2 combustion. However, the minimum level of O2 in the re-cycled CO2 stream is approximately 5000 ppm and the minimum required residence time in this pre-mixing chamber is around 4 ms. Also, it is observed that the primary zone residence time requirement decreases linearly with respect to the O2 level in the re-cycled CO2 stream.
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Genova, Tommy, Michelle Otero, Jonathan Reyes, Kareem Ahmed, and Scott Martin. "Partial Premixing Effects on the Reacting Jet of a High Pressure Axially Staged Combustor." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-15760.
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Abstract The effects of partial premixing on a reacting jet-in-crossflow is investigated in a five atmosphere axially staged combustor at stationary gas turbine relevant conditions. The facility consists of a dump style headend burner that provides a crossflow with a quasi-uniform velocity and temperature profile to the axial stage to isolate the effects of the jet-in-crossflow. The headend burner is run with methane and air at a lean equivalence ratio to match industry emissions standards. For the current work,, the total air to the headend and axial stage is kept constant, and fuel is split between the headend and axial stage to represent different gas turbine loading conditions. For the cases analyzed, the fuel split to the axial stage went up to 25%. The axial stage consists of an optically accessible test section with a coaxial injector that provides variability to how long the methane and air can mix before entering the facility. Three different premixed levels are studied: fully premixed, non-premixed, and partially premixed. The flow-field characteristics of the reacting jet-in-crossflow are analyzed using particle image velocimetry (PIV), and flame behavior is quantified by employing CH* chemiluminescence. NO measurements are made at the exit of the facility using a Horiba emissions analyzer. Two different flames are observed: flames that burn in the leeward recirculation region and flames that burn at the core of the jet.
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Fossen, Morten A., Johann Halvorsrød, Thomas Narvestad, Sander Tjemsland, Ramesh Timsina, and Marianne S. Eikeland. "Aspen Hysys simulation of the methanol synthesis based on gas from biomass gasification." In 63rd International Conference of Scandinavian Simulation Society, SIMS 2022, Trondheim, Norway, September 20-21, 2022. Linköping University Electronic Press, 2022. http://dx.doi.org/10.3384/ecp192052.
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From the gasification of biomass, the produced gas mainly consists of CO, H2, CO2, and CH4. After gas cleaning and conditioning, the syngas obtained can be used to produce methanol, dimethyl ether, polymers, biofuels, etc. Methanol is one of the important industrial chemicals that can be used directly as a fuel or can be blended into conventional fuels. Methanol produced from renewable biomass sources can limit greenhouse gas emissions. Based on data on gas composition from experiments and simulations of the fluidized bed gasification reactor at the University of South-Eastern Norway, the methanol process is simulated with Aspen Hysys. It is desirable to assess how different process parameters affect the yield of methanol production. A Gibbs reactor was modeled with three gas-phase exothermic reactions. The product from the reactor is depressurized to separate gas from the liquid. The liquid enters the distillation column to give CH3OH in the distillate and the water as the bottom product. The yield of methanol is evaluated with regard to pressure, temperature, and H2/CO ratio. The theoretical H2/CO ratio for the methanol synthesis should be approximately between 1,5-2. However, different gas compositions were obtained from different types of fluidizing agents in the gasification reactor, and a low ratio of H2/CO gives a low yield of methanol. Fluidized bed gasification with steam as gasifying agent is preferable to increase the H2/CO ratio and give a higher methanol yield.
Reports on the topic "Enteric methane emission"
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Koning, Lisanne, Johan van Riel, and Léon Šebek. Enteric methane emission of the Dutch dairy herd : Average and variation of enteric methane emission among the Dutch dairy herd. Wageningen: Wageningen Livestock Research, 2020. http://dx.doi.org/10.18174/531257.
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Russell, James R., Justin Bisinger, and Wendy J. Powers. Grazing System Effects on Enteric Methane Emissions from Cows in Southern Iowa Pastures. Ames (Iowa): Iowa State University, January 2016. http://dx.doi.org/10.31274/ans_air-180814-222.
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de Haas, Yvette, Michael Aldridge, and Anouk van Breukelen. Genetics of enteric methane emissions of Dutch dairy cows : Climate Envelop project 2019. Wageningen: Wageningen Livestock Research, 2021. http://dx.doi.org/10.18174/546572.
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Spek, J. W., A. Klop, and L. B. Šebek. Reductie van ammoniak- en methaanemissie via het voerspoor : onderzoek naar de wisselwerking tussen de excretie van Totaal Ammoniakaal Stikstof (TAN) en de emissie van enterisch methaan (CH4) op de Koeien&Kansen praktijkbedrijven in de periode 2010-2013. Wageningen: Wageningen UR Livestock Research, 2017. http://dx.doi.org/10.18174/418263.
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