• Journal of Animal Science and Technology
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• 제61권3호
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• pp.122-137
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• 2019

Methane, one of the important greenhouse gas, has a higher global warming potential than that of carbon dioxide. Agriculture, especially livestock, is considered as the biggest sector in producing anthropogenic methane. Among livestock, ruminants are the highest emitters of enteric methane. Methanogenesis, a continuous process in the rumen, carried out by archaea either with a hydrogenotrophic pathway that converts hydrogen and carbon dioxide to methane or with methylotrophic pathway, which the substrate for methanogenesis is methyl groups. For accurate estimation of methane from ruminants, three methods have been successfully used in various experiments under different environmental conditions such as respiration chamber, sulfur hexafluoride tracer technique, and the automated head-chamber or GreenFeed system. Methane production and emission from ruminants are increasing day by day with an increase of ruminants which help to meet up the nutrient demands of the increasing human population throughout the world. Several mitigation strategies have been taken separately for methane abatement from ruminant productions such as animal intervention, diet selection, dietary feed additives, probiotics, defaunation, supplementation of fats, oils, organic acids, plant secondary metabolites, etc. However, sustainable mitigation strategies are not established yet. A cumulative approach of accurate enteric methane measurement and existing mitigation strategies with more focusing on the biological reduction of methane emission by direct-fed microbials could be the sustainable methane mitigation approaches.

• Journal of Animal Science and Technology
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• 제45권6호
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• pp.997-1006
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• 2003

본 연구는 우리나라에서 가축 장내발효에 의한 메탄배출 통계 기반을 구축하기 위해 수행되었다. 메탄 배출량을 추정하기 위해 가축은 소, 돼지, 가금, 면양, 산양으로 대분류하였고, 소는 한우와 젖소로 분류하여 각각 한우 송아지, 한우 비육우, 한우 번식우, 젖소 송아지, 젖소 비육우, 착유우로 세분류하였다. Tier 2 방법에 의한 메탄 배출계수는 각 세분류 집단의 가축의 생산성, 생체중, 도체중, 일당 증체량, 소화율을 근거로 하여 산출되었다. 한우의 배출계수는 39～49kg/head/year 정도로 IPCC에서 제시한 Tier 1의 47kg/head/year과 유사한 수준이었고, 젖소의 배출계수는 107 kg/head/year로 Tier 1 배출계수, 118kg/head/ year 보다 다소 낮게 나타났다. Tier 2 방법으로 추정한 가축 장내발효에 의한 메탄 배출량은 2001년, 총 126.8톤이었고 각 세분류별 메탄 배출량은 한우, 젖소, 돼지, 면양, 산양, 말에서 각각 61.70, 47.76, 13.08, 2.25, 0.17, 0.01 톤으로 나타났다. 본 연구에서 온실가스 배출추정 방법으로, Tier 1을 Tier 2로 대체하므로써 우리나라 가축 장내발효에 의한 메탄배출 통계의 정확성과 신뢰성이 개선된 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권6호
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• pp.873-878
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• 2005

Emissions of nitrous oxide (N$_2$O) and methane (CH$_4$) from poultry enteric fermentation were investigated using a respiration chamber. Birds were placed in a respiration chamber for certain intervals during their growing period or for the whole life cycle. The accumulated gas inside the chamber was sampled and analyzed for N$_2$O and CH$_4$ production. A curve for gas production during a life cycle was fitted. The calculated area under the curve estimated the emission factor of poultry enteric fermentation on a life cycle basis (mg bird$^{-1}$ life cycle$^{-1}$). This method can be used to estimate CH$_4$ or N$_2$O emissions from different types of avian species taking into account factors such as diet, season or thermal effects. The CH$_4$/N$_2$O emission factors estimated for commercial broiler chickens, Taiwan country chickens and White Roman Geese were 15.87/0.03, 84.8/16.4 and 1,500/49 (mg bird$^{-1}$ life cycle$^{-1}$), respectively, while the calculated CH$_4$/N$_2$O emission from enteric fermentations were 3.03/0.006, 14.73/2.84 and 9.5/0.31 (Mg year$^{-1}$), respectively in Taiwan in the year of 2000. The described method is applicable to most poultry species and the reported emission factors were applicable to meat type poultry only.

• 한국축산시설환경학회지
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• 제20권4호
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• pp.139-146
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• 2014

This research was conducted to examine the temporal methane ($CH_4$) and nitrous oxide ($N_2O$) emission trends in livestock agriculture from year 1990 to 2011 with Tier 1 national greenhouse gas (GHG) inventory reporting method, which was related to efforts of decreasing GHG emissions and to achievement of voluntary GHG mitigation target. Methane emissions from enteric fermentation were calculated with default $CH_4$ emission factors of IPCC. Methane and $N_2O$ emissions from manure treatment processes were calculated with Tier 1 and mixture of Tier 1 and Tier 2 including $N_2O$ emission factors of manure treatment systems and nitrogen excretion rate of livestock, respectively. According to 2013 National GHG Inventory Monitoring, Reporting, and Verification report, GHG emission fluctuations from enteric fermentation and manure treatment processes were similarto livestock head fluctuation. GHG emissions from enteric fermentation were mainly affected by beef cattle including Hanwoo, while manure treatment processes were affected by various livestock.

• Asian-Australasian Journal of Animal Sciences
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• 제32권4호
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• pp.548-555
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• 2019

Objective: The main objective of this study was to evaluate the effect of different feeding levels of a total mixed ration silage-based diet on feed intake, total tract digestion, enteric methane emissions, and energy partitioning in two beef cattle genotypes. Methods: Six mature bulls (three Thai natives, and three Thai natives - Charolais crossbreeds) were assigned in a replicated $3{\times}3$ Latin square design, with cattle breed genotype in separate squares, three periods of 21 days, and three energy feeding above maintenance levels (1.1, 1.5, and 2.0 MEm, where MEm is metabolizable energy requirement for maintenance). Bulls were placed in a metabolic cage equipped with a ventilated head box respiration system to evaluate digestibility, record respiration gases, and determine energy balance. Results: Increasing the feeding level had no significant effect on digestibility but drastically reduced the enteric methane emission rate (p<0.05). Increasing the feeding level also significantly increased the energy retention and utilization efficiency (p<0.01). The Thai native cattle had greater enteric methane emission rate, digestibility, and energy utilization efficiency than the Charolais crossbred cattle (p<0.05). The daily metabolizable energy requirement for maintenance in Thai native cattle ($388kJ/kg\;BW^{0.75}$, where $BW^{0.75}$ is metabolic body weight) was 15% less than that in Charolais crossbred cattle ($444kJ/kg\;BW^{0.75}$). Conclusion: Our results suggested that the greater feeding level in zebu beef cattle fed above maintenance levels resulted in improved energy retention and utilization efficiency because of the reduction in enteric methane energy loss. The results also indicated higher efficiency of metabolisable energy utilization for growth and a lower energy requirement for maintenance in Bos indicus than in Bos taurus.

• Journal of Animal Science and Technology
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• 제60권6호
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• pp.15.1-15.10
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• 2018

Methane emission from the enteric fermentation of ruminant livestock is a main source of greenhouse gas (GHG) emission and a major concern for global warming. Methane emission is also associated with dietary energy lose; hence, reduce feed efficiency. Due to the negative environmental impacts, methane mitigation has come forward in last few decades. To date numerous efforts were made in order to reduce methane emission from ruminants. No table mitigation approaches are rumen manipulation, alteration of rumen fermentation, modification of rumen microbial biodiversity by different means and rarely by animal manipulations. However, a comprehensive exploration for a sustainable methane mitigation approach is still lacking. Dietary modification is directly linked to changes in the rumen fermentation pattern and types of end products. Studies showed that changing fermentation pattern is one of the most effective ways of methane abatement. Desirable dietary changes provide two fold benefits i.e. improve production and reduce GHG emissions. Therefore, the aim of this review is to discuss biology of methane emission from ruminants and its mitigation through dietary manipulation.

• 농업과학연구
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• 제45권3호
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• pp.463-473
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• 2018

The objective of this study was to investigate the effects of dietary hydrolysable tannin on growth performance and methane emissions of Hanwoo beef cows. Fifteen cows participated in a seven-week experiment. The cows were stratified by initial methane emissions and assigned to one of two treatments: Control and tannin supplementation. Commercial hydrolysable tannin was top-dressed to a concentrate mix at 3 g/kg based on the dry matter. Enteric methane production was measured for 4 consecutive days at 1 week before and 1, 3 and 7 weeks after the initiation of the experiment using a laser methane detector. The feed intake was measured daily during the methane measurement periods and an additional two days prior to each measurement. The body weight of the cows was measured every 4 weeks. Hydrolysable tannin had no effect (p > 0.05) on body weight, average daily gain, dry matter intake (DMI) and feed conversion ratio. After one week, the methane emission of the tannin supplementation group was 3.66 ppm-m / kg DMI, which was about 3.4% lower (p = 0.078) than that of the control group; however, this tendency disappeared at 3 weeks after the start of the experiment (p > 0.05). The results of this study show that hydrolysable tannin supplementation can reduce enteric methane emissions for a limited period in Hanwoo beef cows. More research, however, is needed to determine the optimal level of hydrolysable tannin supplementation to reduce enteric methane emissions for a longer period without adversely affecting the animal performance of Hanwoo beef cattle.

• Asian Journal of Atmospheric Environment
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• 제9권3호
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• pp.187-193
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• 2015

Livestock is one of the major contributors of greenhouse gases (GHGs). It accounts for 14.5% of the global GHGs emissions like methane ($CH_4$) from enteric fermentation and manure, nitrous oxide ($N_2O$) from manure and fertilizer. Since enteric emissions are a major contributor of $CH_4$ than that of manure emissions hence primary efforts were made on reducing enteric emissions, with minor attention to dung emissions. Many researches were conducted by dietary manipulation to mitigate enteric $CH_4$ emission. However dietary manipulation also had significant effects on manure GHGs emissions too. Several works proved that manure $CH_4$ emissions were increased with high level of concentrate supplementation despite reduction in enteric $CH_4$. Fat and CP content of the diet has shown inconsistent results on manure $CH_4$ emissions. Amount of concentrate in the diet has shown little effect whereas dietary CP content exhibited conflicting effects on manure $N_2O$ emissions.

• 한국초지조사료학회지
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• 제38권1호
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• pp.39-43
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• 2018

The objective of this study was to determine the effect of various roughage sources on nutrient digestibility and enteric methane ($CH_4$), and carbon dioxide ($CO_2$) production in goats. Four castrated black goats ($48.5{\pm}0.6kg$) were individually housed in environmentally controlled respiration-metabolism chambers. The experiment design was a $4{\times}4$ balanced Latin square design with 4 roughage types and 4 periods. Alfalfa, tall fescue, rice straw, and corn silage was used as representative of legume, grass, straw, and silage, respectively. Dry matter digestibility was higher (p < 0.001) in corn silage than in alfalfa hay. Dry matter digestibility of alfalfa hay was higher than those of tall fescue or rice straw (p < 0.001). Neutral detergent fiber digestibility of tall fescue was lower (p < 0.001) than those of alfalfa, rice straw, or corn silage. Daily enteric $CH_4$ production and the daily enteric $CH_4$ production per kilogram of $BW^{0.75}$, dry matter intake (DMI), organic matter intake (OMI), digested DMI, and digested OMI of rice straw did not differ from those of tall fescue but were higher (p < 0.001) than those of alfalfa or corn silage. Roughage type had no effect on enteric $CO_2$ emission in goats. Straw appeared to generate more enteric $CH_4$ production than legume or silage, but similar to grass.

• Journal of Animal Science and Technology
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• 제63권1호
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• pp.16-24
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• 2021

The suppressive effect of monensin as an ionophore-feed additive on enteric methane (CH4) emission and renewable methanogenesis were evaluated. To clarify the suppressive effect of monensin a respiratory trial with head cage was performed using Holstein-Friesian steers. Steers were offered high concentrate diets (80% concentrate and 20% hay) ad libitum with or without monensin, galacto-oligosaccharides (GOS) or L-cysteine. Steers that received monensin containing diet had significantly (p < 0.01) lower enteric CH4 emissions as well as those that received GOS containing diet (p < 0.05) compared to steers fed control diets. Thermophilic digesters at 55℃ that received manure from steers fed on monensin diets had a delay in the initial CH4 production. Monensin is a strong inhibitor of enteric methanogenesis, but has a negative impact on biogas energy production at short retention times. Effects of the activity of coprophagous insects on CH4 and nitrous oxide (N2O) emissions from cattle dung pats were assessed in anaerobic in vitro continuous gas quantification system modified to aerobic quantification device. The CH4 emission from dungs with adults of Caccobius jessoensis Harold (dung beetle) and the larvae of the fly Neomyia cornicina (Fabricius) were compared with that from control dung without insect. The cumulative CH4 emission rate from dung with dung insects decreased at 42.2% in dung beetles and 77.8% in fly larvae compared to that from control dung without insects. However, the cumulative N2O emission rate increased 23.4% in dung beetles even though it reduced 88.6% in fly larvae compared to dung without coprophagous insects. It was suggested that the antibacterial efficacy of ionophores supplemented as a growth promoter still continued even in the digested slurry, consequently, possible environmental contamination with the antibiotics might be active to put the negative impact to land ecosystem involved in greenhouse gas mitigation when the digested slurry was applied to the fields as liquid manure.