Estimation of enteric methane emissions trends (1990–2008) from Manitoba beef cattle using empirical and mechanistic models

2011 ◽  
Vol 91 (2) ◽  
pp. 305-321 ◽  
Author(s):  
Aklilu Alemu ◽  
K. H. Ominski ◽  
E. Kebreab

Alemu, A. W., Ominski, K. H. and Kebreab, E. 2011. Estimation of enteric methane emissions trends (1990–2008) from Manitoba beef cattle using empirical and mechanistic models. Can. J. Anim. Sci. 91: 305–321. The objective of this study was to estimate and assess trends in enteric methane (CH4) emissions from the Manitoba beef cattle population from the base year of 1990 to 2008 using mathematical models. Two empirical (statistical) models: Intergovernmental Panel on Climate Change (IPCC) Tier 2 and a nonlinear equation (Ellis), and two dynamic mechanistic models: MOLLY (v3) and COWPOLL were used. Beef cattle in Manitoba were categorized in to 29 distinct subcategories based on management practice, physiological status, gender, age and production environment. Data on animal performance, feeding and management practices and feed composition were collected from the literature as well as from provincial and national sources. Estimates of total enteric CH4 production from the Manitoba beef cattle population varied between 0.9 and 2.4 Mt CO2 eq. from 1990 to 2008. Regardless of the type of models used, average CH4 emissions for 2008 were estimated to be 45.2% higher than 1990 levels. More specifically, CH4 emissions tended to increase between 1990 and 1996. Emissions were relatively stable between 1996 and 2002, increased between 2003 and 2005, but declined by 13.2% between 2005 and 2008, following the same trend as that observed in the beef cattle population. Models varied in their estimates of CH4 conversion rate (Ym, percent gross energy intake), emission factor (kg CH4 head−1 yr−1) and CH4 production. Total CH4 production estimates ranged from 1.2 to 2.0 Mt CO2 eq. for IPCC Tier 2, from 0.9 to 1.5 Mt CO2 eq. for Ellis, from 1.3 to 2.1 Mt CO2 eq. for COWPOLL and from 1.5 to 2.4 Mt CO2 eq. for MOLLY. The results indicate that enteric CH4 estimates and emission trends in Manitoba were influenced by the type of model and beef cattle population. As such, it is necessary to use appropriate models for reliable estimates for enteric CH4 inventory. A more robust approach may be to integrate different models by using mechanistic models to estimate regional Ym values, which may then be used as input for the IPCC Tier 2 model.

2007 ◽  
Vol 87 (3) ◽  
pp. 459-467 ◽  
Author(s):  
K. H. Ominski ◽  
D. A. Boadi ◽  
K. M. Wittenberg ◽  
D. L. Fulawka ◽  
J. A. Basarab

The objective of this study was to estimate enteric methane (CH4) emissions of the Canadian cattle population using the International Panel on Climate Change (IPCC) Tier-2 methodology. Estimates were then compared with IPCC Tier-1 methodology and data from Canadian research studies (CRS). Animal inventory data for the Canadian beef and dairy cattle herd was obtained from Statistics Canada. Information on cattle performance and feeding practices were obtained from provincial cattle specialists via a survey, as well as various published reports. Methane emissions from dairy and beef cattle in Canada for 2001 were 173 030 t yr-1 or 3.6 Mt CO2 eq. and 763 852 t yr-1 or 16.0 Mt CO2 eq., respectively, using Tier-2 methodology. Emissions for dairy cattle ranged from 708 t yr-1 in Newfoundland to 62 184 t yr-1 in Ontario. Emissions for beef cattle ranged from 191 t yr-1 in Newfoundland to 356 345 t yr-1 in Alberta. The national emission factors (kg CH4 yr-1) using IPCC Tier-2 were 73, 126, 90, 94, 40, 75, 63 and 56 for dairy heifers, dairy cows, beef cows, bulls, calves < 1yr, beef heifer replacements, heifers > 1 yr, and steers > 1yr, respectively. Emission factors (kg CH4 yr-1) for the above classes of cattle using IPCC Tier-1 were 56, 118, 72, 75, 47, 56, 47 and 47, respectively. The values were 15.1% higher to 25.3% lower than those obtained using IPCC Tier-2 methodology. When IPCC Tier-2 emission factors were compared with CRS, they were 12.3% lower to 32.6% higher than those obtained using the Tier-2 methodology. In conclusion, national estimates of enteric emissions from the Canadian cattle industry using Tier-1 and Tier-2 methodologies, as well as CRS, differ depending on the methodology used. Tier-2 methodology does allow for the inclusion of information other than population data, including feeding strategies, as well as duration of time in a given production environment. Additional research is required to establish the extent to which feed energy is converted to methane for those production scenarios for which there is no published data. Key words: IPCC Tier-2, IPCC Tier-1, enteric fermentation, cattle, methane, emission factor, methane conversion rate


2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 380-381
Author(s):  
Isabella Cristina F Maciel ◽  
Fabiano A Barbosa ◽  
Thierry R Tomich ◽  
Ramon C Alvarenga ◽  
Ludhiana R Ferreira ◽  
...  

Abstract Crossbreeding has been used to improve performance in beef cattle; however, the effects of breed composition on methane production, yield and intensity from cattle in a tropical intensive system remain unknown. To assess the impact of breed composition on enteric methane emissions, Nellore (NE; yr 1: BW = 171.5 ± 19.4 kg; n = 10; yr 2: BW = 215.8 ± 32.3 kg, n = 25) and Angus-Nellore crossbred (AN; yr 1: BW = 214.2 ± 26.4 kg, n = 10; yr 2: BW = 242.5 ± 32.2 kg, n = 25) were compared. At trial onset, 10 mo old steers grazed Megathyrsus maximus ‘Mombaça’ in the grazing period (GP) and then were finished in a feedlot (FL) (35:65% corn silage:concentrate diet). Steers (n = 8) from each breed composition were randomly selected in GP and FL to measure CH4 production using a sulfur hexafluoride technique and DMI using titanium dioxide. The NE produced 19% less CH4 than AN in GP (17.21 vs 21.17 kg, P &lt; 0.01), and no difference was observed in FL (22.34 vs 22.67 kg, P &gt; 0.10). However, in FL, NE had greater CH4 intensity (CH4/ADG) compared to AN (122.76 vs 97.49 g/kg, P &lt; 0.01). Furthermore, CH4/carcass weight was greater for NE than AN (0.079 vs 0.067 g/kg CW, P &lt; 0.01). Breed composition did not influence CH4 yield (CH4/DMI) in either phase. The percentage CH4/GEI (Ym) for GP was higher for AN than NE (4.5 vs 3.8%), but lower than the IPCC recommended Ym of 6.5%. In FL, Ym was similar between breed composition (5.0%) and greater than the IPCC Ym of 3%. In our study the introduction of Angus into Nellore has potential to reduce CH4 intensity in tropical climates, resulting in less methane emission per kg beef produced.


2016 ◽  
Vol 21 (2) ◽  
pp. 101 ◽  
Author(s):  
Yeni Widiawati ◽  
M.N. Rofiq ◽  
B. Tiesnamurti

<p class="abstrak2">Methane emission from enteric is a sub-category considered under the Agriculture sector greenhouse gas emissions by UNFCCC, thus Indonesia developed calculation on enteric CH<sub>4</sub> EF for ruminant using Tier-2 method as country-specific emission factors (EF). Indonesia has huge amount of beef cattle population, which contributes significant amount to national enteric methane emission. The aim of this study was to estimate enteric methane EF for beef cattle in Indonesia using IPCC Tier-2 method.  The EF generated from this study is then used to estimate the methane emitted from beef cattle. Data on beef cattle population was obtained from BPS, data on energy content of feed, feed intake and digestibility were compiled from laboratory analysis and published paper. Equations were adopted and followed the instruction of IPCC 2006. Local cattle has different CH<sub>4</sub> EF among each sub-category, which are  ranging from 18.18 to 55.89 Kg head-1 yr-1, with the average of 36.75  head-1 yr-1. Imported beef cattle has lower  CH<sub>4</sub> EF (25.49 kg head-1 yr-1) than the average for local beef cattle. Overall, the national CH<sub>4</sub> EF of beef cattle calculated by using IPCC Tier-2 method in Indonesia is 33.14 head-1 yr-1. The value is lower than default EF from IPCC for Asia country (47 kg head-1 yr-1). The conclusion is enteric CH<sub>4</sub> EF for beef cattle in Indonesia calculated using Tier-2 method shows the real livestock system in Indonesia condition. Further research needed to be addressed are calculation of EFs for various breeds and feeding systems, since large variations of breeds and types of feed among provinces in Indonesia.</p>


2005 ◽  
Vol 85 (4) ◽  
pp. 501-512 ◽  
Author(s):  
J. A. Basarab ◽  
E. K. Okine ◽  
V. S. Baron ◽  
T. Marx ◽  
P. Ramsey ◽  
...  

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


PLoS ONE ◽  
2019 ◽  
Vol 14 (7) ◽  
pp. e0220247 ◽  
Author(s):  
Isabella Cristina de Faria Maciel ◽  
Fabiano Alvim Barbosa ◽  
Thierry Ribeiro Tomich ◽  
Luiz Gustavo Pereira Ribeiro ◽  
Ramon Costa Alvarenga ◽  
...  

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