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How much methane do our cows produce in Abbotsford?

April 2, 2015

Our dairy cattle in Abbotsford belch an estimated 2459 tonnes of methane per year, almost 7 x more than the methane coming from manure.

Methane emission from ruminant animals (including beef and dairy cattle) has been commonly known for many years, but attention to greenhouse gas implications are relatively recent. The “burp” emits approximately 87% of the methane produced in the rumen, compared with 13% emitted as flatulence from the small intestine (Murray et al. 1976). Feed additives to increase weight gain and reduce methane emission have been around for many years, but some of the products are now being promoted to reduce GHG emission from dairy and beef cattle in Canada (Boadi et al., 2004, Kebreab et al. 2006, Beauchemin and McGinn 2010). Beauchemin and McGinn (2010) suggest that methane emission from cattle could be reduced by up to 20% through diet and animal breeding.

“About 3 to 12% of the energy consumed by ruminants (cattle and sheep) is converted to methane in the rumen (referred to as enteric methane) and released into the atmosphere. Adopting feeding strategies that will minimize the amount of energy, lost as methane, can improve feed conversion efficiency, improve animal productivity, and is good for the environment.”

Most methane (CH4) that is emitted from livestock originates in the forestomach, also called the rumen, of ruminants (cattle and sheep). This source of methane is called enteric CH4. Only about 10% of the total CH4 from ruminants in Canada is from manure.”  (Beauchemin and McGinn 2010).

Already in 1986, the contribution of global methane production from domestic animals and humans was estimated at 74 Tg per year, with 74% of this coming from cattle (Crutzen et al. 1986).

A research study in Canada that drew attention to methane emissions from dairy cattle was Jackson et al, (1993) where they measured an average methane emission of 542 L of methane per cow per day from a dairy barn.  A review of the literature in that report indicated a wide variation in methane emissions from dairy cattle (96 to 615 L/cow/day), and agreed that variations in methane emissions from dairy cattle could be explained by differences in diet, milk yield and metabolic live weight. Aquerre et al. (2011) measured methane emissions of 538 to 648 L per lactating dairy cow per day (average weight 550 kg), where the higher methane emissions corresponded with a higher forage: concentrate ratio.

Globally, Sevenster and de Jong (2008) report that enteric methane emission (from ruminants such as cattle) produces 26% of anthropogenic methane emissions, compared to manure handling at 3%. For dairy cattle, the contribution of manure to methane emissions from dairy cattle is up to 18% (FAO 2006). They reported that Canadian dairy cattle were the highest emitter of CH4 per dairy cow at approximately 135 kg CH4 per cow, compared with less than 80 kg per cow in New Zealand. In Europe, methane emission factors used to estimate GHG emissions from dairy cattle range from 80 kg CH4 per cow in countries with more extensive dairy production to 130 kg CH4 per cow per day in countries with intensive dairy production (JRC European Commission 2010). This review reported that actual methane emissions may actually be as high as 180 kg CH4 per cow per year based on latest scientific findings and agreed IPCC methodologies. The US estimates 134.8 kg CH4 per cow per year based on Environment Canada information (US EPA 2001). Sun et al. (2008) measured 12 and 18 g CH4 per cow per hour from dry and lactating dairy cattle in California. This corresponds to 105 and 160 kg CH4 per cow per year from dry and lactating dairy cattle.  Lindgren (1980) estimated that enteric methane emissions from dairy cattle increased from 123 kg CH4 per cow per year for cows giving 6000 kg of milk per year, and 136 kg CH4 per cow per year from cows giving 12,000 kg per cow per year. Kirchgessner et al. (1993) estimated that enteric  methane production was 100 kg CH4 per cow per year at 6000 kg milk production and 127 kg CH4 per cow per year at 12,000. Using IPCC Tier 2 guidelines, (Sonesson et al. (2009) estimated 109 kg CH4 per cow per year at 6000 kg of milk per year, and 167 kg CH4 per cow per year at 12,000 kg of milk per year.

GHG emission is also calculated per kg of milk produced, where increasing milk production is associated with increased GHG per cow, but decreased GHG per kg of milk. Cows in Canada produce about .0175 kg CH4 per kg of milk (0.4 kg CO2 equivalent) compared to 0.03 kg CH4 per kg of milk (0.7 kg CO2 equivalent) from dairy cattle in New Zealand (Sevenster and de Jong (2008). Total GHG emissions per kg of milk are estimated at 1.4 kg CO2 equivalent in Europe (JRC European Commission 2010). The contribution of methane among countries in the EU ranged from 0.35 to 0.80 kg CO2 equivalent.

The methodology for calculating greenhouse gas emissions are governed by international law (Amon et al. 2011).

“Reporting bodies are encouraged to use more detailed methodologies than the Tier 2 approach (Tier 3) if possible and if this would result in more accurate reporting.” Amon et al. 2011.

For enteric fermentation estimates a minimal Tier II methodology is required, which consists of 1. definitions for livestock categories, 2. livestock populations by subcategory, and 3. feed intake estimates for the typical animal in each subcategory. Dong et al. (2006) provide an excellent review of the methodology for measuring GHG from livestock and manure management based on the IPCC Guidelines.

In Canada, methane emissions from dairy cattle have been modeled using IPCC Tier 2 methodology (Ominski et al. 2007). They estimated annual methane emissions of 144 kg/cow/year from dairy cattle in BC compared with a Canadian average of 126 kg/cow/year. Methane emissions from heifers in BC using IPCC Tier 2 methodology was 72 kg /animal/year. The higher methane emissions per cow in BC is offset by higher average milk production per cow.  Based on recent science, the estimates of 116.5 and 74.6 kg CH4 per cow per year provided in the 2012 BC Best Practices Methodology are likely low, but are higher than the values of 73 kg CH4 per dairy cow and 46 kg CH4 per non dairy animal in the Fraser Valley Inventory (Levelton 2005).

Enteric methane emission from dairy cattle in Abbotsford

Enteric methane emission from dairy cattle in Abbotsford

In summary, the enteric methane emission estimates of dairy cows and heifers in Abbotsford is 2459 tonnes of methane per year or 51,633 tonnes of CO2 equivalent per year. This is calculated using 2011 census data of 13,886 dairy cows and 6377 heifers, with the most recent emission factors of Ominski et al. (2007) and the IPCC 2007 CO2 equivalent (1 kg methane has the global warming potential of 21 kg carbon dioxide).  This is methane emission that cannot be captured!

Our dairy cows in Abbotsford belch 3.44 megawatt hours of energy on an ongoing basis! Its too bad this cannot be captured!

Our dairy cows in Abbotsford belch an estimated 2500 tonnes of methane per year, almost 7 x more than the methane coming from manure.

References

Amon, B., N. Hutchings, F.P. Vinther, P.D. Nielsen, H.D. Poulsen. I.S. Kristensen and S. Peitrzak. 2011. Analysis of methodologies for calculation greenhouse gas and ammonia emissions and nutrient balances. Eurostat Methodologies and Working Papers ISSN 197-0375.

Aquerre, M.J., M.A. Wattiaux, J.M. Powell, G.A. Broderick and C. Arndt. 2011. Effect of forage-to-concentrate ratio in dairy cow diets on emission of methane, carbon dioxide, and ammonia, lactation performance, and manure excretion. J. Dairy Sci 94: 3081-96.

Beauchemin, K.A., and S.M. McGinn. 2010. Reducing methane in dairy and beef cattle operations: what is feasible?  Prairie Soils and Crops Issue 1, Article 3.  www.prairiesoilsandcrops.ca

Boadi, D., C Benchaa, J. Chiquette and D. Masse. 2004. Mitigations strategies to reduce enteric methane emissions from dairy cows: Update review. Can J. Anim Sci 84: 319-335.

Crutzen, P.J, I. Aselmann and W. Seiler. 1986. Methane production by domestic animals, wild ruminants, other herbivorous fauna, and humans. Tellus. 38B: 271-284.

Dong, H., J. Mangino, T. McAllister, J.L. Hatfield, D.E. Johnson, K.R. Lassey, M.A. de Lima, and A. Romanovskaya. 2006. Emissions from livestock and manure management. Ch. 10 in 2006 IPCC Guidelines for National Greenhouse Gas Inventories.

Jackson, H.A., R.G. Kinsman, D.I Masse, J.A. Munrow, F.D. Sauer. N.K. Patni, D.J. Buckley, E. Pattey, R. Desjardins and M.S. Wolynetz. 1993. Measuring greenhouse gas emissions in a controlled environment dairy barn. ASAE Paper No. 934521.

JRC European Commission. 2010. Evaluation of the Livestock Sector’s Contribution to the EU Greenhouse Gas Emissions. Final Report. Joint Research Centre.

Kebreab, E., K. Clark, C. Wagner-Riddle and J. France. 2006. Methane and nitrous oxide emissions from Canadian animal agriculture: a review.  Can J. Anim. Sci 86: 135-158.

Levelton Consultants 2005. Analysis of best management practices and emission inventory of agricultural sources in the Lower Fraser Valley. Report 404-0342 for FVRD and Environment Canada.

Murray, R.M., A.M. Bryant, and R.A. Leng. 1976. Rates of production of methane in the rumen and large intestine of sheep. Br. J. Nutr. 36: 1-14.

Ominiski, K. H. D.A Boadi, K.M. Wittenberg, D.L. Fulawka, and J.A. Basarab. 2007. Estimates of enteric methane emissions from cattle in Canada using IPCC Tier-2 methodology. Can. J. Anim. Sci 87: 459-467.

Sevenster, M, and F. de Dong. 2008. A Sustainable Dairy Sector: global, regional and lifestyle facts and figures on greenhouse gas emissions. CE Delft Solutions for Environment, Economy and Technology, Delft, Netherlands.

Soneson, U. C. Cederberg, and M. Berglund. 2009. Greenhouse Gas Emissions in Milk Production. Decision support for climate certification. Klimatmarkning Format Report 2009:3 Denmark

Sun, H., S.L. Trabue, K. Scoggin, W.A. Jackson, Y. Pan, I.L. Malkina, J.A. Koziel, and F.M. Mitloehner. 2008. Alcohol, volatile fatty acid, phenol and methane emissions from dairy cows and fresh manure. J. Environ. Qual. 37: 615-22.

US EPA. 2001. Emissions from Animal Feeding Operations. US Environmental Protection Agency. EPA Contract No. 68-D6-0011.

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