Methane and nitrous oxide emissions from Canadian dairy farms and mitigation options: An updated review

Abstract

This review examined methane (CH4) and nitrous oxide (N2O) mitigation strategies for Canadian dairy farms. The primary focus was research conducted in Canada and cold climatic regions with similar dairy systems. Meta-analyses were conducted to assess the impact of a given strategy when sufficient data were available. Results indicated that options to reduce enteric CH4 from dairy cows were increasing the dietary starch content and dietary lipid supplementation. Replacing barley or alfalfa silage with corn silage with higher starch content decreased enteric CH4 per unit of milk by 6%. Increasing dietary lipids from 3% to 6% of dry matter (DM) reduced enteric CH4 yield by 9%. Strategies such as nitrate supplementation and 3-nitrooxypropanol additive indicated potential for reducing enteric CH4 by about 30% but require extensive research on toxicology and consumer acceptance. Strategies to reduce emissions from manure are anaerobic digestion, composting, solid–liquid separation, covering slurry storage and flaring CH4, and reducing methanogen inoculum by complete emptying of slurry storage at spring application. These strategies have potential to reduce emissions from manure by up to 50%. An integrated approach of combining strategies through diet and manure management is necessary for significant GHG mitigation and lowering carbon footprint of milk produced in Canada.

Greenhouse gas, water, and land footprint per unit of production of the California dairy industry over 50 years

“…CARB (2017) follows methodology from the US Environmental Protection Agency (EPA) that uses a methane emission factor (Ym) of 4.8% of gross energy intake. The average Ym for North America has consistently been reported to be 5.7% (SE = 0.9; Kebreab et al, 2008;Appuhamy et al, 2016a;Jayasundara et al, 2016), and using this Ym would yield 9.53 Mt of CO 2 e, which is very close to our estimate of 9.65 Mt of CO 2 e based on IPCC AR5 and diets for high-genetic-merit cows. Thoma et al (2013) used the model from Ellis et al (2007), which fitted best to their national database, and if that equation had been used in this study, the estimate would be an adjusted 8.66 Mt of CO 2 e. The Ellis et al (2007) model was not used in this study because it was not in the top 10 models for North American dairy cattle in the evaluation of models conducted by Appuhamy et al (2016a).…”

Development of a Database to Collect Emission Values for Livestock Systems

“…The Web of Science (http://apps.webofknowledge.com/) was used with a specific keyword series for each type of animal production and emission source. To ensure a thorough review, the list of publications was later compared with those of some major international reviews on gas emissions from livestock systems (Giner‐Santonja et al, 2017; Griffing et al, 2007; Hafner et al, 2018; Hassouna et al, 2015a; Hristov et al, 2011; Jayasundara et al, 2016; Meda et al, 2011; Niu et al, 2018; Owen and Silver, 2015; Peyraud et al, 2012; Philippe et al, 2011; Philippe and Nicks, 2015; Sintermann et al, 2012; Webb et al, 2010), which covered different periods from 1981 to 2017.…”

Reduction in Methane Emissions From Acidified Dairy Slurry Is Related to Inhibition of Methanosarcina Species

“…Livestock production is a significant source of methane (CH 4 ) emissions (e.g., 119.1 ± 18.2 Tg in 2011) ( Wolf et al, 2017 ), mainly from enteric fermentation and manure management of dairy farming operations ( Laubach et al, 2015 ; Jayasundara et al, 2016 ; Wolf et al, 2017 ). The large volumes of manure produced annually from intensive dairy farming operations areusually stored in slurry form ( VanderZaag et al, 2013 ), which create environments conducive to CH 4 production ( Grant et al, 2015 ; Petersen, 2018 ).…”