The Whole Farm Approach to Sustainability: Reducing Greenhouse Gas Emissions from Cows to Crops

The Whole Farm Approach to Sustainability: Reducing Greenhouse Gas Emissions from Cows to Crops

The following is information extracted from Innovation Express Magazine produced by Agriculture and Agri-Food Canada. To access the full article, click here: Innovation Express Magazine, Volume 5, Issue 3.

Research teams at the Dairy and Swine Research and Development Centre (Sherbrooke, Quebec) and the Soils and Crops Research and Development Centre (Quebec, Quebec) are working to improve the sustainability of dairy farming in Canada. Teams led by Drs. Benchaar, Massé and Chantigny are using a whole farm approach to analyze greenhouse gas emissions, from cows to crops, and assessing the effects of farm management practices on the overall net reduction of these Greenhouse Gases (GHGs).

Role of Dairy Cow Diets on Methane Emissions

Dr. Chaouki Benchaar and his team in Sherbrooke measured the impact of various diets fed to dairy cows on methane emissions from enteric fermentation (cow belches and flatulence). More than 80% of methane emissions on dairy farms are from enteric fermentation. The process of enteric fermentation results in a loss of energy (emitted as methane gas via cow belches and flatulence) as the cow digests its feed.

The team evaluated various forage-based diets (silages from corn, barley, grass, and legumes) and corn-dried distillers’ grains with solubles (DGGS). They found that when DDGS was included up to 30% of the diet, methane emissions fell by 14%, with no impact on feed intake and milk production. Using corn silage instead of alfalfa silage also reduced methane production by 10%. They also showed that methane energy losses are 14% lower in cows fed corn silage-based diets than in cows fed barley silage-based diets. The team also concluded that a typical lactating dairy cow loses on average 5.9% of the gross energy consumed. This value is lower than the default value (6.5 ± 1%) suggested by the Intergovernmental Panel on Climate Change and used by Environment Canada to calculate inventories of enteric CH4 emissions from dairy cows.

Dr. Benchaar’s work has been supported Dairy Farmers of Canada and its partners under the Dairy Research Cluster since 2010. His future work under the Cluster continues on evaluating the effects of other dietary mitigation strategies and also to develop a tool to estimate on-farm enteric methane emission from individual cows.

In the Barn – First Biofilter Developed to Capture Methane Gas

Dr. Daniel Massé of the Research Centre in Sherbrooke developed the first biofilter to capture very low concentrations of methane gas (200-400 parts per million) in dairy barns and turn it into carbon dioxide. The biofilter only operates in the winter. More research is needed to develop a biofilter that works cost-effectively in temperatures ranging from 5 to 15 degrees Celcius.

Measuring Manure Management Practices to Reduce Methane Emissions

Dr. Daniel Massé is also working on providing baseline data on manure methane, ammonia and nitrous oxide emissions for Canadian farms based on diet, bedding types, manure storage management and land application practices. The data will be used to refine the calculations of the carbon footprint of dairy farms in Canada and to measure the impact of various GHG mitigation practices applied on farms.

Soils and Cropping Practices Tested

Dr. Martin Chantigny and his team in Quebec, is investigating the effects of applying dairy manure in fields as a way to increase carbon sequestration (storage) in soil and reduce GHG emissions from fields.

Dr. Chantigny also tested the manure derived from Dr. Massé’s assays and Dr. Benchaar’s assays from his research on the role of diet in reducing enteric methane emissions. He then determined how feeding strategies abate methane production from the rumen and how manure storage strategies may influence carbon storage in soils and nitrous oxide emissions when the manure is applied to field crops.

For more information on future work in these areas ongoing in the second Dairy Research Cluster, visit the summaries online at www.DairyResearch.ca.