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Submitted to: Extension Fact Sheets
Publication Type: Other Publication Acceptance Date: 2/2/2009 Publication Date: 3/5/2009 Citation: Rotz, C.A. 2009. The Dairy Greenhouse Gas Model: A Tool for estimating greenhouse gas emissions and the carbon footprint of dairy production systems. Northeast Pasture Consortium Fact Sheets. p. 1. Interpretive Summary: An interpretive summary is not required. Technical Abstract: Greenhouse gas (GHG) emissions and their potential impact on the environment has become an important national and international concern. Animal agriculture is a recognized source of GHG emissions, but good information does not exist on the net emissions from our farms. A software tool called the Dairy Greenhouse Gas Model or DairyGHG was created to quantify these emissions over a range in farm management options. This tool calculates the carbon footprint of a dairy production system as the net exchange of all GHGs in carbon dioxide equivalent (CO2e) units per unit of milk produced. Primary emission sources include enteric fermentation, manure handling facilities, cropland used in feed production, and the combustion of fuel in the machinery used to produce feed and handle manure. Secondary emissions include those occurring during the production of resources used on the farm. A long-term carbon balance is assumed, which does not account for potential depletion or sequestration of soil carbon. Beef production systems can also be analyzed, but this version of the model has not been as extensively evaluated. To illustrate the use of the model, three production systems were evaluated and compared: full confinement, winter confinement with summer pasture, and animals outdoors year-round with summer pasture. With the total farm emission expressed per cow, differences across systems were small but the year-round outdoor system emitted the least GHG. When the carbon footprints of the systems were compared, the footprint of the outdoor pastured dairy was about 50% greater than that of the full confinement dairy. DairyGHG provides a relatively simple tool for estimating net GHG emissions from farms and evaluating management effects on these emissions and the overall carbon footprint. |
