Meat Eaters Guide: Methodology - Environmental Working Group

In contrast to beef, according to this model, post-farmgate emissions comprise more than half all
poultry emissions sources. Processing accounts for about 24 percent of total emissions, followed by
home cooking (17 percent), transport (4 percent), waste disposal (1 percent) and retail energy use
and refrigeration (less than 1 percent).
5. Dairy (Cheese)
Life cycle analyses for milk are based on a high-productivity and average-productivity system in Wisconsin
and a typical Idaho milk production/dairy system. Cheese emissions are calculated based on
milk that is produced on an average-productive Wisconsin dairy farm. Although less than 10 percent
of cheese is imported, and a small portion of that is imported by air, our LCA calculates GHG estimates
for shipped and air freighted imported cheese. Airfreighting cheese increases the overall emissions
by about 50 percent.
a. Key Production and Modeling Details for Wisconsin Dairy
• Herd-replacement rate is approximately 33 percent due to cull loss and mortality.
• Ready-to-calve heifers are used as replacements.
• A typical cow produces about 22,000 lbs. to 28,000 lbs. of milk per year, depending on the
productivity of the system.
• Cows are maintained in a confined feedlot with food rations of mostly hay and grains, supplemented
with soybean meal and minerals. The system produces calves as co-products, which
are sold separately.
• Most material inputs, including all grain and feed supplements, are assumed to be procured
from national sources and transported an average of 1,600 km by semi-trailer trucks. Locally
available inputs (such as hay) are assumed to be transported 300 km by single-unit trucks.
• Herd size and operation size are not available; the input data was provided on a per animal
basis.
• The dairy is assumed to be a confined operation with a liquid/slurry manure management
system.
• 8.89 kg of milk are needed to make 1 kg of hard (cheddar) cheese.
• The yogurt is based on 2 percent milk and the production emissions for yogurt represent all
the emissions from 2 percent milk (i.e., 2 percent milk is the raw ingredient for the yogurt).
• Production of 1 kg of 2 percent yogurt uses 1 kg of 2 percent homogenized/pasteurized milk,
0.0026 kwh of electricity and 0.029 cu-m of natural gas. Bacterial starter cultures are not
included in the calculations because of lack of data and because the impact will likely be negligible.
Environmental Working Group Meat Eaters Guide: Methodology 2011 33