During the June 2011 World Pork Expo, the National Pork Board released the Live Swine Carbon Footprint Calculator. The calculator was developed to provide swine producers a user-friendly tool that estimates the amount of greenhouse gases (GHG) released from their production site. While there is no right or wrong answer contained in the report, the Pork Board suggests the calculator be used to establish a current benchmark level of greenhouse gases (GHG) emissions. Once a farm’s benchmark is established, additional calculations can then be used to estimate possible reductions in GHG as a result of improved management and production practices. Reductions in GHG are possible through improved feed efficiency, reduced energy requirements and changes in manure handling practices.

The National Air Quality Site Assessment Tool (NAQSAT) is another useful tool for determining opportunities to reduce farm GHG emissions with output that complements the output from the Live Swine Carbon Footprint Calculator. For more information on NAQSAT and a link to the online tool see the article recently posted on the MSU Extension News [click here].

GHGs associated with pork production include carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O). Methane has 24 times and nitrous oxide has 298 times the global warming potential of carbon dioxide. The carbon footprint calculator expresses methane and nitrous oxide global warming potential on a carbon dioxide equivalent (CO2e) basis. The output reports GHG emissions as kg of CO2e per year, per pig and per kg of pig raised. Inputs into the calculator require knowledge of:

• The building dimensions and the insulation R value in both the walls and ceiling
• Diets fed to the pigs in the barn including the number of phases and the percentage of each ingredient contained in each ration. Contract growers will need to collect this information from their contracted farms
• Basic manure handling practices such as type of manure storage, months when manure is hauled, size of loads and average distance to the fields used for manure applications
• The total wattage of the lights used in the barn
• The number of fans in the barn, their CFM (cubic feet per minute) and wattage. The wattage will be on the manufacturer’s label found on the side of the fan motor and the CFM will be on either the fan housing or contained in the manufacturer’s information delivered with the fan
• Estimate of annual fuel usage, including fuel used for manure removal but not feed delivery.
• An estimate of the annual water usage. Tables for estimating annual water use can be found online [click here].

Figure 1 provides an overall summary from the Swine Carbon Footprint Calculator for a sample 2,000-head, deep-pit, finishing barn, selling 5,100 head annually at an average weight of 275lbs and feed efficiency of 2.98lb feed per lb gain. For this sample farm, 68.8 per cent of the estimated 969,405kg (1,068.8 tons) CO2e annually emitted are attributed to feed, 22.9 per cent to manure (methane and nitrous oxide combined) and 7.5 per cent to barn heating and electricity. The high percentage of GHG emissions attributed to feed is directly related to the nitrous oxide losses associated with the growing crops and, to a lesser degree, the fossil fuels required for crop production including the fuels used in the manufacturing of agricultural chemicals and nitrogen fertilizers.

Improving feed efficiency to 2.69 decreased GHG emissions 11.6 per cent to 856,576 kg (944.4 tons) CO2e annually while the break down attributable to feed, manure and barn utilities, 70.1 per cent, 21.2 per cent and 7.7 per cent, respectively, remained relatively the same. Improving feed efficiency provides the dual benefits of reducing GHG associated with feed production and reducing methane and nitrous oxide emissions associated with enteric fermentation and manure management (Nguyen, 2010). The relationship between GHG attributed to feed and GHG attributed to manure remained relatively constant as feed efficiency improved.

Using a feed efficiency of 2.98, the Live Swine Carbon Foot Print Calculator estimated an emission of 1.52kg CO2e per kg live pig. Improving feed efficiency to 2.68 reduced the carbon footprint to 1.35kg CO2e per kg live pig.

The 12 per cent decrease in GHG emissions resulted from improved feed utilisation. Additional gains are possible. Nguyen (2010) compared three scenarios: 1) improved feed efficiency, 2) shortened length of time manure is stored in the barn (to less than 15 days), and 3) improved manure management including utilising manure for energy production prior to using it as a replacement for commercial fertiliser. His model predicted a 49 per cent reduction in GHG emissions if all three areas were improved simultaneously.

The swine carbon footprint calculator software is available free from the National Pork Board. It requires either Windows XP, Vista, 2000 or Windows 7.

The Live Swine Carbon Footprint Calculator was written by Dr Rick Ulrich and Dr Greg Thoma from the University of Arkansas, Dept. of Chemical Engineering.

January 2012