Industry Initiatives for Environmental Sustainability – a Role for Everyone

This webinar introduces current and future industry-based initiatives for environmental sustainability in the livestock and poultry sector, and how Livestock and Poultry Environmental Learning Community learners can play a critical role in their region. This presentation was originally broadcast on September 17, 2021. Continue reading “Industry Initiatives for Environmental Sustainability – a Role for Everyone”

Do Growth Enhancers Affect the Carbon Footprint of Pork Production?

green stylized pig logoIn swine production, maximizing growth rate while minimizing inputs (efficiency) is a top aim of most farmers. This helps an operation become more profitable, but it also has positive environmental benefits in that the amount of water, feed, or energy needed to produce each pound of pork is reduced. This results in fewer greenhouse gases emitted per pound of pork. (For more information on the relationship between efficiency and carbon footprint in animal agriculture see this Animal Frontiers article).

One particular growth enhancer used by pig farms is ractopamine. This is not an antibiotic, but it alters animal metabolism so that pigs produce more lean tissue (muscle) and less fat. For more on this feed additive, see this Texas A&M fact sheet).

A Comparison of Environmental Footprint With and Without Ractopamine

The image below shows a comparison of the same farm system with and without ractopamine. The results are estimated carbon, water, and land footprints as well as economic costs. The numbers were generated by the Pig Production Environmental Footprint Calculator.

The slide shows a smaller carbon footprint; -37,076 lbs of carbon dioxide equivalents per year when using ractopamine. This farm used 953,754 less gallons of water/year with the growth enhancer and required 14 less acres of land to support the farm. The economic implications (using prices from 2015) were a $11,477 advantage with ractopamine.

slide showing a comparison in carbon, water, land, and economic footprint for a farm with and without ractopamine as a growth enhancer

Slide credit: Dr. Rick Ulrich, University of Arkansas.

Are There Other Ways To Improve Growth Besides Ractopamine?

While growth enhances are a proven way to improve efficiency, there are other research-proven recommendations when making management choices to improve growth rate:

  • Phase feeding – diets change due to changing energy, protein, and other nutritional requirements are different as the animal grows
  • Balancing for specific amino acids (and not just crude protein) for each phase
  • Maintaining a clean environment
  • If in a building, keeping temperature in the optimum range

Management choices also impact health status and biosecurity protocols are used to prevent the presence of specific diseases.  In the past, antibiotics could be added to feed or water at low levels to enhance growth rate, but the concern over the proliferation of antibiotic-resistant bacteria resulted in the new policies to only utilize antibiotics to treat (rather than prevent) disease in food animals. The inclusion of antibiotics deemed medically important is being eliminated (federal rules took effect October, 2015 and the policy is in full effect at the end of 2016) for growth-promoting purposes. (For more, see this newsletter from the National Pork Producers explaining the rules to their members).

For More Information


Author: Amy Carroll, University of Arkansas

This information is part of the program “Integrated Resource Management Tool to Mitigate the Carbon Footprint of Swine Produced In the U.S.,” and is supported by Agriculture and Food Research Initiative Competitive Grant no. 2011-68002-30208 from the USDA National Institute of Food and Agriculture. Project website.

What Is an Environmental Foot Print? (Ecological Footprint)

green stylized pig logoThe Cambridge dictionary defines environmental footprint as:

the effect that a person, company, activity, etc. has on the environment, for example the amount of natural resources that they use and the amount of harmful gases that they produce

Also referred to as an ecological footprint, this is a measure that attempts to consider multiple impacts of an activity rather than focus on a single one. In relation to the swine industry, this foot print takes into account the results of carbon, water, land and air footprints of pig farming.

Related: Evaluating the environmental footprint of pork production

How do you bring all of these different pieces together? In 2011, the U.S. National Pork Board and many land grant researchers launched a project to develop a science-based decision tool called Pig Production Environmental Footprint Calculator (PPEFC). The PPEFC has the ability to calculate (estimate) impact to greenhouse gas emissions, costs, land use, and water consumption across the pork production chain, including feed formulation and crop production. The combined analysis of all of these factors allows identification of potential ecologically and economically feasible production practices for pork producers.

One of the pieces of this project is developing an environmental footprint, cost, and nutrient database of the US animal feed ingredients and integrating it with the calculator. The calculator is built upon cradle-to-farm gate life-cycle assessment (LCA) of pork production combined with the US National Resource Council (NRC) swine nutrient requirements models (NRC 2012), farm operation inputs, and animal feed database. Farm operation inputs include: barn characteristics, utilities, manure management, dead animal disposal, and farm operation costs. For a description of the inputs, visit this conference presentation at LCA Foods 2014.

Additional Information

Factsheets: What is a water footprint? | What is a land footprint? | What is a carbon footprint?

Pig Production Environmental Footprint Calculator (National Pork Board).

Animal agriculture and:


Author: Amy Carroll, University of Arkansas

Reviewers: Jill Heemstra, University of Nebraska; Karl Vandevender, University of Arkansas

This information is part of the program “Integrated Resource Management Tool to Mitigate the Carbon Footprint of Swine Produced In the U.S.,” and is supported by Agriculture and Food Research Initiative Competitive Grant no. 2011-68002-30208 from the USDA National Institute of Food and Agriculture. Project website.

Carbon Footprint, Life Cycle Assessment and the Pork Industry

green stylized pig logoAnimal agriculture in the U.S. contributes approximately 3.5% of all man-made greenhouse gases (GHGs). If you look at pork production, it accounts for just 0.34% of all emissions. (Source: U.S. EPA Greenhouse Gas Inventory released April, 2015).

When you total up all the GHG emissions from a particular activity or process, it is called a carbon footprint. The procedure used to decide which GHG emissions are included in this total is a life-cycle assessment (LCA).

What Is a Carbon Footprint and How Is It Used?

A carbon footprint gives you a snapshot in time of the GHGs produced by the activity or process being evaluated. The number generated is especially useful for comparing different processes or different times.

Some reasons a farm, company, or industry would calculate a carbon footprint include:

  • Identifying “hot spots” in the system to prioritize areas where reductions can be made
  • Creating a baseline measure for comparing over time
  • Looking at “what-if” scenarios and comparing different options to see how each affects GHG emissions

What Goes Into a Life Cycle Analysis?

In order to be able to compare carbon footprints of different farms or different industries, the life-cycle analysis (LCA) needs to use the same parameters. To do this, many people rely upon standardized procedures such as those created by the International Organization for Standardization.

For the pork industry, the pork supply chain is broadly divided into eight stages:

  • feed production;
  • live animal production;
  • delivery to processor;
  • processing;
  • packaging;
  • distribution;
  • retail;
  • consumption/disposal.

The most important thing to remember is that if you compare two or more carbon footprints to each other, the LCA used needs to be the same. If you try to compare footprints generated using different LCAs, you will not get a true comparison.

For more information

Authors: Jill Heemstra, Nebraska Extension and Rick Fields, University of Arkansas


This information is part of the program “Integrated Resource Management Tool to Mitigate the Carbon Footprint of Swine Produced In the U.S.,” and is supported by Agriculture and Food Research Initiative Competitive Grant no. 2011-68002-30208 from the USDA National Institute of Food and Agriculture. Project website.

Do We Know the Carbon Footprint of the Pork Industry?

green stylized pig logoA carbon footprint is a total of all the greenhouse gas emissions (GHG) from a process or industry. A life cycle assessment (LCA) is the process used to figure out what GHG emissions will be included in the footprint. More technically, it is systematic way of looking at a product’s complete life cycle and calculating a “footprint”.  In addition to carbon footprints, there are efforts to calculate land, water, and other environmental footprints.

Below are highlights from several different reports that looked at the carbon footprint of the pork industry on a national and international scale. A comparison between different ways to raise pigs was also highlighted.

Snapshot of the Present Time

On a national scale, a report on the National Life Cycle Carbon Footprint Study for Production of Swine in the U.S. was conducted and published in 2011.

The report concluded that the carbon footprint to prepare and consume a 4 oz serving of pork was ~2.5 lbs of carbon dioxide equivalents. Figure 1 (below) from that report shows the relative breakdown of the industry’s estimated greenhouse gas emissions:

  • Live animal production made up 62.1% of the emissions. That is further broken down and presented in second column (right).
  • Processing – 5.6%
  • Retail – 7.54%
  • Consumption – 23.5% including refrigeration, cooking, and methane from food waste in landfill
  • Packaging (1.3%);

Life cycle assessment of pork production in the U.S.

Comparison Over 50 Years of Production

Another example of an industry-wide analysis, this one comparing over time, is a “50-year comparison of the carbon footprint of the U.S. swine herd 1959 – 2009” (29 pp; PDF). The pork industry overall emits more total greenhouse gases than 50 years ago, but actually emits much less per pound of pork produced because of improvements in efficiency.

From that publication:

The U.S. swine industry produces pigs far more efficiently today (2009) than in 1959. The number of hogs marketed has increased 29% (87.6 million in 1959 to 112.6 million in 2009 after removing market hogs imported directly to harvest) from a breeding herd that is 39% smaller. The efficiency gain is even more impressive when measured against the total dressed carcass weight harvested. Dressed carcass yield leaving the farm has nearly doubled in 50 years from 12.1 billion pounds to 22.8 billion pounds. This increase in productivity has resulted in an increase of 2,231 pounds (2.5x) of carcass harvested annually per sow – year. Today, it takes only five hogs (breeding and market) to produce the same amount of pork that  required eight hogs in 1959.

Comparing Different Ways of Raising Pigs

An example of an LCA that looks at different types of systems is “Life-cycle assessment of commodity and niche swine operations“. (informal Q&A and journal article both available). From the journal article (bottom of page 5):

High-profitability operations have consistently lower impacts compared to low-profitability operations for both commodity and deep-bedded niche piglet production.

Global Assessment from Backyard to Industrial Systems

On an international scale, the report “Greenhouse gas emissions from pig and chicken supply chains” was published in 2013. This study looked at all scales of farms from backyard pigs to industrial production (large confinement operations). Over the entire scale, they estimated that the carbon footprint of pork for every kg (~2.2 lbs) of pig carcass weight has an emissions intensity of 6.1 kg of carbon dioxide equivalent.

This report found that backyard systems, especially in some parts of the world, have low emissions, largely due to by-product or “second-grade” feeds. Industrial pig systems tended to have more emissions intensity than backyard systems, with the emissions from liquid/slurry manure management systems being a big reason. From the conclusion of the report:

When drawing any conclusions about scope for improvement, the following points should be borne in mind: (a)differences in emission intensity may reflect differences in production systems that have arisen over time to enable the system to perform better within a given context, e.g. to make them more profitable, or resilient; (b) focusing on a single measure of efficiency (in this case GHG emissions per kg of output) can lead to positive and negative side effects on, for instance, biodiversity, water quality and animal welfare; (c) reducing GHG emissions is not the only objective producers need to satisfy, as they also need to respond to changing economic and physical conditions.

How Do Carbon Footprints Compare?

It is very important to note that when looking at data and numbers generated from different reports like these, the carbon footprints are difficult to compare unless they use the same LCA. Presenting carbon footprints from different LCA’s is an “apples to oranges” comparison. Only when the same LCA is used, can they be an “apples to apples” comparison.

Additional Information


Authors: Amy Carroll, University of Arkansas and Jill Heemstra, University of Nebraska

This information is part of the program “Integrated Resource Management Tool to Mitigate the Carbon Footprint of Swine Produced In the U.S.,” and is supported by Agriculture and Food Research Initiative Competitive Grant no. 2011-68002-30208 from the USDA National Institute of Food and Agriculture. Project website.

Greenhouse Gas Emissions from Livestock & Poultry

Agriculture is both a source and sink for greenhouse gases (GHG). A source is a net contribution to the atmosphere, while a sink is a net withdrawal of greenhouse gases.  In the United States, agriculture is a relatively small contributor, with approximately 8% of the total greenhouse gas emissions, as seen below.  Most agricultural emissions originate from soil management, enteric fermentation (the ruminant digestion process that produces methane), energy use, and manure management.  The primary greenhouse gases related to agriculture are carbon dioxide, methane, and nitrous oxide. Within animal production, the largest emissions are from beef followed by dairy, and largely dominated by the methane produced in during cattle digestion.

U.S. GHG Inventory

U.S. greenhouse gas inventory with electricity distributed to economic sectors (EPA, 2013) 

Ag Sources of GHGs

U.S. agricultural greenhouse gas sources (Adapted from Archibeque, S. et al., 2012)

Greenhouse gas emissions from livestock in 2008 (USDA, 2011)

Soil Management

Excess nitrogen in agriculture systems can be converted to nitrous oxide through the nitrification-denitrification process. Nitrous oxide is a very potent greenhouse gas, with 310 times greater global warming potential than carbon dioxide.  Nitrous oxide can be produced in soils following fertilizer application (both synthetic and organic).

As crops grow, photosynthesis removes carbon dioxide from the atmosphere and stores it in the plants and soil life. Soil and plant respiration adds carbon dioxide back to the atmosphere when microbes or plants breakdown molecules to produce energy.  Respiration is an essential part of growth and maintenance for most life on earth. This repeats with each growth, harvest, and decay cycle, therefore, feedstuffs and foods are generally considered to be carbon “neutral.”

Some carbon dioxide is stored in soils for long periods of time.  The processes that result in carbon accumulation are called carbon sinks or carbon sequestration.  Crop production and grazing management practices influence the soil’s ability to be a net source or sink for greenhouse gases.  Managing soils in ways that increase organic matter levels can increase the accumulation (sink) of soil carbon for many years.


The next largest portion of livestock greenhouse gas emissions is from methane produced during enteric fermentation in ruminants – a natural part of ruminant digestion where microbes in the first of four stomachs, the rumen, break down feed and produce methane as a by-product. The methane is released  primarily through belching.

As with plants, animals respire carbon dioxide, but also store some in their bodies, so they too are considered a neutral source of atmospheric carbon dioxide.

Manure Management

A similar microbial process to enteric fermentation leads to methane production from stored manure.  Anytime the manure sits for more than a couple days in an anaerobic (without oxygen) environment, methane will likely be produced.  Methane can be generated in the animal housing, manure storage, and during manure application. Additionally, small amounts of methane is produced from manure deposited on grazing lands.

Nitrous oxide is also produced from manure storage surfaces, during land application, and from manure in bedded packs & lots.

Other sources

There are many smaller sources of greenhouse gases on farms. Combustion engines exaust carbon dioxide from fossil fuel (previously stored carbon) powered vehicles and equipment.  Manufacturing of farm inputs, including fuel, electricity, machinery, fertilizer, pesticides, seeds, plastics, and building materials, also results in emissions.

To learn more about how farm emissions are determined and see species specific examples, see the Carbon Footprint resources.

To learn about how to reduce on-farm emissions through mitigation technology and management options, see the Reducing Emissions resources.

 Additional Resources

Additional Animal Agriculture and Climate Change Resources

Author: Crystal A. Powers, UNL