Reducing the Costs and Environmental Footprint of Pig Diets with the Experimental Optimum Synthetic Amino Acid Inclusion

Why Look at Reducing Crude Protein in Pig Diets

Nitrogen (N2) compounds from swine feces and urine are oxidized and reduced by soil and air, whereas some N2 is released into the atmosphere as nitrous oxide (N2O). Research has demonstrated that reducing crude protein (CP) and maximizing synthetic amino acids (SAA) in swine diets can reduce N2 excretion. Thus, there is strong push for more sustainable production of soy or replacement with other protein sources.

The preliminary cost and environmental evaluation showed that pig diets with higher amounts of SAAs have higher cost, climate change impact (CCI), and water depletion (WD) than the typical US diet defined. This is due to the increased amounts of corn in a diet. Thus, a list of alternative energy and protein feed ingredients were tested in WUFFDA with the goal to replace corn and further reduce the amount of soybean meal in pig diets.

What did we do? 

Windows-based User Friendly Feed Formulation (WUFFDA) linear models were used to formulate single-objective least cost and least environmental footprint pig. Control diet is a typical soybean-corn formulation which was used as a baseline to evaluate cost and environmental footprint of an alternate diet. The test diet is a reduced crude protein diet with max 0.75% added Lysine-HCL in nursery and max 0.56 % added Lysine-HCL grower-finisher phases. We also added the US pig industry top 80 most used feed ingredients to the WUFFDA. Nutrient characteristics, inclusion limits, environmental footprint, and cost data for feed ingredients were obtained from the US Animal Feed Database and incorporated into WUFFDA models.

What have we learned? 

It was found that reduction in cost of a diet formulation can be achieved by omitting the use of milk whey powder (nursery phase). Replacing corn with wheat middlings could reduce cost and CCI. CCI can be reduced by use of corn gluten meal, and corn gluten feed (grow phases).

Future Plans 

The projected diets will be further investigated for nutrient constraints, validated through PPEC, and Simapro 8.1. life cycle assessment (LCA) model as well as with other experts such as nutritionists and economists. The projected diets will be will be available in the Pig Production Environmental Calculator (PPEC).


Jasmina Burek, Research Associate, University of Arkansas

Greg Thoma, Jennie Popp, Charles Maxwell, Rick Ulrich

Additional information 

Pig Production Environmental Calculator:…

Life-Cycle Assessment Modeling for the Pork Industry:

National Pork Board (2015) Carbon Footprint of Pork Production Calculator – Pork Checkoff.

Pesti G, Thomson E, Bakalli R, et al. (2004) Windows User-Friendly Feed Formulation (WUFFF DA) Version1.02.

PRé Consultants (2014) SimaPro 8.3. 4555022.


This research is part of the program “Climate Change Mitigation and Adaptation in Agriculture,” and is supported by Agriculture and Food Research Initiative Competitive Grant no. 2011-68002-30208 from the USDA National Institute of Food and Agriculture.

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