Can feeding pigs less crude protein reduce their carbon footprint? Does it also affect growth and performance?

green stylized pig logoFeeding less crude protein in pig diets can reduce the carbon footprint of that farm, within limits.  Pigs require amino acids (the building blocks of protein) and different protein sources contain different amounts of essential amino acids.

Feed manufactures have begun to make feed grade amino acids (AA) which allow nutritionists and farmers to balance a diet more precisely and feed less crude protein. In turn, this reduces the amount excess nitrogen excreted in the manure (protein contains a great deal of nitrogen). Research has shown that less nitrogen in manure leads to less emissions of gas like ammonia and the greenhouse gas nitrous oxide. Nitrous oxide is nearly 300 times more powerful than carbon dioxide in terms of its ability to trap heat in the atmosphere.

Growth and performance of pigs is not negatively affected when the diet is appropriately balanced for nutrient needs. Meat quality is improved when reducing crude protein in pig diets. Bottom line: this is a highly recommended practice for pork producers and many farmers utilize at least one amino acid (lysine is the most common) in their rations already.

For more information:

  • Research project examining the use of feed grade AA’s to reduce crude protein in swine diets and whether farmers could use more AA’s than is the current industry norm. They concluded that several limiting AAs can be supplemented to reduce crude protein without compromising performance when the economic conditions (especially when the price of soybean meal is high) are favorable to this practice.
  • Principles of balancing swine diets – gives an expanded discussion on AA and other important aspects related to the challenge of formulating pig diets that are precise (reduce waste and excess nutrients as much as possible) and still support performance and profitability.
  • Evaluating the environmental footprint of pork production examines several aspects of raising pigs that are being examined to discover practices to reduce environmental impact of pig farms.

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


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: