Dr. Jerry Shurson, Professor, Department of Animal Science, University of Minnesota

Now more than ever before, the types and sources of feed ingredients used to formulate, and manufacture swine diets has never been more important. Although cost and economic value of feed ingredients will always be major factors for sourcing feed ingredients, we also need to take into account whether they provide functional characteristics that may improve pig health, assess their relative risk of foreign animal disease transmission if imported from other countries, and their contributions to environmental impacts such as climate change, natural resource use, and carbon footprint of pork production systems. While all these criteria are important, sourcing and using feed ingredients that have reduced negative impact on the environment in swine diets is a rapidly emerging trend in the global feed and pork industry that can have a substantial effect on improving the environmental sustainability of pork production.

Climate change continues to threaten many dimensions of global ecosystems and natural resources which directly affect agriculture and food production. According to the Food and Agriculture Organization of the United Nations, food animal production contributes about 14.5% to total global greenhouse gas (GHG) emissions annually. Beef (35.3%) and dairy (30.1%) cattle contribute over two-thirds of GHG (primarily due to methane emissions) from animal production systems, while swine (9.5%) and poultry (8.7%) contribute the least. A recent summary published by the National Pork Board showed that during the past 55 years, the U.S. pork industry has made significant improvements toward environmental sustainability by reducing land (75.9%), water (25.1%), and energy (7.0%) use, while also reduced carbon emissions per pound of pork produced by about 7.7%. These environmental benefits are significant and were primarily achieved by increasing productivity and efficiency of pork production. However, several U.S. pork industry leaders are striving to further reduce the environmental footprint of their pork production systems to become carbon neutral or carbon negative. While this goal can partially be achieved by using renewable energy resources such as wind, solar, and methane digesters to provide power to the farm, there are additional opportunities that can have greater impact on reducing negative environmental impacts of pork production. Nearly half (46.7%) of GHG emissions from food animal production is a direct result of the types and sources of renewable and non-renewable resources used to produce various feed ingredients, as well as environmental impacts from processing and transport. Therefore, if the U.S. and global pork industry is to make further improvements in achieving environmental sustainability, a major focus should be on sourcing and using low environmental impact feed ingredients in swine diet formulations.

Globally sustainable pork production systems must use diet formulation and precision feeding strategies that improve caloric and nutritional efficiency, minimize renewable and non-renewable resource use, and reduce the impact of climate change on human, animal, plant, and planet health. Life cycle assessment (LCA) of environmental impacts of food production systems has become a widely accepted reference method for guiding decisions and transitioning toward more globally sustainable food production and consumption patterns (LEAP, 2015). In fact, numerous LCA studies have been conducted to estimate the impact of various types of pork production systems on the environment in most major pork production countries, including the U.S. (Lammers et al., 2010a; Lammers, 2011; Pelletier et al., 2010; Stone et al., 2011; 2012; Thoma et al., 2011; Matlock et al., 2014; Eshel et al., 2014). However, unlike the European Union (van der Werf et al., 2005; Uwizeye et al., 2016; Wilfart et al., 2016), only a few LCA studies have evaluated the environmental impact of feed ingredients used in North American swine diets (Lammers et al., 2010b; Mackenzie et al., 2016a,b; Kebreab et al., 2016). In fact, several databases of feed ingredients with LCA indicator estimates have been developed (Table 1), but the types and sources of ingredients included in these databases represent mainly ingredients approved and available for use in the European Union, with a limited number of ingredients that are routinely used U.S. or North America swine diets. As a result, countries in the E.U., especially France, are far more advanced in developing and implementing LCA in formulating low environmental impact swine diets, compared with North America, South America, and Asian countries

The Global Feed LCA Institute (GFLI) is a feed industry initiative to develop a free and publicly available feed LCA database, to support LCAs of livestock products using region specific data and provides benchmarks of feed industry environmental impacts. The database and tool are based on internationally standardized LCA methodology from the Livestock Environmental Assessment Partnership (LEAP, 2015). There are 962 feed ingredients in the GFLI database, with estimates of 18 environmental impact indicators based on economic, energy, and mass allocations Table 2). Because of the limited number of North American produced feed ingredients included in the GFLI database, our University of Minnesota team has initiated new research and education collaborations with pork, feed industry, and academic partners in the U.S. and Europe to develop and help implement LCAs for various U.S. feed ingredients, which need to be added to this database. Accomplishing this goal will enable the U.S. feed and pork industry the opportunity to further reduce environmental impacts of pork production by implementing econutrition diet formulation and feeding programs, while continuing to keep pace with increasing consumer preferences for food products produced using “eco” or low environmental impact production systems.

Among all feed ingredients commonly used in North American swine diets, corn is used in the greatest proportions relative to other ingredients, and consequently, differences in LCA indictors among corn sources can have a significant influence on overall diet environmental impacts. For example, using data from the GFLI database for 6 of the 18 LCA indicators at the farm level, and comparing these indicators among sources of corn produced in Minnesota, U.S. average, Mexico, Brazil, and Canada using economic allocation, there are substantial differences in environmental impacts (Figure 1 and 2). Global warming with or without land use change was lowest for corn produced in Minnesota, followed by the U.S. average and Canada, but was substantially greater for Mexican and Brazilian corn. Considering land use change alone, corn sourced from Mexico and Brazil had much greater impacts on land use change than from Minnesota, U.S. average, or Canada. Similarly, corn sourced from Minnesota had the least impact on water use, fossil resource scarcity, and terrestrial ecotoxicity, while corn sourced from Mexico and Brazil had the greatest negative impact (Figure 2). This simple comparison of the differences in environmental impacts among corn sources shows how this approach can be extremely useful for sourcing low environmental impact feed ingredients.

Soybean meal is another major feed ingredient used in U.S. swine diets, and LCAs of soybean meal originating from Brazil show much greater negative environmental impacts compared with soybean meal produced in the U.S. This has resulted because of extensive and ongoing deforestation of the Amazon in Brazil, and it’s devastating effect on the environment. In fact, consumers in several European countries have created pressure to prevent the feed and food animal industry from importing and using of Brazilian soybean meal in animal feeds. In contrast, the United Soybean Board, American Soybean Association, and the U.S. Soybean Export Council developed and implemented the U.S. Soy Sustainability Assurance Protocol which certifies and ensures that environmentally sustainable production practices are used on the majority of U.S. soybean farms.

Table 1. Comparison of selected characteristics of LCA feed ingredient databases.

 ¹Blend of databases compliant with EC Product Environmental Footprint for energy and transport

Table 2. Environmental impact measures of feed ingredients in the Global Feed LCA Institute database

Figure 1. Comparison of corn sources produced in Minnesota, U.S. average, Mexico, Brazil, and Canada on global warming potential with and without land use change, and land use only at the farm level using economic allocation in life cycle assessments (GFLI Database, 2018)

Figure 2. Comparison of corn sources produced in Minnesota, U.S. average, Mexico, Brazil, and Canada on water use, fossil resource scarcity, and terrestrial ecotoxicity at the farm level using economic allocation in life cycle assessments (GFLI Database, 2018)

However, the ultimate question is “Can the use of low environmental impact feed ingredients in nutritionally adequate, econutrition swine diets support optimal growth performance and carcass quality while also reducing environmental impact?” To answer this question, Francine de Quelen and her colleagues (de Quelen et al., 2020) at INRAE in Saint Gilles, France conducted a recent study to compare the environmental impacts, growth performance, and carcass composition from using 3 different grower-finisher feeding programs. The feeding program that served as the control for comparison, consisted of grower and finisher swine diets that were typical least cost formulations using common ingredients fed on commercial farms in France (Table 3). The second type of feeding program consisted of “ecodiets” (Table 3) that were formulated for low cost, but also for reduced environmental impact at the feed mill (per kg of feed) and at the farm gate (per kg of live weight gain) based on 5 LCA impacts (climate change, acidification, eutrophication, land occupation, and non-renewable and fossil energy demand). The third type of feeding program compared was based on feeding diets that contained feed ingredients locally produced by French farmers to reduce the environmental impact at the feed mill and farm gate due to feed transport (Table 3). The main differences between the conventional diets compared with ecodiets and local diets was that the proportions of high environmental impact ingredients (cereal grains and oilseed meals) were reduced and replaced with greater proportions of lower environmental impact alternative co-products. All diets within each phase were formulated to contain the same net energy, digestible amino acids, and digestible phosphorus to meet the daily requirements for pig growth.

At the feed mill level (impacts per kg of feed), the ecodiets reduced the impact on climate change by 30%, non-renewable and fossil energy demand by 15%, acidification by 20%, eutrophication by 12%, and land occupation impact by 3% compared with the conventional diets (Table 4). Similarly, when comparing the local diet formulations with the conventional diets, climate change impacts, renewable and fossil energy demand, and acidification potential were each reduced by 20%, but eutrophication increased by 3% and land occupation increased by 20% (Table 4). Equally important was the fact that growth performance and carcass characteristics were not affected by feeding program (Table 5), which indicated that feeding ecodiets or local diets are effective strategies for reducing environmental impacts at the farm gate (impacts/kg of weight gain) without compromising productivity or carcass composition. As a result, comparing the environmental impact of feeding the ecodiets with conventional diets at the farm gate (Table 4), substantial reductions occurred in all LCA indicators (climate change = 18%, renewable and fossil energy demand = 15%, acidification = 7%, eutrophication = 7%, and land occupation = 4%). Feeding diets containing local ingredients had less beneficial environment impact, where reductions in climate change (12%) and renewable and fossil energy demand (15%) occurred, but no change in acidification, while increasing eutrophication by 5% and land occupation by 22% (Table 4). These results show that substantial environmental benefits can be achieved by changing the dietary proportions of feed ingredients based on their relative environmental impact, without compromising optimal growth performance and carcass composition.

Table 3. Composition of grower and finisher diets (adapted from de Quelen et al., 2020)

Table 4. Environmental impacts of diets at the feed mill (per kg of feed) and at the farm gate (per kg of live weight gain; adapted from de Quelen et al., 2020)

^a,b,cMeans with different superscript are significantly different between experimental diets ( P < 0.05).

Table 5. Effects of feeding ecodiets and diets containing local ingredients on growth performance and carcass characteristics of growing finishing pigs (adapted from de Quelen et al., 2020)

Conclusions

The environmental impacts of feed ingredients vary substantially among sources and directly affect the environmental sustainability of pork production systems. Using low environmental impact feed ingredients to formulate low cost, nutritionally adequate swine diets to support optimal growth performance and carcass composition can be accomplished if databases of LCAs of all feed ingredients used in the U.S. are available and used by nutritionists to formulate ecodiets in pork production systems.

 References

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