Can Consumer Choices Impact the Environmental Footprint of our Food Systems?

Introduction

It is estimated that the human world population will exceed nine billion by 2050 (United Nations, 2019), raising a global concern over food security. Increasing consumption of animal protein has been suggested as one of the sustainable strategies to address food security, as it is a rich source of the most common limiting essential amino acids (FAO, 2013; Gorissen and Witard, 2018; Van Vliet et al., 2015), as well as vitamin B12 (Obersby et al., 2013), calcium (Magkos et al., 2020), and heme-iron (Haider et al., 2018). In addition, animal protein is typically more digestible and the amino acids more bioavailable due to the absence of the anti-nutritional factors that are often associated with plant-based proteins (Phillips, 2012; Tang et al., 2009; Wilkinson et al., 2007).

Despite these benefits, the potential of animal agriculture to feed a growing population has been questioned over environmental concerns, including land and water use, as well as greenhouse gas (GHG) and ammonia (NH3) emissions. Improved production efficiency within the livestock sector has led to a decrease in the environmental footprint of many livestock commodities. For example, over a 30-yr time period (1981–2011), Canadian beef producers reduced GHG emissions (/kg carcass) by 15% (Legesse et al., 2016), ammonia emissions by 17% (Legesse et al., 2018a), water use by 20% (Legesse et al., 2018b), while using 24% less land (Legesse et al., 2016). Similarly, fat- and protein-corrected milk (FPCM; kg/cow/yr) production increased by 43%, whereas enteric methane (kg CO2/kg FPCM) and total emission intensity (kg CO2/kg FPCM) from the dairy sector decreased by 22% (Jayasundara and Wagner-Riddle, 2014) over a 20-yr period (1991–2011). In addition, the egg industry reported a 57% decrease in industry total GHG emissions, with energy, land, and water use declining by 10%, 71%, and 53%, respectively (Pelletier, 2018). Lower emission intensities in all livestock sectors have occurred as a result of improvements in animal productivity (reproductive efficiency, weaning weight, and carcass weight), genetic selection, disease management, precision feed formulation and feeding technologies, crop yields (barley grain, barley silage, corn grain, and corn silage), and irrigation efficiency (Legesse et al., 2016; Legesse et al., 2018b).

In the cattle industry, productivity-enhancing technologies (PETs) including implants, estrous suppressants, ionophores and beta-adrenergic agonists, have been used to improve growth and feed efficiency (Dunshea, 2016; Neumeier and Mitleohner, 2013; Smith et al., 2020). As described in a review by Aboagye et al. (2021), PETs can impact cost of production for producers, diet choice and cost of food for consumers, as well as the environmental sustainability of our food systems.

Hormonal Implants

Natural reproductive hormones (estradiol, testosterone, and progesterone) and synthetic derivatives including zearalenone, trenbolone acetate (TBA), and melengestrol acetate (MGA) are used in beef production (Galbraith, 2002). Most of these hormones are administered as implant pellets, placed between the skin and the cartilage of the ear (Davis and Belk, 2018) where they are released into the bloodstream over a 60-120 d period (Stewart, 2013). The only exception is MGA which is administered in the feed. Implants have been shown to increase weight gain and carcass weight by 0.27 kg/d and 21.4 kg, respectively (Reinhardt and Wagner, 2014). Backgrounded and finished cattle fed grain diets gained 10% - 30% more than those that were not implanted (Reinhardt and Wagner, 2014; Platter et al, 2003; Partridge, 2011).

Implants can also increase dry matter (DM) intake and feed efficiency by 5% - 10% and 5% - 15%, respectively (Dunshea et al., 2016). Growth hormones can be used at any stage of the production system from suckling through to weaning, backgrounding, and finishing phases, with the type selected dictated by the stage of production (Zobell et al., 2000). Therefore, an individual animal can receive several implants throughout its lifetime.

Ionophores

Ionophores, including monensin, lasalocid, salinomycin, and laidlomycin, are usually included in the diet of confined cattle during the growing and finishing phases. They are carboxylic polyether antibiotics (Rokka et al., 2013) that select against gram-positive bacteria and rumen protozoa (Ranga Niroshan Appuhamy et al., 2013) thereby promoting the formation of propionate in the rumen. Propionate acts as an electron sink and decreases the availability of electrons for the reduction of carbon dioxide to methane by methanogens (Ranga Niroshan Appuhamy et al., 2013). Ionophores can also reduce DM intake (DMI) by 3.0% - 8%, while maintaining weight gain, resulting in 6% - 8% improvement in feed efficiency (Duffield et al., 2012; Goodrich et al., 1984; Spires et al., 1990)

Beta-Adrenergic

Agonists Beta-adrenergic agonists, which include ractopamine chloride (RC), zilpaterol chloride (ZC) (Centner et al., 2014), and lubabegron mimic adrenalin resulting in the redirection of nutrients from digestive organs into muscle tissue. This leads to an increase in muscle mass at the expense of fat synthesis (Neumeier and Mitloehner, 2013). Ractopamine chloride has been shown to increase weight gain by 0.24 kg/d and carcass weight by 7.3 kg, while ZC increased weight gain by 0.15 kg/d, and final body and carcass weights by 8 kg and 15 kg, respectively (Lean et al., 2014). Ractopamine chloride is typically fed for 28-42 days (Davis and Belk, 2018; Smith et al., 2019) with no withdrawal, while ZC is fed for 20-40 days with a three-day withdrawal prior to slaughter (Smith et al., 2019). Lubabegron was registered on the basis of its ability to reduce NH3 emissions as it increases nitrogen retention and reduces the amount of urea in urine that can be converted to NH3 (Government of Canada, 2021).

Impact of PET Use

Cost of Production

In the United States, the cost of gain in PET-treated cattle during the finishing phase was reduced by 6% - 25% compared to PET-free cattle when feed was priced at US$ 0.26/kg DM, and the cost of gain was US$ 2.20/kg (Thompson et al., 2016; Maxwell et al., 2015; Smith et al., 2020). In addition to reduced cost of production, producers that use PETs do not incur the costs associated with the record keeping and auditing procedures that may be required in “natural” production programs (Smith et al., 2020).

Consumer Choice

Despite demonstrated benefits in productivity, some consumers perceive that PETs may have negative impacts including environment, food safety, and animal welfare concerns (Godfray et al., 2018; Jeong et al., 2010; Nachman and Smith, 2015). A study conducted by Nielsen Global Health and Ingredient–Sentiment Survey (2016) with 30,000 online consumers reported that over 50% of participants from Europe (65%), Latin America (59%), Asia-Pacific (59%), Africa/Middle East (55%), and North America (54%) would avoid animal products containing hormones or antibiotics. These online responses may be biased, as they are based on claimed behavior rather than direct measurement of product preferences from consumers, wholesalers, hotels, restaurants, and grocery stores. Therefore, they may not represent market trends in terms of types and volumes of animal products sold. Further, although online survey methodology allows for global outreach, it includes responses only from internet users and not the entire population.

The percentage of Texas beef producers enrolled in “natural” programs (i.e., raised without antibiotics and additional hormones) increased from 35% to 43%, while those enrolled in “raised without added hormone” programs increased from 5.2% to 23.8% from 2010 to 2018 (Odde et al., 2019). However, it is important to note that the demand for beef and beef products raised without the routine use of PET and labeled as “raised without antibiotics”, “raised without added hormones”, “natural” (raised without antibiotics and additional hormones), “organic” (raised without antibiotics and additional hormones and feed that was not genetically engineered or produced using synthetic fertilizer), or “100% grass-fed” comprises a small portion of the total market (Beef Checkoff, 2020; Cheung et al., 2017; United States Department of Agriculture, 2021).

Food Cost

Use of PETs has also been shown to reduce the cost of US beef from US $15.50 to 13.80/kg (Olvera, 2016). In the US, labeling beef as “raised without antibiotics or hormones” increased its price by as much as US$ 6.56/kg, a 47% premium over conventionally-produced beef US $14.06/kg (White and Brady, 2014). Canadian research regarding consumers’ willingness to pay premiums for beef products labeled as “use of antibiotics with no hormones”, “responsible use of antibiotics with hormones”, “responsible use of antibiotics with no hormones”, and “no antibiotics and no hormones” demonstrated premiums/kg of beef product of $12.13, $14.22, $21.08, and $30.07 CAD, respectively (Norris, 2020). Willingness to pay more for “natural” or “organic” beef has been reported elsewhere (Lewis et al., 2017; Colella and Ortega, 2017) however, other attributes such as price may largely determine purchasing behavior (Tait et al., 2018). It is also important to note that as premiums do not always makes their way back to the producer, there can be a lack of an incentive to produce “raised without” beef products.

Environmental Impact

The impact of PETs on the environmental footprint, including GHG and NH3 emissions, as well as land and water use, has been conducted by several researchers. Recently, Boonstra et al. (2023) modeled these environmental indices in feedlot cattle. The GHG and NH₃ emissions from implanted heifers (HTBA), MGA heifers (HMGA), implanted steers (STBA) and ractopaminetreated steers (SRAC) were 3.8%, 3.0%, 10.1%, and 8.5% lower and 4.3%, 2.9%, 7.4%, and 7.6% lower, respectively, than the respective control cattle. The land required to produce feed was also reduced by 6.6%, 4.8%, 9.9%, and 10.9%, while water use was reduced by 6.4%, 4.8%, 10.1%, and 11.1% for HTBA, HMGA, STBA, and SRAC, respectively. This modelling study clearly demonstrates that conventional beef production systems have a lower environmental footprint than nonconventional systems.

Given consumer interest in “free-from” and natural additives, Aboagye et al. (2022) demonstrated that the use of conventional PETs (implants, MGA, monensin, tylosin, and βAA) can effectively improve the sustainability of beef production by decreasing GHG and NH3 emissions while decreasing land and water use. Use of natural feed additives did not improve cattle performance and increased the environmental footprint of beef production. Although some natural feed additives appeared to decrease GHG and NH3 emissions, as well as land and water use at a constant DOF, cattle productivity and carcass performance were not improved. Adjusting the slaughter weights to the same weight of cattle administered conventional PETs increased the number of days required to finish cattle that received natural feed additives. Therefore, it was evident that the removal of the conventional technologies (implants, MGA, monensin, tylosin, and βAA) and the use of natural feed additives could increase the environmental footprint of beef production. However, positive additive effects on either animal performance or the environment were seen with the administration of conventional PETs (i.e., MGA, tylosin, monensin, and βAA) with essential oils. Therefore, removal of these conventional technologies or a replacement with natural feed additives may impact productivity as well as the environmental sustainability of feedlot cattle production. Further research on the additive effects of the conventional treatments and essential oils is needed.

Collectively, these studies demonstrate a positive environmental impact associated with the use of PETs. Variation in the magnitude of response may be attributed to differences in methodology (LCA analysis vs. animal trials) and management practices including type, timing, and duration of PET use, number of days on feed, and final carcass weight. Although the benefits of PET use including increased production efficiency, reduced the cost of production, and consumer cost, concerns about the potential negative impact of PETs on wildlife habitats, animal welfare, and food safety are evident. These concerns persist although studies in Canada have shown that PET residues rapidly degrade in the environment or are at concentrations that are below the threshold to impact aquatic life (Challis et al., 2021). Given these misconceptions, it is difficult to convey the benefits of PETs to consumers in a soundbite of information, such as a label claim.

Consumer Engagement

The complexity of our agro-ecosystems has made it difficult to evaluate and compare overall production system sustainability based on multiple environmental indicators, and to effectively communicate that information to consumers. As described in a review by Ominski et al. (2021), we have refined our ability to measure complex environmental metrics such as biodiversity and carbon sequestration, but do not have a mutually agreed-upon public vision for their valuation. This impacts our ability to alter management strategies as public priorities change more quickly than food production systems. More recently, the intersect between diet, environment, and health has further widened and complicated sustainability assessments, as it is impossible to develop a single metric to assess the numerous factors that contribute to a sustainable diet. Therefore, although sustainable production systems and diets are important for human and environmental well-being, there is no “silver bullet” approach to define the trade-offs that exist between environmental health, human health, economic feasibility, and cultural preferences of the Canadian consumer. Social media has facilitated global communication regarding the impact of food production systems on the environment, often without acknowledging the differences in management practices that exist in various regions of the world (e.g., Amazon rainforest and Prairie grasslands). The production sector, as well as retailers and conservation groups, must continue to monitor and report nationally/regionally appropriate sustainability metrics to garner and maintain consumer confidence. As stakeholders in the livestock sector, we are eager to share our knowledge with consumers. How we capture their attention is an ever-allusive challenge. Engagement between industry stakeholders and consumers in Canada has been facilitated through public programing including that offered by Agriculture in the Classroom (https://aitc.mb.ca/), the Farm Food Discovery Centre (FFDC; https://umanitoba.ca/farm-and-food-discovery-centre/) at the University of Manitoba, as well as national initiatives including the Canadian Centre for Food Integrity (CCFI; https://www.foodintegrity.ca/) whose mandate is to coordinate research, dialogue, resources, and training in Canada’s food system. Surveys conducted by CCFI have demonstrated that farmers, researchers/scientists and the agricultural sector rank the highest for public trust and transparency (CCFI, 2023).

Farm revenue streams in the future may consist of: i) commodity sales (livestock, grain); ii) adoption of management practices to reduce GHG emissions (carbon trading); iii) adoption of management practices to enhance other environmental goods and services (biodiversity); and iv) compensation for time spent engaging with the general public through in-person events (Discover the Farm, Ag in the City) and social media.

There is an immediate need for all sectors of food chain -- dieticians, environmental/agroecosystem scientists, policymakers and producers -- to work together to inform public education and policy initiatives using science-based information to ensure optimal use of natural resources, nutritional adequacy, improved human health, and the environmental sustainability of Canadian diets (Ominski et al., 2021). Multi- and trans-disciplinary collaboration is required to understand the complexity of food production and consumption and to develop and implement creative solutions to address environmental challenges. However, as we support consumers in their quest to make informed choices regarding diet, we must be mindful that there is room in the marketplace for a range of food productions systems. Designing these systems so they are regionally-aligned to specific environments will be key to ensuring their sustainability.

Conclusions

Productivity-enhancing technologies have been shown to improve production efficiency and therefore play a role in contributing to the global sustainability of beef production. However, the effects of PETs on addressing consumer concerns regarding the environmental footprint of beef production are offset by perceptions about the impact of PET on the environment, animal welfare, and food safety. The beef industry can realize premiums from domestic and international demand by adopting management practices that do not use PETs to raise cattle and sustain beef production. Nevertheless, because PETs reduce the cost of production, the potential for economic viability will depend on the magnitude of the premiums realized. For consumers, withdrawal of PETs can have negative implications for the environment and increase the retail price of beef, potentially impacting low-income consumers who would benefit the most from the favorable nutrient profile of beef. Globally, scientific data regarding the effects of removing PETs on environmental inputs and outputs are limited to Canada and the US. Furthermore, there is an increasing effort to identify feed additives, which increase production and decrease the environmental impacts of beef production. As global data on conventional and other non-conventional feed additives become available through further research, it is imperative to provide stakeholders including consumers, governments, and producers with comprehensive science-based evidence regarding the environmental impacts of traditional and emerging PETs.

Presented at the 2024 Animal Nutrition Conference of Canada. For information on the next edition, click here.