The Impact of Consuming Animals

Demand for meat, dairy, eggs, and other animal products is increasing worldwide as urbanization, higher incomes, and the pursuit of higher living standards lead to shifts in consumption patterns. In the US, public attitudes and social norms have been shaped by agribusiness marketing strategies and public policies that encourage the consumption of industrial animal products. In many segments of society, animal consumption is assumed to be necessary. However, arguments against consuming animals challenge these common assumptions, citing negative impacts on animal welfare, climate change, health, and food justice.


Animal consumption means eating the body parts of animals or using products made from their bodies. Eating eggs and dairy products also constitutes animal consumption since these industries send animals to be slaughtered once they are no longer productive. Animal skin is used for leather clothing and other accessories, and in 2016 290 million cows were killed globally every year for leather products. Animal products are also consumed as additives to many types of food. For example, bone char is often used to bleach sugar; gelatin made from animal collagen is found in many products like candies, broths, and sauces; some beer contains an ingredient sourced from fish bladders; and milk and whey powders are added to a variety of processed and packaged foods.

Animal consumption is not just confined to humans—animals kept as pets also consume a significant portion of animal products. Over 76 million dogs and 58 million cats live in US households, consuming diets that heavily feature meat. Commercial pet foods contain animal derivatives or byproducts from animals slaughtered in industrial agriculture. Byproducts include products that people do not usually consume, like livers, kidneys, and lungs, as well as animals who have died in transit or on farms. Male chicks, considered byproducts of the egg industry, are also used in pet foods. The rendering industry processes byproducts into proteins, fats, minerals, meat, bone, and feather meal.[1]

Many rendered products are used to feed animals raised in industrial agriculture. In intensively confined operations like feedlots, animals are given compound feed intended to promote rapid growth. Many of its ingredients come from slaughtered animals, including meat, bone, and feather meal; eggshells; whole chickens; dried waste or chicken litter; animal fats and oils; fish, shrimp, or crab meal and oil; and dried milk or whey.[2] In the aquaculture industry, wild-caught small pelagic fish like herring and sardines are fed to farmed fish in the form of fish meal and oil. Terrestrial animal byproducts such as bone meal are also fed to farmed fish.[3]


Nonconsumptive forms of animal use include animals used for entertainment, physical labor, and biomedical experiments. Captive wild animals, including lions, tigers, bears, and elephants, are used in circuses, petting zoos, and roadside zoos in the US. Cows and horses are used in rodeos, and many species of animals are used in the film and television industries. Horse racing and greyhound racing are also examples of nonconsumptive uses of animals.

Draft animals are used for physical labor like plowing, hauling, and transportation. While the rise of industrial agriculture in the US coincided with a global decline in draft animal use,[4] in parts of the world where subsistence farming is common, many farmers still depend on draft animals to meet farm labor needs.[5]

Over 790,000 cats, dogs, guinea pigs, nonhuman primates, rabbits, sheep, and other animals are used in laboratory experiments annually in the US. This number is in addition to an estimated 111 million mice and rats.[6] Animal tissues are also used in cell cultures, wound treatments, organ transplants, and heart valve replacements.


Animal consumption varies with cultural norms and the availability of animals. Differences also exist between urban and rural and industrial and subsistence settings. However, industrialized agriculture has promoted high-output systems that bring cheap, commercially produced animal products to local markets worldwide. The most commonly consumed terrestrial animals are chickens, pigs, sheep, and cows. Animal agriculture kills 68 billion chickens and 1.5 billion pigs, 500 million sheep, and 300 million cows every year.

Buffalo, goats, ducks, rabbits, horses, turkeys, and other domestic terrestrial animals are also consumed. In some areas of the world, wild animals such as bats, snakes, and monkeys are also routinely consumed, either as a luxury[7] or to supplement subsistence diets.[8] In the US and other industrialized nations, many people also hunt and eat wild animals like deer, elk, and pheasant.

Aquatic animals are consumed worldwide in high numbers and may be caught from the wild or raised in intensive aquaculture pens on land or in the sea. In 2020, 97 million tons of fish were slaughtered. Because aquatic species are measured by weight, it is only possible to estimate the number of individuals this vast harvest represents, but estimates place the annual total between 0.79–2.3 trillion fish. Other sea life, including crabs, lobsters, and shrimp, are also eaten. Global seafood consumption has doubled in the past several decades.


Many people understand that animals experience pain and suffering, and there is an increasing awareness among consumers of the cruelties inherent in industrial agriculture. In addition to harming farmed animals, consuming high levels of animal products, particularly from industrial confined animal farming, exacts a heavy toll on the environment.

Given that animal products are not required for human nutrition and continued consumption of industrially farmed animals perpetuates inhumane and unsustainable conditions, there are several ethical arguments against consuming animals. These arguments hinge upon two questions: Is it wrong in principle to kill animals for humans to eat? And does it continue to be wrong if raising and slaughtering animals is carried out humanely? Ethical frameworks regarding the consumption of animals seek to balance an animal’s fundamental desire to live with the human’s interest in eating them.


In The Case for Animal Rights in 1983, philosopher Tom Regan introduced an ethical framework based on the equal inherent value of animal and human life. In other words, animals have a distinct moral value independent of any use that humans may have for them. According to this argument, any form of animal exploitation is unacceptable, and animals must be treated with respect in a way that recognizes their intrinsic value. This line of thought supports ideas of animal rights and efforts to move animals from being considered as things to being considered as persons, thus ensuring them greater moral and legal protection.

The rights-based argument opposes eating animals because raising and slaughtering animals for consumption treats them as objects to be traded for human pleasure. Therefore, more humane measures of husbandry and slaughter do not suffice under the rights argument, as the fundamental unethical act is treating animals as renewable resources rather than as individual beings with value unrelated to how they can benefit humans.


Utilitarianism’s guiding principle states that actions should promote happiness for the greatest number of people, and actions that cause harm should be avoided. Eighteenth-century philosopher Jeremy Bentham, who famously said about animals, “The question is not, ‘Can they reason?’ … but, ‘Can they suffer?’” was a proponent of utilitarianism and argued that consideration of happiness and harm should apply to animals, given their capacity for suffering.

Nearly two centuries after Bentham, philosopher Peter Singer explicitly connected utilitarianism and avoidance of animal consumption. Singer argued that utilitarians ought to forgo animal consumption due to the harms of industrial animal agriculture, including animal suffering, worker injustices, and damage to the environment.[9]


Virtue ethics emphasizes the motivation and character of the individual, positing that a virtuous person would carry out acts based on compassion and kindness. Therefore, once an individual is aware of the cruelties inflicted on animals by consuming them, the individual would no longer participate in those acts. Virtue ethics provides a critique of utilitarianism, which allows for harmful acts to be committed toward animals if they contribute to general happiness and instead questions the attitudes that underlie animal use. Virtue ethics places importance on people’s motives and character. In ascribing value to honesty, compassion, and fairness, this approach asserts that virtuous people will make the decision not to consume animals because of the suffering it causes.


An estimated 99% of animals raised for food in the US live in intensive farms. Large-scale industrial agriculture results in many harms to animals, humans, and the environment.


Consuming animals raised on industrial farms contributes to climate change and the negative consequences of global warming—drought, severe storms, wildfires, and biodiversity loss. Large-scale animal agriculture produces high levels of greenhouse gases (GHGs), including 30% of anthropogenic methane.[10] Overall, animal agriculture contributes at least 15.6% of all greenhouse gas emissions, making it one of the top sectors of concern, along with fossil fuels and transportation, for causing environmental destruction.[11]

GHGs are emitted during production of fertilizers and pesticides and the farming of industrial animal feed crops such as corn and soy. The worldwide demand for meat, driven by industrial agriculture, has led to extensive deforestation to clear land for soybean farming and cattle ranching. Deforestation exacerbates climate change by emitting carbon during burning and by decreasing the capture of carbon from the atmosphere by healthy forests, resulting in 5.3 billion metric tons of carbon dioxide being released annually.[12]


Most consumed animals are raised in intensive industrial operations. These operations focus on producing high volumes of animal products and are the reason many people in the US and the Global North can eat meat and other animal products on a daily basis. But this easy access to animal products comes with high animal welfare costs. Animals raised in industrial agriculture experience intense confinement in stalls, pens, crates, and cages that restrict movement and prevent normal social relationships. Animals are overcrowded, leading to aggression and repetitive stress behaviors.

To control negative behaviors and enable extreme confinement, industrial animal farming operations subject animals to tail and beak amputations, dehorning, and castration, typically without anesthesia or pain management. Farmed animals are viewed as commodities, and any that do not maximize value for the industry are deemed “waste” animals. Male chicks born into the egg industry are routinely killed just after hatching and sent into the rendering industry, and male calves born into the dairy industry are confined to small crates and slaughtered for veal at less than five months old.[13]


Animal agriculture uses 77% of agricultural land worldwide and profoundly affects local environments. Confined farmed animals produce around 500 million tons of manure and waste annually, which they store in large manure lagoons. This waste leaches into soil and waterways near intensive animal facilities and contaminates surrounding environments.[14]

Intensive farming and overgrazing cause desertification of arid and semi-arid areas of land and loss of vegetation. Overuse of nitrogen-based fertilizers in the production of animal feed crops pollutes waterways and disrupts soil health and nutrient cycling. The industrial practices of plowing, annual monocropping, and heavy fertilizer and pesticide use have resulted in significant damage to topsoil, contributing to the gradual degradation and desertification of nearly one-third of the world’s land.


Animal consumption comes with a large water footprint. Globally, agriculture uses 92% of freshwater resources, and nearly one-third of agricultural water consumption is related to the production of farmed animals.[15] Drinking water for farmed animals only amounts to 1% of the water footprint of animal agriculture. The majority of water consumption happens during farming of irrigation-dependent feed crops and during contamination by nutrients and pollutants lost by runoff from industrial farms. Nutrient runoff and pollution generated by manure lagoons contaminate water, requiring large amounts of clean water to dilute residues to safe levels.

Cattle raised for beef use the most water, followed by sheep, pigs, and goats. Beef has an average water footprint 20 times larger than cereal and starchy vegetable crops, and the water footprint per gram of protein in beef is 6 times larger than that of beans. Even the egg industry, which has one of the smaller water footprints of industrial agriculture, is still 1.5 times larger than beans.[16]


Industrial agriculture hurts small farmers and disrupts rural communities. Industrial farms pollute the environments of rural communities with manure and waste, increase irritants in the air, and emit noxious odors that severely disrupt the quality of life for the surrounding community.[17]

Local and federal policies offer preferential tax credits and economic incentives to large-scale operations, excluding many small and mid-size farms from economic support. With mechanized harvesting and reliance on synthetic fertilizers, pesticides, and herbicides, industrial farms can consistently deliver large quantities of commodity products. The high output and market dominance of these operations leave many small-scale farmers unable to compete. Farms that formerly grew crops for local consumption experience economic pressure to grow animal feed like soy for industrial animal farms. Smaller farms that face difficulties may end up losing their land or becoming subcontractors for larger operations, resulting in a loss of economic independence and increasing income uncertainty for farmers.

When industrial animal farming begins in a community, large amounts of animal products can be produced with few workers, and local employment often suffers. For jobs that remain, industrial farms employ immigrants and other vulnerable populations with little bargaining power, exploiting their labor for low pay in hazardous working conditions. Nearly 75% of workers in industrial animal farms suffer from acute bronchitis and other ailments from exposure to airborne pollutants, including hydrogen sulfide, ammonia, methane, and dust. Workers in slaughterhouses experience repetitive stress injuries and high incidence of serious bodily harm from fast-moving slaughter lines. Since the start of the COVID-19 pandemic, these essential workers have also faced particularly high risk of virus exposure in the workplace.


There are many reasons to reduce or avoid consumption of animals and their byproducts—the cruelty of industrial animal agriculture, the environmental effects of climate change and land degradation, and the negative social and economic effects on rural communities, farmers, and workers. Conventional industrial agriculture and its harmful practices can be replaced with plant-based foods that are more environmentally friendly and minimally processed and that do not require consumption or exploitation of animals. Sustainable agriculture based on locally-produced plant crops offers an alternative vision of farming that can offer better outcomes for all stakeholders in the food system, including farming communities, consumers, animals, and the planet.

[1] D. L. Meeker and J. L. Meisinger, “Rendered Ingredients Significantly Influence Sustainability, Quality, and Safety of Pet Food,” Journal of Animal Science 93, no. 3 (March 2015): 835–847,

[2] Amy R. Sapkota et al., “What Do We Feed to Food-Production Animals? A Review of Animal Feed Ingredients and Their Potential Impacts on Human Health,” Environmental Health Perspectives 115, no. 5 (May 2007),

[3] Tharindu Bandara, “Alternative Feed Ingredients in Aquaculture: Opportunities and Challenges,” Journal of Entomology and Zoology Studies 6, no. 2 (2018): 3087–3094,

[4] George B. Ellenberg, “Debating Farm power: Draft Animals, Tractors, and the United States Department of Agriculture,” Agricultural History 74, no. 2 (Spring 2000): 545–568,

[5] Ashulata Netam and Payal Jaiswal, “Role of Animal Power in the Field of Agriculture,” International Journal of Avian and Wildlife Biology 3, no. 1 (2018): 62–63,

[6] Larry Carbone, “Estimating Mouse and Rat Use in American Laboratories by Extrapolation from Animal Welfare Act-Regulated Species,” Scientific Reports, 11 (2021),

[7] Robin Naidoo, Daniel Bergin, and Jan Vertefeuille, “Socio-Demographic Correlates of Wildlife Consumption During Early Stages of the COVID-19 Pandemic,” Nature, Ecology and Evolution 5 (2021): 1361–1366,

[8] Julia L. van Velden et al., “Bushmeat Hunting and Consumption Is a Pervasive Issue in African Savannahs: Insights from Four Protected Areas in Malawi,” Biodiversity and Conservation 29 (2020): 1443–1464,

[9] Peter Singer, “Utilitarianism and Vegetarianism,” Philosophy and Public Affairs 9, no. 4 (Summer 1980): 325–337,

[10] Marielle Saunois et al., “The Global Methane Budget 2000–2017,” Earth System Science Data 12, no. 3 (July 15, 2020): 1561–1623,

[11] Matthew N. Hayek and Scot M. Miller, “Underestimates of Methane from Intensively Raised Animals Could Undermine Goals of Sustainable Development,” Environmental Research Letters 16, no. 6 (June 2021): 063006,

[12] Nancy L. Harris et al., “Global Maps of Twenty-First Century Forest Carbon Fluxes,” Nature Climate Change 11, no. 3 (March 2021): 234–40,

[13] Joyce D’Silva, “Adverse Impact of Industrial Animal Agriculture on the Health and Welfare of Farmed Animals,” Integrative Zoology 1 (2006): 53–58,

[14] Koneswaran and Nierenberg, “Global Farm Animal Production and Global Warming,”

[15] P.W. Gerbens-Leenes, M.M. Mekonnen, and A.Y. Hoekstra, “The Water Footprint of Poultry, Pork and Beef: A Comparative Study in Different Countries and Production Systems,” Water Resources and Industry 1–2 (March 2013): 25–36,

[16] Mesfin M. Mekonnen and Arjen Y. Hoekstra, “A Global Assessment of the Water Footprint of Farm Animal Products,” Ecosystems 15 (2012): 401–415,

[17] Carrie Hribar, “Understanding Concentrated Animal Feeding Operations and their Impact on Communities,” (National Association of Local Boards of Health, 2010),

About the author

Stray Dog Institute

To cultivate dignity, justice, and sustainability in the food system, Stray Dog Institute provides nonprofit allies with funding, strategic research, and opportunities for collaboration. Together, we hope to build a more compassionate world for people, animals, and the environment.

About the Author

To cultivate dignity, justice, and sustainability in the food system, Stray Dog Institute provides nonprofit allies with funding, strategic research, and opportunities for collaboration. Together, we hope to build a more compassionate world for people, animals, and the environment.

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