Factory Farms, Adverse Effects of

Updated About encyclopedia.com content Print Article Share Article
views updated

Factory Farms, Adverse Effects of


Factory farms (which are also sometimes called confined animal feeding operations) are enclosed or open-air facilities that house thousands to tens of thousands of poultry, swine, or cattle. The intent of factory farms is to reduce the costs of raising high numbers of the poultry or livestock by reducing the space necessary to contain them, and making it easier for handlers to care and feed the particular species.

Factory farming by a few corporations has grown in popularity, displacing individually operated farms. For example, in the United States the number of pig farms has decreased from one million in the mid-1960s to about 115,000 in 2002. In 2002, of the 95 million pigs slaughtered in the United States for food production, 80 million were raised on factory farms. In the state of North Carolina, the 7 to 10 million hogs present at any one time on factory farms outnumbers the state’s human population of about 6.5 million.

Aside from the disadvantages that factory farms have brought to family-run farms, and the ethical concerns regarding the welfare of the birds and animals raised in these cramped environments, factory farms have a number of environmental consequences.

Housing of large numbers of poultry or livestock in a small space requires a large amount of available incoming clean water, which can stress local surface and groundwater supplies. Furthermore, a factory farm generates huge amounts of waste; a factory farm housing 10,000 hogs can produce as much waste in one day as a community of 25,000 people. The accidental discharge of the massive amount of waste that is usually collected into large holding ponds due to leakage, rupture of the lining of the pond, or storm-related destruction of the pond can contaminate surrounding water sources. Such incidents are not rare events. Dozens of spills have been documented by the U.S. Environmental Protection Agency (EPA) since the 1970s. As well, the stench from open-air holding ponds can reduce air quality downwind, and can be a source of airborne heavy metals and toxic compounds such as hydrogen sulfide.

In 2008, an environmental issue that is growing in recognition is that the crowded conditions of factory farms can make it easier for diseases to become established and spread. A prime example is the avian influenza (also known as the bird flu), which was first apparent in 1996–1997 on poultry farms in China and Hong Kong. It was initially a disease transmitted from bird-to-bird. However, the virus has evolved in at least a few cases to be capable of direct person-to-person transmission. The common practice of providing low concentrations of antibiotics to livestock as a means of increasing their weight gain has been proven to generate resistant types of bacteria that are also capable of causing disease in animals as well as in humans.

Historical Background and Scientific Foundations

Factory farms have their origins in the advances that occurred during the late nineteenth and early twentieth centuries. Then, the development of farm machinery, mass production of synthetic fertilizers (which made raising of more crops to feed more animals possible), discovery of feed supplements such as vitamins, and the construction of more dependable and rapid transportation between rural farms and growing urban markets stimulated farm expansion.

The discovery of antibiotics in the mid-twentieth century and the development of effective poultry and livestock vaccines made it possible to raise large numbers of animals indoors, since diseases could be controlled.

In 1947, a new agriculture act in Britain that was in part aimed at reducing the need for meat importation financially rewarded farmers for establishing large herds or flocks. Similar legislation in the United States encouraged the growth of farms and, combined with the growth of urban populations and automation, made large farms an attractive business opportunity for corporations.

The entry of corporations into agriculture drove the creation of factory farms. In the 1930s, almost one-quarter of Americans worked in an agriculture-related business. By the first years of the twenty-first century, less than 2% of Americans identified themselves as farmers.

Aside from these and other social issues, which include the welfare of poultry and animals raised on factory farms, such facilities have a number of adverse environmental consequences. A major problem is the amount of waste that is produced. According to the U.S. Department of Agriculture, the waste produced by domestic livestock (of which about 80% are raised on factory farms) exceeds 60 million tons. This amount represents about five tons for every American, and is 130 times the volume of human waste produced every year, according to the EPA. Typically, the waste is stored in lagoons that can be over seven acres in size. Although some waste lagoons are covered, most are open to the air. The lagoons are required to be lined with a watertight barrier. However, leakage or collapse of the earthen walls of lagoons can occur. In 1999, for example, North Carolina was struck by Hurricane Dennis and Hurricane Floyd within one week. The second hurricane led to widespread flooding and the collapse of the walls of factory farm lagoons that had been damaged by Hurricane


AQUIFER: Rock, soil, or sand underground formation that is able to hold and/or transmit water.

AVIAN INFLUENZA: Also known as bird flu, it is a respiratory disease caused by the H5N1 virus that is thought to have originated in Asian poultry factory farms. The disease, which is lethal when passed from bird-to-bird, is evolving to be capable of person-to-person transmission.

HOLDING POND: A reservoir used to hold polluted or sediment-laden water until it can be treated or recycled.

Dennis. One spill alone released 25 million gallons of feces-laden water into New River, killing an estimated 8 to 10 million fish.

EPA estimates that waste from chicken, hog, and cattle factory farms has polluted 35,000 mi (56,325 km) of waterways in 22 U.S. states and has leached into the ground and contaminated groundwater in seventeen states.

Noxious chemicals including arsenic and copper, bacteria, and viruses are also present in the feces of poultry and livestock. Even if present in a very small amount in an individual animal, in the huge quantities of waste that are produced in a factory farm, correspondingly huge amounts of the chemicals and microbes are present. These can be released into soil and water. The U.S.

Centers for Disease Control and Prevention (CDC) has identified a variety of chemical and microbial pollutants in the wastewater from factory farms. The release of chemicals such as ammonia, phosphorus, and nitrogen can deplete oxygen from the water, which can be another cause of fish death.

The environment of a factory farm can also pose a health hazard to workers. The air in the building can contain noxious chemicals and particles. Breathing the air is a hazard; the CDC has chronicled cases of lung disease in farm factory workers. Some of the maladies can persist for a long time. In addition, because a factory farm can be a breeding ground for infectious diseases due to crowded conditions, compromised health of the poultry or livestock, and use of antibiotics (which can select for the development of antibiotic resistance in bacteria), workers are at risk of becoming infected with the disease-causing bacteria and viruses. Bacteria and viruses are small and light enough to become airborne, and can stay suspended in the farm building. As a result, the microbes can be directly inhaled.

Impacts and Issues

The crowded conditions of a factory farm and the use of antibiotics that are present in concentrations that do not kill bacteria, drive the evolution of bacteria that are resistant to the antibiotics used. The antibiotic-resistant varieties will become dominant over time because of the continuing presence of antibiotics.

For those opposed to factory farming, the specter of antibiotic resistance is especially worrisome for poultry operations, since poultry naturally harbor Salmonella and Campylobacter, two types of bacteria that can cause food poisoning in people. Indeed, Campylobacter sickens at least 2.5 million Americans each year, making it the most common cause of food-related illness in the United States. Studies from the CDC and other institutions have demonstrated that about 20% of broiler chickens raised in the United States are contaminated with Salmonella and 80% are contaminated with Campylobacter. The knowledge that disease-causing bacteria are routinely present in high numbers in an environment that is selecting far more disease-hardy varieties is a concern.

As well, viruses are in an ideal situation to acquire new genetic material that enables them to become capable of causing disease. Avian influenza arose in just this way. Once the virus spread beyond farms to the wider world, continuing change of the virus equipped it to be capable of person-to-person transmission. As of March 2008, although the resulting number of confirmed human cases is only 371, according to the World Health Organization (WHO), over 60% of the infections have resulted in death. The high mortality rate is a concern to agencies including WHO and CDC, who concede that a global epidemic of the human form of avian influenza is assured.

The philosophy of economy that has driven the formation of factory farms has also been reflected in the use of cheap and artificial food. In the United Kingdom, this practice contributed to the emergence of bovine spongiform encephalopathy (BSE, also commonly known as mad cow disease) in cattle, which is linked to the emergence of a variant form of Creutzfeld-Jacob disease in humans.

See Also Aquifers; Fish Farming; Groundwater Quality; Surface Water; Water Pollution



Centner, Terence J. Empty Pastures: Confined Animals and the Transformation of the Rural Landscape. Champaign: University of Illinois Press, 2004.

Johnsen, Carolyn. Raising a Stink: The Struggle over Factory Hog Farms in Nebraska. Winnipeg, Manitoba, Canada: Bison Books, 2003.

Brian D. Hoyle