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Intensive pig farming

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Title: Intensive pig farming  
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Intensive pig farming

Intensive pig farming is a subset of pig farming and of Industrial animal agriculture, all of which are types of animal husbandry, in which domestic pigs are raised up to slaughter weight. These operations are known as AFO or CAFO in the U.S. In this system of pig production, grower pigs are housed indoors in group-housing or straw-lined sheds, whilst pregnant sows are housed in sow stalls (gestation crates) or pens and give birth in farrowing crates.

The use of sow stalls for pregnant sows has resulted in lower birth production costs; however, this practice has led to more significant animal welfare concerns. Many of the world’s largest producers of pigs (US, Canada, Denmark, Mexico) use sow stalls, but some nations (e.g., the UK) and some US states (e.g., Florida, Arizona, and California) have banned their use. The European Union has banned the use of gestation crates after the 4th week of pregnancy.[1]


  • Intensive piggeries 1
    • Legislation 1.1
    • Dispute regarding farming methods 1.2
  • Criticism of intensive piggeries 2
    • Sow breeding systems 2.1
    • Effects on traditional rural communities 2.2
    • Waste management and public health concerns 2.3
    • North Carolina 2.4
    • Denmark 2.5
    • New Zealand 2.6
  • See also 3
  • References 4
  • External links 5

Intensive piggeries

Intensive piggeries are generally large warehouse-like buildings or barns. Indoor pig systems allow the pigs' conditions to be monitored, ensuring minimum fatalities and increased productivity. Buildings are ventilated and their temperature regulated. Most domestic pig varieties are susceptible to sunburn and heat stress, and all pigs lack sweat glands and cannot cool themselves. Pigs have a limited tolerance to high temperatures and heat stress can lead to death. Maintaining a more specific temperature within the pig-tolerance range also maximizes growth and growth-to-feed ratio. Indoor piggeries have allowed pig farming to be undertaken in countries or areas with unsuitable climate or soil for outdoor pig raising (e.g., Australia).[2] In an intensive operation, pigs will no longer need access to a wallow (mud), which is their natural cooling mechanism. Intensive piggeries control temperature through ventilation or drip water systems (dropping water to cool the system).

Pigs are naturally omnivorous and are generally fed a combination of grains and protein sources (soybeans, or meat and bone meal). Larger intensive pig farms may be surrounded by farmland where feed-grain crops are grown. Consequently, piggeries are reliant on the grains industry. Pig feed may be bought packaged, in bulk or mixed on-site. The intensive piggery system, where pigs are confined in individual stalls, allows each pig to be allotted a portion of feed. The individual feeding system also facilitates individual medication of pigs through feed. This has more significance to intensive farming methods, as the proximity to other animals enables diseases to spread more rapidly. To prevent disease spreading and encourage growth, drug programs such as vitamins and antibiotics are administered preemptively.

Indoor systems, especially stalls and pens (i.e., ‘dry,’ not straw-lined systems) allow for the easy collection of waste. In an indoor intensive pig farm, manure can be managed through a lagoon system or other waste-management system. However, waste smell remains a problem which is difficult to manage.[3] Pigs in the wild or on open farmland are naturally clean animals.

The way animals are housed in intensive systems varies. Breeding sows will spend the bulk of their time in sow stalls (also called gestation crates) during pregnancy. The use of stalls may be preferred as they facilitate feed management and growth control and prevent pig aggression (e.g., tail biting, ear biting, vulva biting, food stealing). Sows are moved to farrowing crates, with litter, from before farrowing until weaning, to ease management of farrowing and reduce piglet loss from sows lying on them. Dry or open time for sows can be spent in indoor pens or outdoor pens or pastures. Houses should be clean and well ventilated but draught-free.

Piglets can be subjected to castration, tail docking to reduce tail biting, teeth clipping (to reduce injuring their mother's nipples), and earmarking and tattooing for litter identification. Treatments are usually made without pain killers. Weak runts may be slain shortly after birth. Injections with a high availability iron solution often are given, as sow's milk is low in iron. The docking due to tail biting is a common practice in intensive rearing facilities as animals in that environment are more prone to increased levels of aggression and instability.[4]

Piglets are weaned and removed from the sows at between two and five weeks old[5] and placed in sheds, nursery barns or directly to growout barns. Grower pigs – which comprise the bulk of the herd – are usually housed in alternative indoor housing, such as batch pens. Group pens generally require higher stockmanship skills. Such pens will usually not contain straw or other material. Alternatively, a straw-lined shed may house a larger group (i.e., not batched) in age groups. Larger swine operations use slotted floors for waste removal, and deliver bulk feed into feeders in each pen; feed is available ad libitum.

Many countries have introduced laws to regulate treatment of farmed animals. In the US, the federal Humane Slaughter Act[6] requires pigs to be stunned before slaughter, although compliance and enforcement is questioned. There is concern from animal liberation/welfare groups that the laws have not resulted in a prevention of animal suffering and that there are "repeated violations of the Humane Slaughter Act at dozens of slaughterhouses".[7]


Since 2003 EU legislation has:

  • required that pigs be given environmental enrichment, specifically they must have “permanent access to a sufficient quantity of material to enable proper investigation and manipulation activities, such as straw, hay, wood, sawdust, mushroom compost, peat or a mixture of such …”
  • prohibited routine tail docking. Under the legislation tail docking may only be used as a last resort. The law provides that farmers must first take measures to improve the pigs’ conditions and, only where these have failed to prevent tail biting, may they tail dock.[8]

In the US:

  • Nine states have banned the use of gestation crates, with Rhode Island being the most recent as of July 2012.[9]
  • Discharge from CAFOs is regulated by the federal Environmental Protection Agency (EPA). In 2003 the EPA revised the Clean Water Act (CWA) to include permitting requirements and effluent (discharge) limitations for CAFOs. Final AFO/CAFO regulation issued 2008 revised portions of the 2003 EPA regulated under EPA’s National Point Discharge Elimination System (NPDES) permitting program.[10]

Dispute regarding farming methods

Intensive piggeries have been increasingly criticized in preference of free range systems. Such systems usually refer not to a group-pen or shedding system, but to outdoor farming systems. Those that support outdoor systems usually do so on the grounds that they are more animal friendly and allow pigs to experience natural activities (e.g., wallowing in mud, relating to young, rooting soil). Outdoor systems are usually less economically productive due to increased space requirements and higher morbidity, (though, when dealing with the killing of piglets and other groups of swine, the methods are the same.) They also have a range of environmental impacts, such as denitrification of soil[11][12] and erosion. Outdoor pig farming may also have welfare implications, for example, pigs kept outside may get sunburnt and are more susceptible to heat stress than in indoor systems, where air conditioning or similar can be used.[13][14] Outdoor pig farming may also increase the incidence of worms and parasites in pigs.[15][16] Management of these problems depends on local conditions, such as geography, climate, and the availability of skilled staff.

Transition of an indoor production system to an outdoor system may present obstacles. Some breeds of pig commonly used in intensive farming have been selectively bred to suit intensive conditions. Lean pink-pigmented pigs are unsuited for outdoor agriculture, as they suffer sunburn and heat stress. In certain environmental conditions – for example, a temperate climate – outdoor pig farming of these breeds is possible. However, there are many other breeds of pig suited to outdoor rearing, as they have been used in this way for centuries, such as Gloucester Old Spot and Oxford Forest. Following the UK ban of sow stalls, the British Pig Executive indicates that the pig farming industry in the UK has declined.[17] The increase in production costs[18] has led to British pig-products being more expensive than those from other countries, leading to increased imports and the need to position UK pork as a product deserving a price premium.

In the late '90s Grampian Country Foods, then the UK’s largest pig producer, pointed out that pigmeat production costs in the UK were 44 p/kg higher than on the continent. Grampian stated that only 2 p/kg of this was due to the ban on stalls; the majority of the extra costs resulted from the then strength of sterling and the fact that at that time meat and bone meal had been banned in the UK but not on the continent. A study by the Meat and Livestock Commission in 1999, the year that the sow stall ban came into force, found that moving from sow stalls to group housing added just 1.6 pence to the cost of producing 1 kg of pigmeat. French and Dutch studies show that even in the higher welfare group housing systems – ones giving more space and straw – a kg of pigmeat costs less than 2 pence more to produce than in sow stalls.[8]

Criticism of intensive piggeries

Sows are often confined in gestation crates, which usually does not allow the pig to turn around. Confinement farming methods have come under increasing public scrutiny due to animal welfare and environmental concerns.

Sow breeding systems

Organized campaigns by animal activists have focused on the use of the sow stalls, such as the 'gestation crate' (sow stall) and 'farrowing crate'. The sow stall has now been banned in the UK, certain US states, and other European countries, although it remains part of pig production in much of the US and European Union.

Only the sows selected for breeding (i.e., pregnant sows) will spend time in a sow stall. In an intensive system, the sow will be placed in a stall prior to service (mating) and will stay there for at least the start of her pregnancy, when the risk of miscarriage is higher. The length of the sow's gestation is 3 months, 3 weeks, and 3 days. In certain cases, sows may spend this time in the crate. However, a variety of farming systems are used and the time in the crate may vary from 4 weeks to the whole pregnancy.

There is also some criticism of 'farrowing crates'. A farrowing crate houses the sow in one section and her piglets in another. It allows the sow to lie down and roll over to feed her piglets, but keeps her piglets in a separate section. This prevents the large sow from sitting on her piglets and killing them, which is quite common where the sow is not separated from the piglets.[19] Sows are also prevented from being able to move other than between standing and lying. Some models of farrowing crates may allow more space than others, and allow greater interaction between sow and young. Well-designed farrowing pens in which the sow has ample space can be just as effective as crates in preventing piglet mortality.[8] Some crates may also be designed with cost-effectiveness or efficiency in mind and therefore be smaller.

Authoritative industry data indicate that moving from sow stalls to group housing added 2 pence to the cost of producing 1 kg. of pigmeat.[8]

Many English fattening pigs are kept in barren conditions and are routinely tail docked. Since 2003 EU legislation has required pigs to be given environmental enrichment and has banned routine tail docking. However, 80% of UK pigs are tail docked.[8]

As of 2015, it will be illegal to use sow crates on New Zealand pig farms.[20]

Effects on traditional rural communities

Common criticism of intensive piggeries is that they represent a corporatization of the traditional rural lifestyle. Critics feel the rise of intensive piggeries has largely replaced family farming. Between 1982 and 1987 some 21% of Iowa hog farmers went out of business. By 1992, another 12% had gone out of business. In large part, this is because intensive piggeries are more economical than outdoor systems, pen systems, or the sty. In many pork-producing countries (e.g., United States, Canada, Australia, Denmark) the use of intensive piggeries has led to market rationalization and concentration. The New York Times reported that keeping pigs and other animals in "unnaturally overcrowded" environments poses considerable health risks for workers, neighbors, and consumers.[21]

Waste management and public health concerns

Contaminants from animal wastes can enter the environment through pathways such as through leakage of poorly constructed manure lagoons or during major precipitation events resulting in either overflow of lagoons and runoff from recent applications of waste to farm fields, or atmospheric deposition followed by dry or wet fallout. Runoff can leach through permeable soils to vulnerable aquifers that tap ground water sources for human consumption. Runoff of manure can also find its way into surface water such as lakes, streams, and ponds.

Many contaminants are present in livestock wastes, including nutrients, pathogens, veterinary pharmaceuticals and naturally excreted hormones. Improper disposal of animal carcasses and abandoned livestock facilities can also contribute to water quality problems in surrounding areas of CAFOs.

Exposure to waterborne contaminants can result from both recreational use of affected surface water and from ingestion of drinking water derived from either contaminated surface water or ground water. High-Risk populations are generally the very young, the elderly, pregnant women, and immunocompromised individuals. Dermal contact may cause skin, eye, or ear infections. Drinking water exposures to pathogens could occur in vulnerable private wells.[22]

At Varkensproefcentrum Sterksel in the Netherlands, a pig farm has been created that reuses its waste streams. CO² and ammonia from the pig manure are reused to grow algae which in turn are used to feed the pigs.[23]

Another method to reduce the effect on the environment is to switch to other breeds of pig. The enviropig for example is a type of pig with the capability to digest plant phosphorus more efficiently than ordinary pigs.

Nutrient-rich runoff from CAFO's can also contribute to Algal blooms in rivers, lakes and seas. The 2009 HAB (harmful Algal Bloom) event off the coast of Brittany, France is attributed to runoff from an intensive pig farm.[24]

North Carolina

As of 2010, North Carolina houses approximately ten million hogs, most of which are located in the eastern half of the state in industrialized CAFOs or Confined Animal Feeding Operations. This was not the case twenty years ago. The initial horizontal integration and the vertical integration that arose in this industry resulted in numerous issues, including issues of environmental disparity, loss of work, pollution, animal rights, and overall general public health. The most remarkable example of swine CAFO monopoly is found in the United States, where in 2001, 50 producers had control over 70% of total pork production. In 2001, the biggest CAFO had just over 710,000 sows.[25]

Originally, Murphy Family Farms horizontally integrated the North Carolina system. They laid the groundwork for the industry to be vertically integrated. Today the hog industry in North Carolina is led by Smithfield Foods, which has expanded into both nationwide and international production.[26]

The environmental justice problems in North Carolina's agroindustrialization of swine production seem to stem from the history of the coastal region's economy, which has relied heavily on black and low-income populations to supply the necessary agricultural labor. The industry's shift from family-owned hog farms to factory hogging has contributed to the frequent targeting of these areas.[27]

This swine production and pollution that accompanies factory hogging is concentrated in the parts of North Carolina that have the highest disease rates, the least access to medical care, and the greatest need for positive education and economic development.[28] Since hog production has become consolidated in the coastal region of N.C., the high water tables and low-lying flood plains have increased the risk and impact of hog farm pollution. A swine CAFO is made up of three parts: the hog house, the “lagoon,” and the “spray field.” Waste disposal techniques used by small-scale traditional hog farms, like using waste as fertilizer for commercially viable crops, were adopted and expanded for use by CAFOs. Lagoons are supposed to be protected with an impermeable liner, but some do not work properly. This can cause environmental damage, as seen in 1995 when a lagoon burst in North Carolina. This lagoon released 25 million gallons of noxious sludge into North Carolina’s New River and killed approximately eight to ten million fish.[29]

The toxins emitted by the swine CAFOs can produce a variety of symptoms and illnesses ranging from respiratory disorders, headaches, and shortness of breath to hydrogen sulfide poisoning, bronchitis, and asthma. The potential for spray field runoff or lagoon leakage puts nearby residents in danger of contaminated drinking water, which can lead to diseases like samonellosis, giardiasis, Chlamydia, meningitis, crytosporidiosis, worms, and influenza.[30]

Denmark stated that IceNews reported that in 2009 the number of pigs that arrived at slaughterhouses with injuries incurred by planks and chains increased. IceNews cited a Copenhagen Post report saying that increasing abuse "may be caused by the new system, introduced in 2006, which rewards" the rushed loading of animals onto vehicles. Over 2008 and 2009, the number of pig abuse cases in Denmark had increased fivefold.[31]

Sometimes sow stalls are used to restrict the movement of sows during pregnancy. This practice is prohibited for pigs exported to the UK. However, the method was found on some Danish farms by British celebrity chef Jamie Oliver in a television programme for the UK's Channel 4 in 2009.[32][33]

New Zealand

According to Scoop, in 2009 the New Zealand pork industry was "dealt a shameful public relations slap-in-the-face after its former celebrity kingpin, Mike King, outed their farming practices as 'brutal,' 'callous' and 'evil'" on a May episode of New Zealand television show Sunday. King condemned the "appalling treatment" of factory farmed pigs. King observed conditions inside a New Zealand piggery, and saw a dead female pig inside a sow stall, lame and crippled pigs and others that could barely stand, pigs either extremely depressed or highly distressed, pigs with scars and injuries, and a lack of clean drinking water and food.

Sow crate farming should be illegal and we should outlaw it right now. It is absolutely disgusting and I am sorry that I was part of it,
— Mike King, 2009, [34]

See also


  1. ^
  2. ^ Australian pork page on Pig welfare
  3. ^
  4. ^ EFSA. Scientific Opinion of the Panel on Animal Health and Welfare (Question No EFSA-Q-2006-013) Adopted on 06 December 2007 The risks associated with tail biting in pigs and possible means to reduce the need for tail docking considering the different housing and husbandry systems
  5. ^ Revisiting weaning age
  6. ^ US Federal Humane Slaughter Act
  7. ^ Animal Welfare Institute Quarterly – Humane Slaughter Act Resolution Introduced
  8. ^ a b c d e Compassion in World Farming – EFRA Pigs submission 2008
  9. ^ Marcelo, Philip. New R.I. law bans cutting dairy-cow tails, raising pigs and calves in crates Providence Journal, June 21, 2012. Accessed July 31, 2012.
  10. ^
  11. ^ The fate of nitrogen in outdoor pig production
  12. ^ Investigation of carbon and nitrogen cycles in pig farming
  13. ^ Managing Heat Stress in Outdoor pigs
  14. ^ Heat stress index chart for swine producers
  15. ^
  16. ^ Pig Management Control and Prevention
  17. ^ British Pig Executive market update September 2005
  18. ^ "Another Move Away from Pork Crates," Farm Futures, May 8, 2012.
  19. ^ “Piglet Losses,” University of Illinois Extension, Nov. 5, 2003.
  20. ^
  21. ^ Health Risks @ New York
  22. ^ Burkholder JoAnn; Bob Libra, Peter Weyer, Susan Heathcote, Dana Kolpin, Peter S. Thorne, Michael Wichman (2007) mpacts of Waste from Concentrated Animal Feeding Operations on Water Quality. Environ Health Perspectives. 115:308–312.
  23. ^ Pig manure used to grow algae to feed pigs
  24. ^
  25. ^ Swine Production: A Global Perspective
  26. ^
  27. ^
  28. ^ Raine J. Environmental Justice Issues of the North Carolina Swine Industry [Masters thesis]. Durham, NC:Duke University, Nicholas School of the Environment, 1998.
  29. ^ Orlando, Laura. McFarms Go Wild, Dollars and Sense, July/August 1998, cited in Scully, Matthew. Dominion, St. Martin's Griffin, p. 257.
  30. ^
  31. ^ SwineNews @
  32. ^ Christian Coff, David Barling, Michiel Korthals, Thorkild Nielsen, Ethical Traceability and Communicating Food, pp.90–91, Springer, 2008 ISBN 1-4020-8523-0.
  33. ^ DBMC Response to 'Jamie Saves Our Bacon' (Channel 4 – Thursday 29 January 2009) press release from Danish Bacon and Meat Council, January 2009.
  34. ^ Mike King's Investigation @

External links

Government regulation
  • Brief History of CAFO Regulations – from the National Association of State Departments of Agriculture
  • EPA's Guide to CAFO Industry Regulations
  • North Carolina State Government Study on Ammonia Concentration in the Air
Proponent, neutral, and industry-related
  • Journal of Extension, article on case studies of the impact of large scale agriculture
  • US Farm Bureau, Farm and Ranchers association
  • The Pig Site – industry support site with feature articles and news, with an emphasis on intensive farming practices
  • Industry-run site on intensive pig farming
  • Coalition to Support Iowa Farmers
  • USDA food safety
  • Purdue University food science extension
  • Swine Wean-to-Finish Cost-Return Budget, Kansas State University
  • North Carolina Pork Council's Perspective of Hog Farming Industry and the Environment
  • CDC's Informational Links about CAFOs
  • Discussion of Problems and Solutions from Environmental Defense Fund
Criticism of intensive pig farming
  • – the New Zealand group SAFE campaign to end intensive pig farming.
  • Animals Australia's campaign to end pig factory farming featuring James Cromwell
  • Swine Production: A Global Perspective
  • Anti-agricultural FAQs on Factory Farming
  • Compassion in World Farming – Publications – Pig Farming
  • Factory farming pork
  • Husbandry Institute Promoting sustainable, responsible, and ethical animal husbandry
  • [1] Environmental Defense Fund's Overview of Top Hog Farms in NC
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