Stunning
Encyclopedia
Stunning is the process of rendering animals immobile or unconscious, without killing the animal, prior to their being slaughtered
Animal slaughter
Slaughter is the term used to describe the killing and butchering of animals, usually for food. Commonly it refers to killing and butchering of domestic livestock ....

 for food.

History

This process has been common for centuries in the case of cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...

, which were poleaxed
Bardiche
A bardiche or berdiche is a type of glaive polearm known in the 16th and 17th centuries in Eastern Europe and Russia. Ultimately a descendant of the medieval sparth , the bardiche proper appears after 1500, but there are numerous medieval manuscripts that depict very similar weapons beginning ca....

 prior to being bled out. In the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 and Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 more widely the development of stunning technologies occurred largely in the first half of the twentieth century.

Prior to humane slaughter pistols and electric stunners, pig
Pig
A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...

s, sheep and other animals (including cattle) were simply struck while fully conscious. The belief that this was unnecessarily cruel and painful to the animal being slaughtered led to the compulsory adoption of stunning methods in many countries. The Humane Slaughter Act of 1933 in Britain, for example, was specifically conceived not only to make stunning compulsory, but moreover to make modern methods, such as the captive bolt pistol
Captive bolt pistol
A captive bolt pistol is a device used for stunning animals prior to slaughter....

 and electric tongs, the means by which it was achieved. The wording of the 1933 act specifically outlaws the poleaxe. The period is marked by the development of various innovations in slaughterhouse technologies, not all of them particularly long-lasting.

United States regulation

Stunning is regulated by the provisions of the Humane Methods of Slaughter Act
Humane Slaughter Act
The Humane Slaughter Act, or the Humane Methods of Livestock Slaughter Act, is a United States federal law designed to protect livestock during slaughter. It was passed in 1958...

 (7 U.S.C. 1901), which the Food Safety and Inspection Service
Food Safety and Inspection Service
The Food Safety and Inspection Service , an agency of the United States Department of Agriculture , is the public health agency responsible for ensuring that the nation's commercial supply of meat, poultry, and egg products is safe, wholesome, and correctly labeled and packaged...

 (FSIS) is mandated to uphold under the Federal Meat Inspection Act
Meat Inspection Act
The Federal Meat Inspection Act of 1906 was a United States Congress Act that worked to prevent adulterated or misbranded meat and meat products from being sold as food and to ensure that meat and meat products are slaughtered and processed under sanitary conditions. These requirements also apply...

 (21 U.S.C. 603 (b)). No similar provision exists in the Poultry Products Inspection Act of 1957
Poultry Products Inspection Act of 1957
The Poultry Products Inspection Act of 1957 requires USDA’s Food Safety and Inspection Service to inspect all domesticated birds when slaughtered and processed into products for human consumption. By regulation, FSIS has defined domesticated birds as chickens, turkeys, ducks, geese, and guinea...

 (21 U.S.C. 451 et seq.). After confirmation of the first U.S. BSE
Bovine spongiform encephalopathy
Bovine spongiform encephalopathy , commonly known as mad-cow disease, is a fatal neurodegenerative disease in cattle that causes a spongy degeneration in the brain and spinal cord. BSE has a long incubation period, about 30 months to 8 years, usually affecting adult cattle at a peak age onset of...

 case, FSIS issued regulations (69 FR 1887, January 12, 2004) prohibiting the use of the most widely used stunning device (air-injection captive bolt stun gun) because the compressed air (in contrast to the blank cartridge-driven or non-penetrating captive bolt) has been shown to force pieces of brain and other central nervous system (CNS) tissue into the bloodstream. Cattle blood is processed primarily for use as a protein supplement in animal feeds and milk replacer for calves, and could potentially transmit BSE if it contained specified risk materials (SRMs include brain and CNS tissue).

Modern methods

In modern slaughterhouses a variety of slaughter methods are used on livestock. Methods include:
  • Electrical stunning
  • Gas stunning
  • Percussive stunning

Electrical stunning

Electrical stunning is done by sending an electrical current through the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

 and/or heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

 of the animal before slaughter. Current passing through the brain induces an immediate but non-fatal general convulsion
Convulsion
A convulsion is a medical condition where body muscles contract and relax rapidly and repeatedly, resulting in an uncontrolled shaking of the body. Because a convulsion is often a symptom of an epileptic seizure, the term convulsion is sometimes used as a synonym for seizure...

 that produces unconsciousness
Unconsciousness
Unconsciousness is the condition of being not conscious—in a mental state that involves complete or near-complete lack of responsiveness to people and other environmental stimuli. Being in a comatose state or coma is a type of unconsciousness. Fainting due to a drop in blood pressure and a...

. Current passing through the heart produces an immediate cardiac arrest
Cardiac arrest
Cardiac arrest, is the cessation of normal circulation of the blood due to failure of the heart to contract effectively...

 that also leads shortly to unconsciousness and death. It is a controversial subject however. With chickens for example, overstunning leads to bone fractures and/or electrocution which prevents bleeding of the animal. This negatively affects the quality of the meat, and therefore understunning is an attractive practice for slaughterhouses.

In the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

, for example, the law states that poultry must be stunned for 4 seconds minimum with an average current of 100 mA, which leads to systematic understunning.

Gas stunning

With gas stunning animals are exposed to a mixture of breathing gases (carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 for example, but historically carbon monoxide
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...

 was used) that produce unconsciousness or death through hypoxia
Hypoxia (medical)
Hypoxia, or hypoxiation, is a pathological condition in which the body as a whole or a region of the body is deprived of adequate oxygen supply. Variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise...

 or asphyxia
Asphyxia
Asphyxia or asphyxiation is a condition of severely deficient supply of oxygen to the body that arises from being unable to breathe normally. An example of asphyxia is choking. Asphyxia causes generalized hypoxia, which primarily affects the tissues and organs...

. The process is not instantaneous.

Percussive stunning

With percussive stunning, a device which hits the animal on the head, with or without penetration, is employed. Such devices, such as the captive bolt pistol
Captive bolt pistol
A captive bolt pistol is a device used for stunning animals prior to slaughter....

, can be either pneumatic, or powder-actuated. Percussive stunning produces immediate unconsciousness through brain trauma.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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