Stunning is the process of rendering animals immobile or unconscious, with or without killing the animal, when or immediately prior to slaughtering them for food.

Rationale

Within the

European Union The European Union (EU) is a supranational union, supranational political union, political and economic union of Member state of the European Union, member states that are Geography of the European Union, located primarily in Europe. The u ...

, most animals slaughtered for human consumption are killed by cutting major

blood vessel Blood vessels are the tubular structures of a circulatory system that transport blood throughout many Animal, animals’ bodies. Blood vessels transport blood cells, nutrients, and oxygen to most of the Tissue (biology), tissues of a Body (bi ...

s in the

neck The neck is the part of the body in many vertebrates that connects the head to the torso. It supports the weight of the head and protects the nerves that transmit sensory and motor information between the brain and the rest of the body. Addition ...

thorax The thorax (: thoraces or thoraxes) or chest is a part of the anatomy of mammals and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main di ...

so that rapid blood loss occurs. After a certain degree of blood loss has occurred, the animal will become unconscious, and after a greater blood loss

death Death is the end of life; the irreversible cessation of all biological functions that sustain a living organism. Death eventually and inevitably occurs in all organisms. The remains of a former organism normally begin to decompose sh ...

will ensue. From the moment of cutting until the loss of consciousness, the animal experiences

pain Pain is a distressing feeling often caused by intense or damaging Stimulus (physiology), stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sense, sensory and emotional experience associated with, or res ...

, stress, and

fear Fear is an unpleasant emotion that arises in response to perception, perceived dangers or threats. Fear causes physiological and psychological changes. It may produce behavioral reactions such as mounting an aggressive response or fleeing the ...

. Without stunning, the time between cutting through the major blood vessels and insensibility, as deduced from behavioural and

brain The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for ...

response, is up to 20 seconds in

sheep Sheep (: sheep) or domestic sheep (''Ovis aries'') are a domesticated, ruminant mammal typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus '' Ovis'', in everyday usage it almost always refers to d ...

, up to 25 seconds in

pig The pig (''Sus domesticus''), also called swine (: swine) or hog, is an omnivorous, domesticated, even-toed, hoofed mammal. It is named the domestic pig when distinguishing it from other members of the genus '' Sus''. Some authorities cons ...

s, up to 2 minutes in

cattle Cattle (''Bos taurus'') are large, domesticated, bovid ungulates widely kept as livestock. They are prominent modern members of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Mature female cattle are calle ...

, up to 2.5 or more minutes in

poultry Poultry () are domesticated birds kept by humans for the purpose of harvesting animal products such as meat, Eggs as food, eggs or feathers. The practice of animal husbandry, raising poultry is known as poultry farming. These birds are most typ ...

, and sometimes 15 minutes or more in

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

. If one seeks to minimise animal suffering in slaughter, stunning is necessary. The best stunning method depends on the species; the quality of equipment and the adequate training of personnel also influence effectiveness.

History

A primitive form of stunning was used in premodern times in the case of

, which were poleaxed prior to being bled out. However, prior to slaughter pistols and electric stunners,

, and other animals (including cattle) were simply struck while fully conscious. The belief that it was unnecessarily cruel to slaughter an animal against its will eventually led to the compulsory adoption of stunning methods in many countries. One of the first campaigners on the matter was the eminent physician, Benjamin Ward Richardson, who spent many years of his later working life developing more "humane" methods of slaughter. As early as 1853, he designed a lethal chamber that would gas animals to death supposedly painlessly and without their knowledge, and he founded the Model Abattoir Society in 1882 to investigate and campaign for other methods of slaughter. He even experimented with the use of electric current at the

Royal Polytechnic Institution The University of Westminster is a public university based in London, United Kingdom. Founded in 1838 as the Royal Polytechnic Institution, it was the first polytechnic A polytechnic is an educational institution that primarily focuses on vo ...

. The development of stunning technologies occurred largely in the first half of the twentieth century. In 1911, the Council of Justice to Animals (later the Humane Slaughter Association)(HSA) was created to improve the slaughter of livestock and address the killing of unwanted pets. In the early 1920s, the HSA introduced and demonstrated a mechanical stunner, which led to the adoption of stunning by many local authorities." The HSA played a key role in the passage of the Slaughter of Animals Act 1933. This made the mechanical stunning of cows and electrical stunning of pigs compulsory, with the exception of

Jewish Jews (, , ), or the Jewish people, are an ethnoreligious group and nation, originating from the Israelites of History of ancient Israel and Judah, ancient Israel and Judah. They also traditionally adhere to Judaism. Jewish ethnicity, rel ...

and Muslim meat. Modern methods, such as the

captive bolt pistol A captive bolt pistol (also known as a captive bolt gun, a cattle gun, a stunbolt gun, a bolt gun, a stun gun and a stunner) is a device used for the stunning of animals prior to slaughter. A captive bolt pistol is intended to deliver a single ...

and electric tongs were required and the Act's wording specifically outlawed the

poleaxe The poleaxe (also poleax, pollaxe and other similar spellings) is a European polearm that was used by medieval infantry. Etymology Most etymological authorities consider the ''poll''- prefix historically unrelated to "pole", instead meaning " ...

. The period was marked by the development of various innovations in slaughterhouse technologies, not all of them particularly long-lasting.

Modern methods

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

Electrical stunning

Electrical stunning is done by sending an electric current through the

and/or

heart The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrie ...

of the animal before slaughter. Current passing through the brain induces an immediate but non-fatal general

convulsion A convulsion is a medical condition where the body muscles contract and relax rapidly and repeatedly, resulting in uncontrolled shaking. Because epileptic seizures typically include convulsions, the term ''convulsion'' is often used as a synony ...

that produces

unconsciousness Unconsciousness is a state in which a living individual exhibits a complete, or near-complete, inability to maintain an awareness of self and environment or to respond to any human or environmental stimulus. Unconsciousness may occur as the r ...

. Current passing through the heart produces an immediate

cardiac arrest Cardiac arrest (also known as sudden cardiac arrest CA is when the heart suddenly and unexpectedly stops beating. When the heart stops beating, blood cannot properly Circulatory system, circulate around the body and the blood flow to the ...

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

Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

, for example, the law states that poultry must be stunned for 4 seconds minimum with an average current of 100mA, which leads to systematic under stunning. The CrustaStun is a device designed to administer a lethal electric shock to

shellfish Shellfish, in colloquial and fisheries usage, are exoskeleton-bearing Aquatic animal, aquatic invertebrates used as Human food, food, including various species of Mollusca, molluscs, crustaceans, and echinoderms. Although most kinds of shellfish ...

(such as

lobsters Lobsters are malacostracans decapod crustaceans of the family Nephropidae or its synonym Homaridae. They have long bodies with muscular tails and live in crevices or burrows on the sea floor. Three of their five pairs of legs have claws, in ...

crabs Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek), which typically have a very short projecting tail-like abdomen, usually hidden entirely under the thorax. Their exoskeleton is often thickened and ha ...

, and

crayfish Crayfish are freshwater crustaceans belonging to the infraorder Astacidea, which also contains lobsters. Taxonomically, they are members of the superfamilies Astacoidea and Parastacoidea. They breathe through feather-like gills. Some spe ...

) before cooking. This avoids boiling a live shellfish which may be able to experience

in a way similar to vertebrates. The device works by applying a 120

volt The volt (symbol: V) is the unit of electric potential, Voltage#Galvani potential vs. electrochemical potential, electric potential difference (voltage), and electromotive force in the International System of Units, International System of Uni ...

2–5 amp electrical shock to the animal. It is reported the CrustaStun renders the shellfish unconscious in 0.3 seconds and kills the animal in 5 to 10 seconds, compared to 3 minutes to kill a lobster by boiling or 4.5 minutes for a crab.

Gas stunning

With gas stunning animals are exposed to a mixture of breathing gases (

argon Argon is a chemical element; it has symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abu ...

and

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

for example) that produce unconsciousness or death through hypoxia or

asphyxia Asphyxia or asphyxiation is a condition of deficient supply of oxygen to the body which arises from abnormal breathing. Asphyxia causes generalized hypoxia, which affects all the tissues and organs, some more rapidly than others. There are m ...

Carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

is the main gas used today. The process is not instantaneous, with reported signs of severe distress before respiratory failure when done with

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

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

, can be either pneumatic, or powder-actuated. Percussive stunning produces immediate unconsciousness through brain trauma. The process often requires multiple attempts. One study looking at captive bolt guns on cattle found that 12% were shot multiple times, and 12.5% were inadequately stunned.

Gallery

File:Schlachtschussapparat (modified).jpg, Captive bolt pistol File:TED Stunner Captive Bolt Technology.jpg, Modern captive bolt device File:Stunning with captive bolt gun.jpeg, Stunning a cow with a captive bolt File:Betäubung.jpeg, Directions for positioning bolt gun to ensure swift stunning

European regulations

The European Convention for the Protection of Animals for Slaughter, or Slaughter Convention (

Council of Europe The Council of Europe (CoE; , CdE) is an international organisation with the goal of upholding human rights, democracy and the Law in Europe, rule of law in Europe. Founded in 1949, it is Europe's oldest intergovernmental organisation, represe ...

, 1979), requires all solipeds,

ruminant Ruminants are herbivorous grazing or browsing artiodactyls belonging to the suborder Ruminantia that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microb ...

s and

s to be stunned before slaughter through one of the three modern methods (concussion, electronarcosis, or gas), and prohibits the use of pole-axes, hammers and puntillas. Parties may permit exemptions for religious slaughter, emergency slaughter, slaughter of poultry, rabbits and other small animals. On the other hand, the

European Court of Justice The European Court of Justice (ECJ), officially the Court of Justice (), is the supreme court of the European Union in matters of European Union law. As a part of the Court of Justice of the European Union, it is tasked with interpreting ...

(an EU institution) ruled on 17 December 2020 that member states of the European Union may also require a reversible pre-cut stunning procedure in ritual slaughter in order to promote animal welfare.

United States regulations

Stunning is regulated by the provisions of the Humane Methods of Slaughter Act (7 U.S.C. 1901), which the

Food Safety and Inspection Service The Food Safety and Inspection Service (FSIS), an agency of the United States Department of Agriculture (USDA), is the public health regulatory agency responsible for ensuring that United States' commercial supply of meat, poultry, and egg prod ...

(FSIS) is mandated to uphold under the

Federal Meat Inspection Act The Federal Meat Inspection Act of 1906 (FMIA) is an American law that makes it illegal to adulterate or misbrand meat and meat products being sold as food, and ensures that meat and meat products are slaughtered and processed under strictly ...

(21 U.S.C. 603 (b)). No similar provision exists in the Poultry Products Inspection Act of 1957 (21 U.S.C. 451 et seq.). After confirmation of the first U.S. BSE case, FSIS issued regulations (69 FR 1887, 12 January 2004) prohibiting the use of the most widely used stunning device (air-injection captive bolt stun gun) because the compressed air device (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 transmit BSE if it contained specified risk materials (SRMs include brain and CNS tissue).CRS Report for Congress: Agriculture: A Glossary of Terms, Programs, and Laws, 2005 Edition - Order Code 97-905

References

External links

{{Wiktionary
The Food and Agricultural Organisation (FAO)
outlines practical suggestions for humane handling and slaughter of livestock. Slaughter methods Animal killing