Exsanguination is theloss of blood from thecirculatory system of avertebrate, usually leading todeath. The word comes from the Latin 'sanguis', meaningblood,[1] and the prefix 'ex-', meaning 'out of'.
Exsanguination has long been used as a method ofanimal slaughter.Humane slaughter must ensure the animal is rendered insensible topain, whether through acaptive bolt or other process, prior to the bloodletting.
Depending upon the health of the individual, a person usually dies from losing half to two-thirds of their blood; a loss of roughly one-third of the blood volume isconsidered very serious. Even a single deep cut can warrantsuturing andhospitalization, especially iftrauma, avein orartery, or anothercomorbidity is involved. In the past,bloodletting was a common medical procedure or therapy, now rarely used in medicine.
Exsanguination is used as aslaughter method. Before the fatal incision is made, the animal will be rendered insensible to pain by various methods, includingcaptive bolt, electricity, or chemical. Electricity is used mostly to incapacitateswine,poultry, anddomestic sheep, whereas a chemical is used for injuredlivestock.[citation needed]
Without prior sedation, stunning, or anesthetic, this method of slaughter may cause a high degree ofanxiety, depending on the process. How animals are handled and restrained before slaughter likely impacts their welfare more than whether or not they are stunned.[2] If done badly, there can be a large element of cruelty involved,[3][4][5] whereas killing under the correct conditions minimizes the pain or suffering, if any, inflicted upon the animal.[6][7][8]
Continued pumping operation of theheart during exsanguination increases the rate of depletion and thus hastensdeath by raising the fluid pressure of the blood. Because the heart operates like apositive displacement pump, blood volume reduction will not affect cardiac output efficiency. Deprivation of blood to the heart does gradually result indiminished function, but concurrently with similar death of other parts in the body as blood volume declines.
In preparation for slaughter, an animal is hanged head-down by its hind legs. Quickly after the animal is incapacitated, a very sharp knife, in an orientation parallel to the ground, is inserted through the skin just in front of the point of thejaw and below the vertebrate. From this position, the knife is drawn forward away from the spine to sever thejugular veins,carotid arteries, andtrachea. Properly performed, blood will flow freely, anddeath will occur within seconds. Sheep and duck will reach heart and liver malfunction, leading to death, in under 10 seconds; larger animals, notably cattle, may take up to 40 seconds to reach brain death. This period may extend to a couple of minutes if complications, such as arterial occlusion, occur. However, the animal's inverted position allows blood to flow more precipitously, thus making it highly unlikely for an animal to regain consciousness before it is fully exsanguinated. In any case, animal welfare advisory councils clearly emphasize that the time from incapacitation to the start of exsanguination should be prompt, recommending a time under 15 seconds.[9]
Beyond the initial cost of purchasing a captive bolt, continued usage of the method is very inexpensive. The animal is incapacitated for the duration of the procedure, so it is one of the safest methods for the slaughterer.
Jewishkashrut (kosher) and Islamicdhabihah (halal) dietary laws mandate that slaughter is performed with a cut that immediately severs the esophagus, trachea, and the large blood vessels in the neck, causing loss of consciousness and death by exsanguination. The double-edged pointed knife is prohibited. Instead, a long knife with a squared-off end is used that, in Jewish law, must be at least twice the width of the animal's neck. The operation of sticking or exsanguination is executed faster than when using the pointed knife, as four large blood vessels in the neck are severed simultaneously.
InIslamic andJewish law, captive bolts and other methods of pre-slaughter paralysis are not permissible, as consumption of animals found dead are regarded ascarrion and stunned animals that are later killed fall into this category.[citation needed] Various halal food authorities have more recently permitted the use of a recently developedfail-safe system of head-only stunning using a mushroom-shaped hammerhead that delivers a blow that is not fatal, proved by it being possible to reverse the procedure and revive the animal after the shock.[10]
Such methods, particularly involving unstunned animals, have been criticized by veterinarians and animal welfare organizations, among others. Prohibitions against unstunned slaughter have been enacted in several countries. SeeAnimal welfare controversies in shechita for further information.
Somemethods of suicide, e.g., wrist slitting, rely on exsanguination as themechanism of death.