Field euthanasia
Euthanasia is a Greek word meaning “good death” meaning that death occurs without pain or distress. If a captured animal has been carefully evaluated, and it has been decided that it should be destroyed humanely due to overwhelming and untreatable disease or injuries, or even persistent conflict behaviour with humans, there are a number of possible methods for euthanasia in the field.
Please note that euthanasia is not acceptable in some countries due to cultural, religious, ethical or legal issues – and these should be respected.
In the majority of circumstances such animals will already be anaesthetised – preferably deeply – then:
Barbiturate overdose:
A highly concentrated commercial barbiturate solution (eg: Pentobarbital sodium, 200 mg/ml – “Euthatal”) can be given intravenously, causing death within minutes. It is used at a dose rate of 150 mg/kg which is equivalent to 7.5 ml/10 kg. If it is not possible to access a vein for the purpose, the solution can be injected directly into the heart, the liver (using a long needle inserted just behind the xiphisternum) or into the peritoneal cavity (abdomen).
Potassium chloride:
Intravenous injections of potassium chloride (KCl) affects the electrical activity of the heart resulting in cardiac arrest. A saturated solution of KCl made up in water is injected as rapidly as possible into a vein of the anaesthetised animal. Slow injections are not effective. Administer at least 50 mg/kg KCl (equivalent to 5 grams/100 kg). Potassium chloride is cheap and therefore gross overdoses are suggested. Be sure that the animal is deeply anesthetized prior to injection, giving more anaesthetic drugs if necessary. Be aware that animals euthanased with KCl solutions may have muscle spasms for a few minutes following administration.
Gunshot:
In tiger-human conflict situations, guns are usually available and a deeply anesthetized animal may be euthanized quickly and painlessly by firing a shot into the first cervical vertebrae (i.e., into the neck where it connects to the skull) with the muzzle of the gun placed directly against the cat. Alternatively draw an imaginary X connecting the left ear with the right eye and vice versa and with the muzzle of the gun close to the skull aim a shot just to one side of where the two arms of the X cross.
Exsanguination:
Exsanguination (literally bleeding out) can be used to euthanase an anaesthetised animal, but it is often slow and extremely messy. If this method is employed it is better to sever arteries than veins – the carotid arteries in the neck are suggested. Alternatively the aorta can be cut inside the abdomen.
Restriction of breathing:
As an absolute last resort, a deeply anaesthetised animal can be destroyed by preventing it breathing. The mouth and nostrils are held firmly closed until the heart fails from hypoxia. Note that vigorous terminal attempts to breath may be seen, which may be distressing for onlookers.
NB1: Animals euthanased with barbiturates or other anaesthetic overdoses must be removed from the field, and buried or incinerated after post-mortem examination. They cannot be consumed safely by any other animal or human.
NB2: Injection of air: Despite a popularly held belief, it is very difficult to euthanase an animal by injecting air into a vein. This method is NOT recommended.