Euthanasia in Animals

The term ‘euthanasia’ is derived from the Greek terms ‘ Eu’ means good and ‘thanatos’ means death. So euthanasia means ‘Good Death’. It is an act of inducing humane death in an animal with minimal pain and distress. Euthanasia technique should give a rapid loss of consciousness followed by cardiac or respiratory arrest (or cardio respiratory failure) and the ultimate loss of brain function.

The technique should minimize distress and anxiety in animals prior to loss of consciousness. Most methods of euthanasia require physical handling of the animal. Proper handling is vital to minimize pain and distress in animals, to ensure safety of the person performing euthanasia.

Indication

Failure of treatment, suffering from excruciating pain, suffering from incurable diseases like rabies, behaviourable problem, and the owner does not want the animal any more due to some reasons. The owner has to take decision and sole responsibility for death (by euthanasia) of the animal.

Basic Mechanism of Euthanizing Agents

The euthanizing agents cause death by 3 basic mechanisms. These are

1. Direct or indirect hypoxia to cause loss of consciousness prior to loss of motor activity.
2. Direct depression of neurons necessary for life function.
3. Physical disruption of brain activity and destruction of neurons necessary for life.

Euthanizing Agents/Methods

• Barbiturates: e.g. Pentobarbital sodium @ 27 mg/lb body weight IV and 40 mg/kg body weight IP or I/thoracic. It is suitable for small animals.
• Chloral hydrate: At the dose rate of 2 g/10 kg body weight, suitable for cattle, buffalo and horse.
• Magnesium sulphate: Saturated solution (1 : 1) at 40-50°C causes cardiac arrest and death. Inject rapidly by IV or intracardiac route. Dose: Large animal – 1 g/kg body weight; Dog – 10-30 ml.
• Inhalant anaesthetics: e.g. halothane, enflurane. isoflurane, sevoflurane, methoxyflurane, with or without nitrous oxide. Carbon di-oxide (CO2) gases can be used to induce enthanasia in gas chamber after sedation. It requires special method and chamber.
• Shooting: The shot should be done from a distance of 5-8 ft at the cross point of the imaginary lines drawn from the base of two ears to the opposite eyes. It causes profuse bleeding. Species-wise Acceptable

Method for Euthanasia

Ruminant: Barbiturates, Potassium chloride in conjugation with general anaesthesia, Penetrating captive bolt.

Pig: Barbiturates, CO2, Potassium chloride in conjugation with general anaesthesia, (Inhalantanaesthetics, Chloral hydrate after sedation) and electrocution.

Horse: Barbiturates, Potassium chloride in conjugation with general anaesthesia, Penetrating captive bolt (chloral hydrate after sedation).

Cat and Dog: Barbiturates, inhalant anaesthetics, CO2, CO, Potassium chloride in conjugation with general anaesthetics, Mag sulph (MgSO4) saturated solution (IV), N2 and Argon gases (Ar) can be used.

Zoo animals: Barbiturates, inhalant anaesthetics, CO2, CO, Potassium chloride in conjugation with general anaesthetics, N2 or Argon gas and Gun shot.

Free Ranging Wildlife: Barbiturates IV or intraperitoneal, Inhalant anaesthetics, Potassium chloride in conjugation with general anaesthesia.