Animal euthanasia (euthanasia from Greek: εὐθανασία; "good death") is the act of killing an animal or allowing it to die by withholding extreme medical measures. ... In domesticated animals, this process is commonly referred to by euphemisms such as "put down" or "put to sleep".

Do animals suffer when euthanized?

Sometimes a mild sedative or tranquilizer is first given if the animal appears anxious or painful. ... As the solution is injected, the animal loses consciousness and within minutes the heart and lungs stop functioning. Since the pet is not conscious, they do not feel anything.

Do vets put down healthy animals?

No veterinary surgeon is obliged to kill a healthy animal unless required to do so under statutory powers as part of their conditions of employment. Veterinary surgeons do, however, have the privilege of being able to relieve an animal's suffering in this way in appropriate cases.