Bob on the day he was euthanised. Photo Maggie Osterberg (Flickr). This page in his memory.
There are two things about feline euthanasia that are worth knowing (a) how it is done today and (b) when to do it. The latter is the most difficult subject.
It is interesting to note that in probably the best book on cat health, Cat Owner's Home Veterinary Handbook, a truly excellent book that I heartily recommend, there are only 10 lines on the subject of feline euthanasia (note: the latest edition has more!). The book has 419 pages.
This is because there is not much to say about it, if we are honest. There comes a time when your cat will either die naturally and hopefully painlessly at home, or a decision will have to be made to put him or her to sleep. At this point it is worth reminding ourselves what the word "euthanasia" means. It is said that cats are euthanised at cat shelters but this is frequently untrue. They are killed, plain and simple. See also Euthanasia of Feral Cats.
Euthanasia means, "..the practice of ending a life in a manner which relieves pain and suffering..". In other words the tough decision is made between veterinarian and cat caretaker to end a cat's life because it is the humane and kind thing to do. The classic situation will be when the cat suffers from a painful and progressive terminal illness and there is no chance of improvement and where the cat is suffering.
Clearly the veterinarian will be called upon to give best advice. He or she takes the responsibility whether to euthanise or not. It must be a difficult assessment as cats hide pain and you can't ask a cat how they feel etc.
These days, at veterinarians, euthanasia is carried out "by an intravenous injection of an anesthetic agent in sufficient amount to cause immediate loss of consciousness and cardiac arrest". I have quoted the above book for absolute accuracy.
In some shelters other forms of so called euthanasia is sometimes employed probably for financial reasons. It is not cheap to kill a cat. Carbon dioxide or carbon monoxide has been used but this causes distress. This post talks about this unsettling subject in more detail, describing the various methods old and modern: Euthanise a cat.
Feline Euthanasia -- Associated pages:
The Argument for Euthanizing Feral Cats
Humanely Euthanize A Cat
From Feline Euthanasia to Home Page