Carbon dioxide euthanasia of farm animals and cats

There is a story today in The Times newspaper about the inhumane slaughter of pigs in their millions using carbon dioxide. I've used the word "inhumane" because that appears to be how it is considered by the authorities and experts. In 1986, two British scientists came to the conclusion that pigs slaughtered in carbon dioxide gas chambers suffered "severe respiratory distress". 90% of the 9 million pigs slaughtered in Britain annually are killed this way. There are calls to change it.

Farm pig. Photo: Pixabay.

To the best of my knowledge, unwanted domestic and feral cats at shelters are no longer killed in carbon dioxide (or carbon monoxide) gas chambers (dependent on the country). There was a time when it happened and there may still be some gas chambers in America. They've been largely phased out. A study from 1973 concluded that carbon dioxide was a suitable alternative to chloroform for euthanasia of cats by non-veterinary personnel. That moment has passed I would suggest.

Over the intervening 40 years attitudes have dramatically changed, thankfully. It's interesting to note that the study I refer to concluded that cats did not show distress when engulfed by high concentrations of carbon dioxide i.e. at concentrations greater than 60%.

An article currently published on the PETA website states that carbon monoxide poisoning used to be routinely used at animal shelters. Carbon monoxide also causes animals to suffocate. It can take 30 minutes for some animals to lose consciousness. During this time they panic and grasp for breath. Carbon monoxide poisoning has been outlawed in many American states (Oct 2020).

The Humane Society of the United States have a statement about the use of carbon dioxide in animal shelters. The statement is undated regrettably. They say that carbon dioxide chambers are troubling and that they are against any type of gas chamber in animal shelters. Evidence suggests that carbon dioxide causes pain and distress even at low concentrations.

Photo from PoC. Link to the page.

When humans are subjected to carbon dioxide exposure it is described as "excruciating". We should take that as how animals feel under the same circumstances. They suffer for several minutes until they lose consciousness.

In 2014 the AVMA (American Veterinary Medical Association) questioned the use of carbon dioxide even at approved concentrations. Euthanasia by carbon dioxide poisoning does not meet the definition of euthanasia which means "a good death". A good death needs to be painless and rapid.

It seems that it is undeniable that carbon dioxide euthanasia or killing (the better description) is distressing and at worst excruciating. It should stop being used to kill pigs in their millions in Britain which is meant to be a country concerned about animal welfare.

The UK government has a job to do here. They sometimes hide behind the mantra that Britain leads the way on animal welfare laws. They don't always, if we are honest.

It's about an attitude change in which people respect animals even if the animals are reared to feed people, which in itself is also questionable.