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Pigs panicing in a co2 stunninc chamber

CO2 stunning of pigs

Still cruel

It has been scientifically proven for many years that stunning pigs with CO2 gas leads to severe suffering. Nevertheless, about half of the more than 5 million pigs in Austria are still stunned in this way before they are killed.

With driving paddles and electric shockers the pigs are driven through metal corridors. They should keep moving forward – in the direction of the stunning system. Individually or in small groups, they are forced into gondolas. Then they go down into the gas pit. The pigs begin to gasp for air and scream. They hit their heads against the bars of the gondolas until they lie motionless on top of each other after about half a minute. These pictures first came to light in Austria in 2015 as part of the slaughterhouse scandal expose.

Hidden suffering

In contrast to electric stunning or the use of captive-bolt devices, gas stunning puts a distance between the person and animal. Deep in the gas vault, separated from the next workers by metal walls and door devices, it was apparently easier for a long time to disregard the suffering of the animals. Above all the public were unaware, thinking instead that pigs drift peacefuly to sleep. But CO2 stunning is anything but peaceful.

At least 30 seconds of agony

The pictures from the slaughterhouse scandal from several large and small Austrian slaughterhouses show immense suffering. Observations show that with CO2 stunning, between 33 and 103 seconds pass, until the pigs lose consciousness (1). If the pig is bled out without any pre-stunning, they lose consciousness approximately after 25 seconds (2). In both cases animals suffer enormously. Meanwhile, a large number of animal protection organisations have taken up this issue.

An end to CO2 stunning

There are several other possibilities that use gas mixtures of argon or helium or even just one of these noble gases as alternatives to gas stunning. These alternatives would reduce suffering. They are however more expensive and require partial changes to stunning facilities. Other stunning methods, such as electric stunning, have the potential to work faster, but are often more prone to false stunning. Lena Remich from VGT comments CO2 stunning cannot override the law against cruelty to animals on the basis of less cruel methods being more expensive. Profit should not take priority over animal suffering. Cruel practices, no matter how widespread they are, must be questioned and if necessary forbidden. Since footage of CO2 stunning was made public, one large Austrian slaughterhouse has converted to an alternative method.

Protect animals – eat veggie

If you want to avoid animals suffering, avoid animal products. Because an individual who didn't want to die is always killed.


  1. Verhoeven, Merel et al: Time to Loss of Consciousness and Its Relation to Behavior in Slaughter Pigs during Stunning with 80 or 95 % Carbon Dioxide
  2. The ESFA Journal (2004): Welfare aspects of the main systems of stunning and killing the main commercial species of animals

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