Lord Winston is a distinguised scientist and a Labour peer. In a debate on methods of slaughter in the House of Lords on 16 January 2014, at 2:24 pm, he said this about kosher (i.e. non-stun) methods of slaughter:
My Lords, what other religion argues that its animals should not work on the Sabbath? And we do not “seethe the kid in his mother’s milk” because that seems cruel somehow. I would argue that the notion of animal protection is stronger in Judaism than in any other world religion.
I want to speak purely as a scientist. We have heard a number of assertions here which are not scientific. With all due respect to the noble Lord, Lord Trees, death is not caused by exsanguination; it is due to interruption of the blood supply to the brain, which is immediate and has been measured. The problem with EEG measurements—electrode recording—is that they have been shown to be unsound. Indeed, the only way that you could detect pain would be by positron emission scanning of the brain, which clearly does not show any activity at all within two seconds once the blood supply has been cut. I would also argue that shechita is a much more humane method than stunning. Contrary to what some have said, it is a better method of killing animals because there is less suffering. Animals have to be calm and they are not manhandled roughly.
The noble Lord, Lord Trees, is not the only one who has been to an abattoir. They are not pleasant places. It is never pleasant to see any kind of animal killed under any circumstances, but the truth is that under the Home Office Act we would not be allowed to slaughter laboratory animals with stunning because it would not be regarded as a proper way of culling an animal in a laboratory. It would have to be done by a method which is much closer to cutting the blood supply to the brain.
I emphasise that what has been said about pain is another assumption. Of course animals may move after the brain is severed but the brain itself does not perceive pain if it is damaged and, in fact, none of the organs below the skin has pain fibres. You have some pain fibres in your trachea but they are very small. The evidence that animals suffer severe pain after one cut with an extremely sharp knife is extremely arguable. The truth is that, once you are unconscious, nobody knows what the perception of death or pain is.