How do you know they die a painless death? Can you imagine the experience of a cow when it KNOWS it is going to be butchered ! In probability you don't because you have never visited a slaughterhouse. I saw a cow which was being taken to a slaughterhouse. She was being taken by a few men and she was bouncing on the road even though there was no force or anything to indicate that it was going to be butchered. But she knew - animals also have intuition - probably better than ours.

Just because they can not speak and their body language sometimes does not overtly suggest pain and fear, it does not mean that they are not distressed. If you like eating meat, you have a legal right to have so. But, to say that they do not experience pain is a specious argument which will just make you feel better next time you eat that delicious hamburger, it does not serve any other purpose.

Also, I assume that you based you argument that they die a painless death based on the guidelines set by Govt for the butcheries. The sad truth is that they are never followed. Do you know that a large number of chickens who escape slitting of their throat in factory farming are BOILED ALIVE !

By the way, the argument that plants are also a living being and might experience pain is ludicrous. Their nervous system is not as developed as that of animals and I suppose (I wont say I know) their pain receptors are less if there are any at all. Also, even if they do experience pain, a meat eater causes double agony to living beings - to the animal he is eating AND to the plants that the animal has eaten. The energy that you get by eating animals is less than the energy that the animal derives from the plant - a very inefficient system indeed.