It's nothing to do with worship. It makes sense to treat the animals with kindness and respect if you are going to be injesting them. If we dont do this, then we pay the price with disease. People die from BSE infected beef and it's one of the most horrible deaths you can imagine, first you loose your mind, then you loose control of your body (and it's a long process). And all because somebody decided to feed dead cows to the living cows...
And cows that are killed when they are terrified, are full of adrenalin which makes the meat tough. The Japanese do a special type of beef where they massage the cow before death, this produces very tender meat (also very expensive). But it prooves a point, treat the animals well and you have lovely, healthy meat to eat.