Mixed Up on Methane?

I haven't been following the Copenhagen Climate Talks very closely. I'm not entirely sure that we can change the climate to such an extent as some are suggesting. But today when I was driving, I heard a suggestion on the news. Seemingly, climate protesters and Eco-warriors want us to eat less meat, to cut down on our cow consumption. The methane produced by a cow or sheep is much worse than the CO2 produced by cars.

That strikes me as a slightly odd suggestion. Surely if we reduce eating as much meat, then more animals will survive, thus producing even more methane than if they were being eaten?

So do your bit to stop global warming and have a burger and steak - from a local farm, obviously to reduce transport costs and gasses!