"To the surprise of many, the vast majority of the automakers that sell their wares here in the United States welcomed the EPA's decision earlier in the year that carbon dioxide and other greenhouse gases are damaging to the environment and should therefore be regulated. That has plenty to do with the desire for a single national fuel mileage standard. But transportation certainly isn't the only way we generate greenhouse gases as a society.
The first group to publicly challenge the EPA's proposed finding is the National Cattlemen's Beef Association, which filed an official challenge to the ruling on December 24th. The group questions whether there's sufficient scientific evidence that greenhouse gases are a significant cause of climate change."
http://green.autoblog.com/2009/12/31/cattle-industry-has-a-beef-with-epa-over-greenhouse-gases/