I feel ya, man. My two big dogs fart all the time. I usually go to bed after the wife and the dogs, so when I walk into the bedroom, it reeks. I swear I could light a match in there and the house would explode.
Try different foods. We buy the bigass Beneful bag. It's weird, the Healthy Weight formula makes them fart up a storm, but the normal formula helps keep the farts in I guess.