The deer from the farm that I hunt had that gasifying effect on all who ate it until the property owner limed the soil to alter the pH. After that, no more gas, and never a problem since. The deer on his property gorge on high quality hay grass all year long, preferring that to whatever grain crops may be in the neighboring fields. My guess is that the animal's diet plays a role in the gas production. As for good gas? If you can sell it, maybe, but otherwise, no.