If your dog farts a lot, one cause may be the way they eat. If your dog wolfs down their food very quickly, they usually end up ingesting a lot more air than they would if they ate slowly. This air has to get out of their digestive some way, and the result is usually excessive gas.

There are a couple of ways to slow down your dogs eating. You can try breaking their feedings up into smaller feeding so that they eat less at every meal. Another thing to try is using a speciality bowl (http://www.lucysdoghouse.net/LucysDogHouse/bowlpp1.htm) that makes it harder for your dog to eat, so they are forced to eat slower.