The first step in treating your pets gas is addressing diet. Any food that is purchased at a grocery store is typically based with substandars meats and excessive fillers such as corn & wheat. Just as these foods can bring havoc on our digestive tract, they will our furry friends as well.
My cats had similar issues (gas, IBS,etc.) and I switched to California Natural. There are several brand you can try such as Wysong, Innova, & Canidae to suit your pets palate.
Premium foods do cost more, but the quality & span of your pets life can increase with good feeding. I have enclosed a link which will provide further details and suppliers.
http://www.onlynaturalpet.com/?Click=5
Good luck :-)
LiddyBea