Actually, your best bet is doing local stuff. My dog was in a commercial for our local SPCA, and her dog group also did a commercial for a Chevrolet dealer in town. The company I work for also hired a local lab to do a promo. Opportunities are out there, but you need to find them. Try joining local dog clubs in your area. You'd be surprised at the contacts you'll make. If your dog can do obedience, it can most likely hit the spot for a commercial.

Hmm, maybe we all ought to become pet agents

Best of luck to you!