none, as in we dont have a limit never have, our dogs are athletes only shadow is a pet , of coarse the others are treated as pets, but they are athletes kept on exersize planes, and diet plans, and kept on a racing weight(if they were pets they would not be fat just a more normal weight) however the athletes are thin, light, agile, and bought, received, or adopted for sports not pets, so we really dont have a limit.