My Dog the Champion.

Champion is a "diamond in the rough" story about a dog named Scout, a cattle dog who decided she didn't like herding cattle. Scout's owner, Billy, a rancher struggling to stay in business, pegs her as a useless, broken tool and has every intention of replacing her. But when the rancher's city slicker granddaughter, Madison, spends the summer on his ranch, the two outcasts form a special bond that ushers Scout into the new arena of Dog Agility Competition.