The Australian Cattle Dog (ACD) is a breed of herding dog originally developed in Australia for droving cattle over long distances across rough terrain. Today it is a versatile breed: a courageous and tireless worker an intelligent and athletic companion and a loving and playful family pet. They can bite if harshly treated they tend to nip heels to herd people and they can be aggressive with other dogs. However they are loyal and biddable and respond well to training.