The Australian Cattle Dog (ACD), or simply Cattle Dog, is a breed of herding dog originally developed in Australia for droving cattle over long distances across rough terrain. This breed is a medium-sized, short-coated dog that occurs in two main colour forms. This breed is a medium-sized, short-coated dog that occurs in two main colour forms. It has either brown or black hair distributed fairly evenly through a white coat, which gives the appearance of a 'red' or 'blue' dog. While an Australian Cattle Dog generally works silently, it will bark in alarm or to attract attention. It has a distinctive intense, high-pitched bark. Cattle Dogs are service dogs for people with a disability or are therapy dogs, some work for customs agencies in drug detection, some as police dogs, others haze pest animals, such as geese, for city or state agencies, and some work as scat-detection dogs, tracking endangered wildlife species.