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 is it a versatile breed; a courageous and tireless worker, an intelligent and athletic companion, and a loving and playful family pet. The dogs have either brown or black hair distributed fairly evenly through a white coat which gives the appearance of red or blue dogs. They have been nicknamed “Red Heelers” and “Blue Heelers” on the basis of this colouring, and their practice of moving reluctant cattle by nipping at their heels.