Cattle Dog is a shelter label more than a single breed. Most dogs listed this way are Australian Cattle Dogs, known as Blue or Red Heelers, or mixes with one, though Texas Heelers and crosses with Border Collies or Labs turn up too. The Australian Cattle Dog was developed in nineteenth-century Australia from collie-type herders and dingoes to move cattle by nipping at their heels.
Most are medium-sized, around 30 to 50 pounds, muscular and short-coated, with a dense double coat that sheds moderately. They're quick learners, loyal to their own people and often reserved with strangers. Mixes vary in size, coat and energy, so how a particular dog actually behaves tells you more than the label does.