Australian Shepherd

17–18The Australian Shepherd, often known simply as the 'Aussie', is a medium-sized breed of dog that was, despite its name, developed on ranches in the United States during the 19th century. There is disagreement regarding the exact history of the breed prior to its arrival in the United States, and thus no official consensus on the origin of its name or association with Australia. The Australian Shepherd, often known simply as the 'Aussie', is a medium-sized breed of dog that was, despite its name, developed on ranches in the United States during the 19th century. There is disagreement regarding the exact history of the breed prior to its arrival in the United States, and thus no official consensus on the origin of its name or association with Australia. They are similar in appearance to the popular English Shepherd and Border Collie breeds, and research has found that Australian Shepherds and Border Collies are closely related to each other; both the Border Collie and Australian Shepherd are slightly more distantly related to other kinds of Collies and to Shetland Sheepdogs. Australian Shepherds rose in popularity with a boom in Western riding after World War II. They became known to the general public through rodeos, horse shows, and Disney movies made for television. For many years, Aussies have been valued by stockmen for their versatility and trainability. While they continue to work as stock dogs and compete in herding trials, they have earned recognition in other roles due to their trainability and eagerness to please and are highly regarded for their skills in obedience. Like all working breeds, Aussies have considerable energy and drive and usually need a job to keep them occupied. They often excel at dog sports such as dog agility and frisbee and are also highly successful as search and rescue dogs, disaster dogs, detection dogs, guide dogs, service dogs, and therapy dogs. They are considered the 17th-most popular dog breed in the United States. The Australian Shepherd is traditionally a medium-sized breed of solid build. They can weigh from 35 to 70 pounds (16 to 32 kg) and stand from 18 to 23 inches (46 to 58 cm) in height. The Australian Shepherd Club of America (ASCA) standard calls for the Australian shepherd to stand between 18 and 23 inches (46 and 58 cm) at the withers, females being 18 to 22 inches (46 to 56 cm) and males measuring 19 to 23 inches (48 to 58 cm); however, quality is not to be sacrificed in favor of size. Recognized Aussie colors are solid black, solid red (liver), blue merle, and red/liver merle; each of these colors may also have copper (tan) points or white markings in various combinations on the face, chest, and legs. A black or red dog with copper and white trim is called 'tricolor' or 'tri', while a black or red dog with white trim but no copper is called 'bicolor' or 'bi'. White, rather than pigment, on or around the ears is an indicator of increased risk for white-related deafness. Excessive white on the face and ears can place an individual dog at greater risk for sunburn and subsequent skin cancer. The wide variety of color combinations comes from the interaction between the color allele, which is either black (B) dominant or red (b) recessive, and the dominant merle allele (M). Together, these provide four coat-color aspects that can appear in any combination: The merle allele, which produces a mingled or patchwork combination of dark and light areas, is the coat pattern most commonly associated with the breed. This merle (M) is dominant, so heterozygous dogs (Mm) show the pigmentation pattern; however, when two merles are bred, the statistical risk is 25% of the offspring will end up with the two copies of the merle gene (homozygous). These dogs usually have a mostly white coat and blue irises, and are often deaf, blind, or both. In this case, the deafness and blindness are linked to having two copies of the merle gene, which disrupts pigmentation and produces these health defects.