Australian Shepherd

The Australian Shepherd is traditionally a medium-sized breed. 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.[1]

Variations of Australian Shepherd colors

Recognized Aussie colors are solid black, solid red (liver), blue merle, and red/liver merle;[8] 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:[11]

• Black tri, with copper points, white markings, or both on the face, collar, legs, chest, underbelly - solid black dogs are equally desirable as ones with copper or white.
• Red (liver) with or without copper points or white markings on the face, collar, legs, chest, underbelly - either white or copper points are required. Solid red dogs are equally desirable as ones with copper or white.
• Blue merle (a mottled patchwork of gray and black) with or without copper points or white markings on the face, collar, legs, chest, underbelly - neither white nor copper points are required. Solid Merle dogs are equally desirable as ones with copper or white.
• Red merle (a mottled patchwork of cream and red/liver) with or without copper points or white markings on the face, collar, legs, chest, underbelly - neither white nor copper points are required. Solid Merle dogs are equally desirable as ones with copper or white.[12]

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.[13] The tri-colored (red, black, and white) Merles will have a 1/4 chance of being blind due to the recessive genes when breeding two Merle colored dogs for the recessive fur color.

All black and blue merle dogs have black noses, eye rims, and lips. All red and red merle dogs have liver or brown noses, eye rims, and lips.

Red merle with copper points and one brown eye and one blue eye, blue merle with copper points with blue eyes

Also, great variety is seen in the Aussie's eye color, and they are often heterochromatic. An early nickname for the breed was "ghost-eye dog". Aussie eyes may be any shade of brown or blue; they may have two different colored eyes, or even have bicolored or "split eyes" (for example, a half-brown, half-blue eye), which appear to be linked to the merle coloration. Merled eyes occur, as well, where one color is mixed in and swirled with another. Any combination of eye color is acceptable in the breed standard, so long as the eyes are healthy. In general, however, black Aussies (self, bi-color, or tri-color) tend to have brown eyes, while red (self, bi-color, or tri-color) Aussies tend to have amber eyes, though these Aussies may also carry the blue-eyed gene.

The merle phenotype in Australian Shepherds is very similar to the coat color in Mitf mouse mutants.[14]

Although some Aussies are born with naturally bobbed or partially bobbed (stubby) tails, the majority are born with full, long tails. Breeders have historically docked the tails when the puppies are born. In the United States and Canada, the standard calls for a natural bob or docked tail not to exceed four inches as a defining characteristic. Any natural tail length is permitted when showing in Europe, where docking has been banned in most countries, including the United Kingdom.

The median lifespans for breeds similar in size to Australian Shepherds are mostly between 11 and 13 years,[23] so, assuming the results of the UK study are not representative of the population there, Aussies appear to have a typical lifespan for a breed their size.

Results of a 1998 internet survey with a sample size of 614 Australian Shepherds indicated a median longevity around 12.5 years, but that longevity may be declining.[23]

Based on a sample of 48 still-living dogs, the most common health concerns noted by owners were eye problems (red eye, epiphora, conjunctivitis, and cataracts).[24] Dermatological and respiratory problems also ranked high.

Collie eye anomaly (CEA) is rare in the breed, but it and cataracts are a concern[25] in Aussies. Other conditions of note include iris coloboma, canine hip dysplasia, Pelger-Huet anomaly, hypothyroidism, and nasal solar dermatitis. Prior to breeding, the Aussie should be checked for hip and elbow dysplasia and DNA tests performed to show the dog to be free of the MDR1 mutation, cataract mutation, and CEA. Tests should also include those for thyroidism and clearances for other known eye diseases like colobomas, progressive retinal atrophy, and retinal folds.

Some Australian Shepherds (as well as Collies, German Shepherds, and many other herding dogs) are susceptible to a genetic mutation of the MDR1 gene.[26] Dogs with the mutation can suffer toxicity from antiparasitics such as ivermectin in high doses, and other drugs.[27] A test is available to determine if a particular dog carries the mutated gene.[28]

Hip dysplasia is a heritable condition where the femur does not fit securely in the pelvic socket of the hip joint. This problem can exist with or without clinical signs, meaning some dogs feel pain in one or both rear legs.[29]

An example of an abnormal eye of a double merle, "lethal white", Australian Shepherd: The abnormally small left eye is known as microphthalmia, and the pupil shows signs of subluxation which is dropped, not centered.

Double merle or homozygous merle occurs when the offspring of two merled parents inherit two copies of the dominant merle gene. The odds of this are 25% for each pup born from such a litter.[13] Double merles often have excessive light or white areas and can have hearing and vision problems as a result of having two copies of the merle gene.[15] Homozygous merles can be deaf or blind, or express iris colobomas, retinal detachment, cataracts, persistent pupillary membrane, a displacement of the lens, equatorial staphyloma, night blindness and microphthalmia. Audio impairment or deafness usually develops after the birth of a puppy with their ear canal still closed. The white color of double merles is produced due to the lack of melanocytes which provide high potassium levels in the endolymph surrounding the cochlea's hair cells. There is no surgery or treatment that can reduce the damage. Loss of hearing is directly linked to the amount of pigmentation cells a dog has. The same pigment that is lacking in the ear can also be lacking in the eyes, affecting its development. Although many believe that only dogs with blue eyes have eye problems, it is not correct. Due to the contrast between eye problems and blue eyes, eye conditions in blue-eyed dogs are much easier to spot.[15]

Not all homozygous merles are affected, but most are, making the breeding of two merles a very touchy subject. Some breeders euthanize mostly white pups, while others may attempt to sell them as "rare" white Aussies without disclosing the potential for health defects.[30] A large percentage of homozygous merles sold eventually end up in rescue and shelters, as the average family is ill-prepared to take on a deaf or blind pet. However, deaf or blind Australian shepherds can make wonderful pets given a home prepared for their special needs. They are an intelligent breed, which generally learn hand signals with ease.

The term "lethal white" originated from horses born with lethal white syndrome, and has since evolved to often describe dogs born with the double merle trait. This trait is found in many breeds, but most commonly found in Australian Shepherds. The name "lethal white" is a misnomer, as this genetic condition is not lethal to the dogs; it is often the breeder who is lethal to the pups by culling them immediately after birth.[31][15] Many consider the term "lethal white" to be derogatory.[32]

Development of the breed began in the American West. The breed's foundation bloodlines are depicted in the Australian Shepherd Genealogy Chart showing the relationship between the early families of dogs.[35] The American Kennel Club (AKC) ranked the Australian Shepherd as the 17th-most popular breed in the United States in 2016.[36]

Selective breeding for many generations focused on aspects of the dog that enabled it to function as an effective stockdog in the American West. It had to handle severe weather; have plenty of speed, athleticism, energy, and endurance; and be intelligent, flexible, and independent; while remaining obedient. The actual foundation for the Australian Shepherd was established between the 1940s and the early 1970s, when the Australian Shepherd Club of America was formed and the registry was started.[37]

Their stunts and skills earned them places in several Disney films, including Run Appaloosa Run and Stub: The Greatest Cowdog in the West.[11][38] An Australian shepherd was featured in the film Flight of the Navigator (1986) and the TV series Flash Forward (1996). More recently, an Australian Shepherd starred in the film Famous Five (2012) and its sequels.

In June 2017, U.S. Vice President Mike Pence and his family adopted a Blue Merle Australian Shepherd named Harley.[39]

The Australian Shepherd Club of America (ASCA) was founded in 1957 to promote the breed. The National Stock Dog Registry became its official breed registry, which continued until ASCA took over in 1972.[40]

In 1975, ASCA created a breed standard, describing exactly how an Australian shepherd should look and be constructed (its conformation to the Standard). It developed more uniformity in the breed and standardized the type.

In the United States, the American Kennel Club (AKC) is the primary registry for purebred dogs, and first recognized the Australian Shepherd in 1993 as a member of the Herding group.[8] However, many Aussie breeders felt the AKC put too much emphasis on breed conformity and not enough on performance, so the ASCA declined to join the AKC. Those breeders who felt that AKC membership had its advantages split off from ASCA to form their own Australian Shepherd club, the United States Australian Shepherd Association, created their own breed standard, and joined the AKC in 1993. The decision about affiliation with the AKC remains controversial, as it does with many performance breeds.

The Fédération Cynologique Internationale (FCI-World Canine Organization) recognized the Australian Shepherd for international competition in 2007, in Group 1 Sheepdogs and Cattle Dogs as breed number 342.

The Miniature Australian Shepherd was developed by breeders looking for smaller dogs ranging in size from 14 inches to the Aussie standard. In 2010, NAMASCUSA renamed the breed Miniature American Shepherds and subsequently changed their name to MASCUSA, The Miniature American Shepherd Club of the USA. This new breed gained acceptance into the AKC Miscellaneous class in June 2012 with the sizes written in the standard as females from 13 to 17 inches and males from 14 to 18 inches.

In addition, an emergence of an even smaller version occurred, referred to as the Toy Australian Shepherd, with adult males weighing 12–15 pounds (5.5–7 kg) and all dogs falling under a 14-inch height at the withers. Many breeders and owners of Australian Shepherds consider the Mini and Toy to be separate breeds; others consider them to be downsized versions of the same breed. While the Mini size can be attained through selective breeding of small Australian Shepherds, the Toy size is typically a result of cross breeding with other toy breeds. ASCA and AKC consider both variants to be separate breeds.[1]