Australian Shepherd

Variations of Australian Shepherd colors

A black-white-copper tricolor Australian Shepherd

The Australian Shepherd is a medium-sized, athletic breed; they typically stand between 18 and 23 inches (46 and 58 cm) and weigh between 35 and 70 pounds (16 and 32 kg).[2][4] The parent club, the Australian Shepherd Club of America’s breed standard states dogs should stand between 20 and 23 inches (51 and 58 cm) and inches between 18 and 21 inches (46 and 53 cm); the standard does allow individual animals to exceed these limits slightly.

The Australian Shepherd has a moderately long and wavy double coat that has a dense undercoat and coarse topcoat; the coat is short on the face and well feathered on the rear of the legs.[4][3] The breed is known for its unique colorations and variable coat patterns, it being said no two dogs sharing a coat.[3] The breed standard allows for blue merle, red merle, solid black or solid red, with or without white markings and with or without tan points.[6]

Examples of the breed can be born with long or naturally bobbed (short) tails;[8] traditionally long tailed dogs had their tails docked, although some countries outside of the United States do not allow docking and so some long tailed and partial bob tails are allowed to be exhibited in those countries.

The Australian Shepherd is described as intelligent, active, loyal, protective, playful, and adaptive.[2][4][3] The modern breed is predominantly bred for pets; despite this, many retain a strong herding instinct and it is not uncommon for companion dogs of the breed to try to herd children or other pets.[2][5] A very active breed, the Australian Shepherd is known to become destructive if it does not receive adequate exercise.[2][5]

The median lifespans for breeds similar in size to Australian Shepherds are mostly between 11 and 13 years.[11]

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.[11]

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).[12] Dermatological and respiratory problems also ranked high.

Collie eye anomaly (CEA) is rare in the breed, but it and cataracts are a concern[13] 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.[14] Dogs with the mutation can suffer toxicity from antiparasitics such as ivermectin in high doses, and other drugs.[15] A test is available to determine if a particular dog carries the mutated gene.[16]

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.[17]

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.[18] 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.[19] 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.[19]

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.[20] 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.[21][19] Many consider the term "lethal white" to be derogatory.[22]