Animalia Life

The Breed History
This cattle herding breed was primarily developed in California in the 1900s, but their origins trace back to the immigration of Basque shepherds. In Australia, there are similar dogs called German Coolies, but the Australian Shepherd is considered a separate breed, and was developed in the United States not Australia as the name might imply. Collies and Australian Sheepdogs figure most prominently in the ancestry of the Australian Shepherd. The Australian Shepherd Club of America was established in 1957. First AKC registry dates to 1991.

Breeding for Function
The breed excels at watching large herds. Their "eye" for scanning the herd and reacting only when necessary gives them an edge as the herder's aide. Their sensible herding judgment allows them to manage a herd with a reasonable energy outlay, resulting in the capacity to work long days. Because of their intelligence, their trainability and personality makes them suited for guide dog work, drug detection, for search and rescue missions and as companions.

Physical Characteristics
Height at Withers: female 18-21" (45.5-53 cm), male 20-23" (51-58.5 cm).
Weight: 35-70 lb (16-32 kg).
Coat: The coat is moderate in length and density, wavy or straight and moderate feathering is present on the forelegs and britches; a mane and frill are developed. Colors include red, red merle, blue merle, and black. These may be combined with markings of specified size and distribution including white and copper.
Longevity: 12-13 years
Points of Conformation: These dogs are medium in build and slightly longer than tall. The tail is either naturally bobbed or is docked to about 4" in length. A moderate stop divides the rounded muzzle from skull. An alert expression emanates from almond shaped eyes. Iris pigment is variable and can include brown, blue and amber. Ears are triangular and moderate in size, and break in a fold hanging forward or backwards. The nose is black for all but red or red merle dogs, where a liver nose is evident. Neck is moderate in muscling. The topline is level, ending in a moderately sloping croup. The thorax is deep and the ribs well sprung, and abdomen is moderately tucked up. The limbs are straight boned, feet compact and well knuckled up. Rear dewclaws are always removed. Gait is agile, and appearing effortless.

Recognized Behavior Issues and Traits
Reported breed attributes include: Affinity for children, loyal, strong guarding and herding instincts, very high intelligence and sound temperament. They are active, tend to get along well with other pets, have high trainability, are aloof with strangers and are good alarm barkers. They are average shedders and best suited to rural living or a home with a large fenced yard. They need mental stimulation to prevent boredom vices. They like to be kept busy with games and social contact.

Normal Physiologic Variations
Merle Coat Color: Caused by a dominant mutation in the SILV gene. Breeding two merle dogs together should be avoided, as homozygous dogs can be born with multiple defects, including blindness, deafness, and heart anomalies.

Drug Sensitivities
MDR1/ABCB1 Mutation (Ivermectin/Drug Toxicity): Autosomal recessive disorder in the MDR1/ABCB1 gene allows high CNS drug levels of ivermectin, doramectin, loperamide, vincristine, moxidectin, and other drugs. Causes neurological signs, including tremors, seizures, and coma. A genetic test is available for the mutated gene, showing 10.0% of Australian Shepherds are affected, and 36.9% are carriers. In Germany, 6.9% of Australian Shepherds test homozygous affected, and 25.2% test as carriers.

Inherited Disease
Hip Dysplasia: Polygenically inherited trait causing degenerative joint disease and hip arthritis. OFA reports 5.8% affected.
Elbow Dysplasia: Polygenically inherited trait causing elbow arthritis. OFA reports 4.3% affected.
Legg-CalvР№-Perthes Disease: Polygenically inherited. Can be unilateral or bilateral, with onset of degeneration usually under 9 months of age. Treat surgically if causing lameness or discomfort. Australian Shepherds found to have a 191.4x odds ratio for developing the disease versus other breeds.
Cataracts: A mutation in the HSF4 gene is associated with co-dominant cataracts in the breed, although other inherited cataracts also occur. Australian Shepherds homozygous for the mutation tend to develop bilateral nuclear cataracts, and dogs with one copy of the defective gene have a 17.7x risk of developing posterior polar subcapsular cataracts. CERF reports anterior and posterior cataracts are equally represented in the breed, and can be intermediate or punctate. Reported in 2.43% of Australian Shepherds CERF examined by veterinary ophthalmologists between 2000-2005. CERF does not recommend breeding any Australian Shepherd with a cataract. A direct genetic test for the HSF4 mutation is available.
Patella Luxation: Polygenically inherited laxity of patellar ligaments, causing luxation, lameness, and later degenerative joint disease. Treat surgically if causing clinical signs. OFA reports 1.9% affected.
Collie Eye Anomaly/Choroidal Hypoplasia/Coloboma (CEA/CH): Autosomal recessive disorder of eye development that can lead to retinal detachment and blindness. Iris coloboma is reported in 1.45% of Australian Shepherds CERF examined by veterinary ophthalmologists between 2000-2005. A genetic test is available through Optigen, that reports 1% of Australian Shepherds test as affected, and 10% test as carriers. Reported at a frequency of 4.03% affected in an Australian study.
Hyperuricosuria (HUU)/Urate Bladder Stones: An autosomal recessive mutation in the SLC2A9 gene causes urate urolithiasis and can predispose male dogs to urinary obstruction. Estimated at a carrier frequency of 3.46% in the breed. A genetic test is available.
Multifocal Retinopathy/Retinal Dysplasia: Autosomal recessive retinal pigment epithelial dysplasia causing localized multifocal retinal detachments. Age of onset from 11 to 13 weeks of age. Reported in 0.8% of Australian Shepherds CERF examined by veterinary ophthalmologists between 2000-2005. A genetic test is available.
Progressive Retinal Atrophy (PRA): Autosomal recessive inherited retinal degeneration leading to blindness. Progressive rod cone degeneration (prcd) form occurs at a very low frequency. A genetic test is available.

Disease Predispositions
Hypothyroidism: Inherited autoimmune thyroiditis. 8.6% positive for thyroid auto-antibodies based on testing at Michigan State University. (Ave. for all breeds is 7.5%).
Persistent Pupillary Membranes: Strands of fetal remnant connecting; iris to iris, cornea, lens, or involving sheets of tissue. The later three forms can impair vision, and dogs affected with these forms should not be bred. Identified in 4.39% of Australian Shepherds CERF examined by veterinary ophthalmologists between 2000-2005.10 Distichiasis: Abnormally placed eyelashes that irritate the cornea and conjunctiva. Can cause secondary corneal ulceration. Identified in 1.44% of Australian Shepherds CERF examined by veterinary ophthalmologists between 2000-2005.
Deafness: Inherited congenital deafness associated with the merle gene. In a multi-breed study; for single merles (Mm), 2.7% were unilaterally deaf and 0.9% were bilaterally deaf. For double merles (MM), 10% were unilaterally deaf and 15% were bilaterally deaf. Diagnosed by BAER testing. Unknown mode of inheritance for deafness, though dominant merle gene must be present.
Cryptorchidism (Retained Testicles): Can be unilateral or bilateral. This is a sex-limited disorder with an unknown mode of inheritance. Reported to occur at an increased frequency in the 1999 ASCA Breed Health Survey.
Persistent Hyaloid Artery (PHA): Congenital defect resulting from abnormalities in the development and regression of the hyaloid artery. Does not cause vision problems by itself, but is often associated with other ocular defects. Reported at a frequency of 5.82% in the breed in an Australian study. Identified in 0.61% of Australian Shepherds CERF examined by veterinary ophthalmologists between 2000-2005.
Idiopathic Epilepsy (Inherited Seizures): Control with anti-seizure medication. Reported to occur at an increased frequency in the 1999 ASCA Breed Health Survey.
Chronic Superficial Keratitis (CSK)/Pannus: Corneal disease that can cause vision problems due to pigmentation. Treatment with topical ocular lubricants and anti-inflammatory medication. Australian Shepherds are a breed with increased risk of developing CSK. The disorder usually occurs between 4-7 years of age.
Cystine Urinary Calculi: Caused by a metabolic abnormality in cystine metabolism. Australian Shepherds are a breed with increased risk of developing cystine calculi.
Microphthalmia: Microphthalmia with coloboma appears to behave as an incompletely penetrant recessive trait in the merle Australian Shepherd dog. Homozygous merle dogs are usually blind, while heterozygous dogs can be less severely affected.
Anterior Crossbite, Brachygnathism, Cerebellar Vermian Hypoplasia, Cutaneous Lupus Erythematosus, Diabetes Mellitus, Factor VIII Deficiency, Osteochondrodysplasia, Panosteitis, Patent Ductus arteriosis, Pelger-Huet Anomaly, Persistent Right Aortic arch, Portosystemic Shunt, Prognathism, Pulmonic Stenosis, and von Willebrand's Disease are reported.

Isolated Case Studies
Methylmalonic Aciduria and Cobalamin Malabsorption: Documented in an Australian Shepherd kindred, due to an autosomal recessive mutation in the gene amnionless (AMN).
Neuronal Ceroid Lipofuscinosis: Three 18 month old Australian Shepherd littermates presented with a 1-month history of progressive vision loss, hypermetria, tremors, and personality changes including hyperesthesia. NCL was confirmed on necropsy.
Peripheral Neuroectodermal Tumor: A peripheral primitive neuroectodermal tumor (pPNET), most consistent with a human Ewing's sarcoma, is described in a 5-month-old male Australian Shepherd puppy.
Myofibrillar Myopathy: A 1-year-old male neutered Australian Shepherd dog was evaluated for chronic lameness, contractures, and exercise intolerance. Cardiomyopathy, and myofibrillar myopathy with accumulation of desmin was identified.
Multiple Skeletal Defects: A family of Australian Shepherds was identified with a syndrome including cleft palate, polydactyly, and often syndactyly, shortened tibia-fibula, brachygnathism and scoliosis lethal to males. The disorder may be due to an x-linked gene, or a sex-influenced autosomal gene in conjunction with instability of the merle locus.
Anemia and Osteopetrosis: Case study of a 1-year-old, male Australian Shepherd Dog with severe nonregenerative anemia associated with osteopetrosis. The anemia was attributed to failure to develop normal marrow cavities combined with failure of extramedullary erythropoiesis.

Genetic Tests
Tests of Genotype: Direct tests for CEA/CH, retinal dysplasia, and prcd-PRA are available from Optigen.
Direct test for MDR1 (ivermectin sensitivity) gene is available from Washington State Univ. vetmed.wsu.edu/depts-VCPL/ test.asp
Direct test for increased cataract susceptibility is available from the Animal Health Trust.
Direct test for HUU is available from the UC-Davis VGL and the Animal Health Trust.
Direct test for skin and nose color (black, clear red, brown (red), and dilute colors and black or brown pigmentation on the nose) is available from HealthGene and VetGen.
Tests of Phenotype: CHIC Certification: Required testing includes hip radiographs, elbow radiographs, and CERF eye examination. Optional recommended testing for thyroid profile including autoantibodies, and direct tests for CEA/CH, and MDR1. (See CHIC website; caninehealthinfo.org).
Recommend BAER testing for deafness, direct test for cataract succeptability, patella examination, and cardiac evaluation.

Miscellaneous
- Breed name synonyms: Aussie, Australian Shepherd, Pastor Dog, Bob-tail, New Mexican Shepherd, California Shepherd, Spanish Shepherd (historical).
- Registries: AKC, UKC, CKC, KCGB (Kennel Club of Great Britain), ANKC (Australian National Kennel Club), NKC (National Kennel Club)
- AKC rank (year 2008): 29 (6,471 dogs registered)
- Internet resources: Australian Shepherd Club of America Inc: asca.org
Australian Shepherd Health and Genetics Institute, Inc. (ASGI): ashgi.org
Canadian National Australian Shepherd Association: cnasa.ca
Australian Shepherd Club of the United Kingdom: ascuk.co.uk