Australian Shepherd

Health
There are many health problems that an Australian Shepherd can acquire, including back and hip problems, vision problems, and pancreatic problems. Also, an Aussie can develop bladder problems and urinary infections over time. Many can be epileptic. Thyroid problems are also appearing.

Mortality
Results of a 1998 internet survey with a sample size of 614 Australian Shepherds indicated a median longevity of about 12.5 years, but that longevity may be declining. A 2004 UK survey found a much shorter median longevity of 9 years, but their sample size was low (22 deceased dogs).

The median life spans for breeds similar in size to Australian Shepherds are mostly between 11 and 13 yrs, so, assuming the results of the UK study are not representative of the population there, Aussies appear to have a typical life span for a breed their size. Leading causes of death in the UK survey were cancer (32%), "combinations" (18%), and old age (14%).

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

Collie eye anomaly (CEA) and cataracts are considered major health concerns in Aussies. Other conditions of note include iris coloboma, canine hip dysplasia (CHD), Pelger-Huet syndrome, hypothyroidism, and nasal solar dermatitis. Prior to breeding, the Aussie should be checked for Hip and Elbow Dysplasia, 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, PRA and retinal folds. The Australian Shepherd (as well as Collies, German Shepherds and many other herding dogs) are susceptible to toxicity from common heartworm preventatives (anti-parasitics) and other drugs .This is caused by a genetic mutation of the MDR1 gene .The most common toxicity is from the heartworm medicine Ivermectin found in products such as Heartgard . (Only at very high doses. Most dogs will not have problems with Ivermectin found in products such as Heartgard Plus.) A test is available to determine if a particular dog carries the mutated gene. Read here for more information.

Double Merle
Double merling or homozygous merle, also known as "lethal white" (a misnomer because it is not lethal), occurs when the resulting offspring of two merled parents inherit two copies of the dominant merle gene. Double merles are often mostly white and can have resulting hearing and vision problems as a result of having two copies of the merle gene. Homozygous merles can be deaf, blind, express iris colobomas and microphthalmia. Not all homozygous merles are affected, but most are, making the breeding of two merles ethically questionable. Breeders will either euthanize mostly white pups or in the case of poorly qualified breeders, sell them as "rare" white Aussies without disclosing the potential for health defects. 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 and/or blind pet. However, deaf and/or blind Australian Shepherds can make wonderful pets given a home prepared for their special needs.

History
The Australian Shepherd's history is vague, as is the reason for its misleading name. It is believed by some the breed has Basque origins in Spain and was used there by shepherds.What is known is that it developed in western North America in the 19th and early 20th centuries.

Breeds as we know them today did not exist before Victorian times, but local variations of the ancestors of current breeds came into America along with their owners and livestock. Included are some that are now extinct or that have merged into other breeds. These may have included British herding dogs as well as dogs from Germany and Spain. For many centuries, shepherds had interest in dogs' working abilities rather than their appearance. As a result, over time, shepherds interbred dogs that they believed would produce better workers for the given climate and landscape. In the eastern U.S., Terrain and weather conditions were similar to that of Europe, however, so the existing imported breeds and their offspring worked well there.

In the American West, conditions were quite different. During the early introduction of sheep into America, the Spanish dogs that accompanied the flocks, proved well suited for their job in the new, wild and dangerous land. They were highly valued on the open range for their ability to herd and protect their charges from predators. In the arid and semiarid areas inhabited by early Spanish settlers, temperatures reached extremes of hot and cold, and fields varied in altitude from sea level to the higher, rougher Sierra Nevada and similar mountain ranges. The ranchers in these areas often pastured livestock on remote ranges. They preferred more aggressive herding dogs that served in the capacity of herder and guardian.

With the 1849 California Gold Rush, a massive migration occurred into to the west coast, and along with easterners came flocks of sheep and their eastern herding dogs; from the southwest came people and Spanish. But it was just as effective to bring sheep in by ship, and in they came, including flocks from Australia and other regions, along with shepherds and their own herding breeds.

Dogs from Australia had already begun to be selected and bred for climates and terrains that were often similar to California.

It is not clear where the name "Australian" came from, although it is possible that many of the dogs coming from Australia were blue merle and the adjective "Australian" became associated with any dogs of that coat color.

Recent history
Development of the breed began in Arizona, California, Colorado, Idaho, Nevada and the Pacific Northwest. The breed's foundation bloodlines are depicted in the Australian Shepherd Genealogy Chart showing the relationship between the early families of dogs.

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 1940s and the early 1970s, when the Australian Shepherd Club of America was formed and the registry was started. They became popular as performing dogs in rodeos. Their stunts and skills earned them places in several Disney films, including Run Appaloosa Run and Stub: The Greatest Cowdog in the West.