The Australian Shepherd, aka Aussie, breed began as a valuable "ranch hand" on ranches/farms/homesteads here in the United States . Over the years folks/society changed, and so too did their needs. The Australian Shepherd began to find themselves in the hands of those who had no need of a ranch hands, instead Aussie fanciers found other "work' for their dogs to do. Their Aussies became competitors in conformation, obedience, tracking, Agility, flyball, free style, dock dogs, and protection. Aussies were trained for therapy work, SAR, police dogs, and as family companions. Today the Australian Shepherd continues to evolve and change as it finds itself in new countries, living under new government laws, and with humanity as a whole changing its thoughts/views on animal ownership.
Due to the variety of "wants" breeders/fanciers desire from this breed, Aussies can be found in several colors Black (tri/bi), blue merle (with/without copper), Red merle (with or without copper), Red (tri/bi), sizes (around 18" to 23"), and temperaments. There is also what we call "show" lines vs. "working" lines and many pedigrees have a combination of. Although no matter what a dog's family has done in the past, it does not automatically imply that all their puppies will be champion/working/performance quality dogs. Within each litter there are certain pups best suited for particular jobs, while other puppies are best suited to be family companions. Like us humans, just because our parents and grandparents had particular jobs and/or succeeded in those professions does not mean we will or be able to do the same thing they did. Thus having a good knowledgeable breeder who can help you find the pup that is best suited to your needs/wants is worth its weight in gold.
Within the Aussie breed there is several health concerns all potential owners should know about. Epilepsy, Cancer (such as hemangiosarcoma), Cataracts, hip displasia, auto immune problems (such as lupus), allergies, and reactions to drugs (such as ivermectin) are just a few of the issues this breed has been battling. No lines are "clean" from health problems. No matter what anyone claims.
There are many great resources both in print and online to learn more about this truly incredible Australian Shepherd breed. Please before you make a hasty decision about getting an Aussie pup, be sure to do your research first. If possible go out and meet various breeders, rescues, and Aussie fanciers as you can. Take it slow and find the puppy/dog that is best suited for you and your family.