Three things belong in any Australian Shepherd purchase conversation.
MDR1 drug sensitivity is the first, and it will matter in an emergency. Many herding-breed dogs carry a mutation affecting a protein that keeps certain drugs out of the brain, and affected dogs can react severely to normal doses of some common medications, including particular wormers and sedatives. The test is cheap and done once — put the result on your vet's file and volunteer it at every new practice.
Eye testing is the second. Collie eye anomaly, progressive retinal atrophy and cataracts all appear in the breed. Puppies can be examined by an ophthalmologist and DNA tests exist for several of these.
Merle breeding is the third and it is the one to be firm about. Breeding two merle dogs together produces a proportion of double merle puppies, which are frequently deaf, blind, or both. A responsible breeder never does it. If a litter is advertised as merle to merle, walk away.
Hip and elbow dysplasia, epilepsy, hypothyroidism, allergies and cancer complete the list.
The Malamute's own list runs to hip and elbow dysplasia, hypothyroidism, hereditary cataracts, progressive retinal atrophy, epilepsy, heart disease, bloat, polyneuropathy and zinc-responsive skin disease.