The Australian Shepherd carries the MDR1 mutation at high frequency — the gene that governs how the blood-brain barrier handles certain drugs. Dogs with two copies can react severely, sometimes fatally, to ivermectin and to a list of other common medications including some anti-parasitics, sedatives and chemotherapy agents. Sensitivity to ivermectin appears explicitly on the breed's condition list here.
There is a cheap DNA test. Every Aussie should have it, the result should be on the file at your vet, and no Aussie should receive a drug on the MDR1 list without the status being known. This is the most actionable single fact on this page.
The breed also carries hip and elbow dysplasia, epilepsy, and a set of inherited eye conditions including Collie eye anomaly, progressive retinal atrophy and cataracts, all of which a breeder should have screened.
The Akita's burden is autoimmune and endocrine — immune-mediated disease, hypothyroidism, progressive retinal atrophy — plus bloat as a deep-chested breed, and a known sensitivity to anaesthesia worth flagging to any unfamiliar vet.
The Aussie lives longer: 12 to 15 years against 10 to 13.