About the Australian Cattle Dog

A storage disease of the brain described in this breed that starts late, at around six years old, with a neurological decline that keeps getting worse; there is no treatment. It is recessive. In the original study 42 of 394 healthy Australian Cattle Dogs carried it, about one in nine; a later screen of 982 found it less often, roughly one in forty.

An inherited defect in how the kidneys take back cystine, so it builds up in the urine and forms stones that can block the urethra. In this breed it is dominant: one copy can cause it and two copies cause a more severe form, and in one family only the entire males with one copy had high urine cystine, which fell after castration. In a screen of 982 Australian Cattle Dogs, roughly one in twenty-two carried it.

An inherited muscle disorder described in one Australian Cattle Dog: the muscles relax slowly after contracting, so the dog is stiff, especially after rest, with bulky muscles, and the stiffness often eases with exercise. It is recessive and looks very rare — the variant was not found in any of 982 Australian Cattle Dogs genotyped in a later screen.

An inherited defect in a pump (ABCB1, also called MDR1) that keeps some common medicines out of the brain, so some common medicines, ivermectin among them, can cause serious poisoning. It is rare in this breed — roughly one Australian Cattle Dog in two hundred carried it in a screen of 982 — and the vet should know the result before prescribing.