Near Perth, mine is a dog (6)
I believe the answer is:
collie
'a dog' is the definition.
(collie is a kind of dog)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for collie that I've seen before include "Breed of sheepdog" , "Sheep-herding dog" , "shepherd's gofer" , "Breed of dog" , "Type of sheepdog" .)