Alot of the time it depends on the dog. Out of 3 black tri aussies 2 have shiny coats, they are jet black and lovely. The other is red factored meainig his undercoat has a red ting to it. When he is out of coat (like now) his coat will never look shiny unless you put something in the coat. However when his is full coat, after a bath in black shampoo he comes out all shiny...

Diet and exercise also play a small part!