I tried the search function but I didn't find much directly on this subject. What was the role of man's best friend in ancient culture? I have heard that they were very important to farmers, but not from primary sources. The extent that I know of dogs is that Hades was a dog lover(see Cerberus) in their mythology, and the Romans bred certain breeds for war, but feel free to correct/enlighten me.
They had various types of hunting dogs, hounds from Britain were particularly prized, and formed a well-known British export. Molossian hounds from Epirus were also prized. The 'cave canem' (beware of the dog) mosaic in the entrance to the 'House of the Tragic Poet' in Pompeii suggests that the role of domestic watchdog existed. Literary descriptions also suggest that small 'lap-dogs' were kept as household pets. Shepherds routinely kept dogs as guards against wolves.
It's recorded that hunting dogs from Ireland were prized too.
There are also numerous tombstones to pet dogs.
(Beware the 'war dogs' idea - it seems to be much mentioned in Rome: Total War and other games, and is commonly bandied about by Rottweiler breeders etc, but I have yet to see one single mention of such dogs in the ancient texts...)
Puppies, usually black, were sacrificed to Hecate.
I don't know much about ancient canes myself, but I know that Molossian mastiffs were enormous dogs that were popular for warfare, home defense, etc. They're extinct now, but their descendants include most large dogs today, such as St. Bernards and modern mastiffs. Hope that helps, Amice!