Left in a rental property...now my best friend!

This dog was left behind in a rental property...

Years later, he's my best friend! No idea what kind of dog he is, though. Google image search brings up "New Zealand Huntaway," but there don't seem to be any breeders of that type in the United states.

Regardless, he's the best dog! Full of energy, well-behaved, and obedient. Loves to run!

Edit: His name is Nimbus 2000