Your dog looks like it could be crossed with an Australian Cattle dog? I have an Austrailian Cattle dog. He is very stoutly built & a bit shorter built then your dog. He is a nervous high strung dog that does trot around a lot. The Australian Cattle dogs are crossed up with the Dalmatian, Kelpie, wild Dingo dog of Australia, & the Highland Collies. Does your dog try to herd anything like cats, other dogs, or people? My dog will try to herd people & come up from behind & nip their heels. He is very much a family dog & doesn't think to much of strangers either. I like him but this breed of dog has gotten somewhat out of hand. The temperaments have changed in these dogs over the years.