That pup of yours
The bullmastiff as a breed was developed in England in the late 19th century to help gamekeepers catch poachers. There was a need for a powerful, fast, rather silent dog that could work as a team with the gamekeeper and take care of both the poacher and the poacher’s dogs. The foundation for the breed is a cross between the mastiff and the 19th century type of bulldog.
Sounds about right for the job required.