The human shepherd would in many cases come to the guard dog's aid with a weapon, not letting the dog fend for itself.
The following breeds are the best at watch dog barking: If the risk is from human intruders, a suitable dog can be simply trained to be aggressive towards unrecognized humans and then tethered or enclosed unsupervised in an area the owner wishes to protect when he is not around (such as at night); the stereotypical "junkyard dog" is a common example of this.
If you’re serious about security, having a good dog or two by your side will definitely be to your benefit.
However, you can’t just select any breed you want, because not all dog breeds are the best choices to protect you.
Both guard dogs and watchdogs bark loudly to alert their owners of an intruder's presence and to scare away the intruder.