Probably one of the large, heavier breeds such as an Alsatian, Doberman or Rottweiler.
I would say a German Shepherd
That is a sign that your dog is in heat or pregnant
as shepherd and guarding dog
as a guarding dog and for chasing rats
The Dalmatian is traditionally a cart guarding dog. This lead to them being kept in firehouses.
Dogs are used for police , racing , guarding houses
for hunting on large animals and as guarding dog
Bull Mastiffs are very good guard dogs and are excellent with families.
As loyal as a dog waiting for its owner at the door. As friendly as a dog wagging its tail. As protective as a dog guarding its home. As energetic as a dog chasing after a ball.
All sorts of things; from guarding to companionship.
A Beauceron is a large variety of dog bred in Northern France for herding and guarding
A German Shepherd is a breed of dog, used for guarding, herding and police work.