A Belgian sheepdog is one of four variants of sheep-herding dog bred in Belgium, especially the Groenendael variant.

The Mallie and Lanni make great guards out of the four Belgian Sheepdogs but I would suggest a German Shepherd as they are so lovable as well but do their duty with flying colours.

I'm going to presume you mean Belgian Shepherd Dog?

Yes, the German Shepherd di have a part in creating all four variaties of The Belgian Sheep dog although the Teruven had German Shepherd used most in its development.

A Belgian Mastiff is a large breed of dog.

A sheep dog.