The term Sheepdog is often used by people in the Gun Community and has been for some years.  However I am not sure its accurate.  Sheepdogs may fight off wolves and coyotes, but they also help herd them… At least the working dog types do.  Some live their lives as Sheep.  Raised with them.  Stay with them.  Generally act and even look like them.  There is no one breed of Sheepdog, as its a generic term.  But over all, the term lacks accuracy for our purposes here.
Wolfhounds on the other hand…
Few breeds can be called Wolfhounds and all have the same traits.  They were all bred specifically to act as Protectors, Guardians, and some were even bred specifically to hunt Wolves.  Such as the Irish Wolfhound.  Originally called a Warhound by the early Irish, the struck fear in the Romans who encountered them. After the Romans were sent packing, the breed was refund to the Wolf Hunter we know of today.
Wolfhounds don’t try to herd sheep.  In today’s country, such a task is useless.  Over half of this nation doesn’t want to watch out for Wolves.  They think the Wolves will be nice if they are nice to them.  They are truly Sheep.  They can’t read and comprehend History.  History shows us that when Wolves have an easy meal, they well come back.  Wolfhounds naturally understand this.  We are a breed apart.  We can’t educate the Sheep.  We can’t be responsible for them.  We can only be responsible for our own families, and ignore the rest, let them live their lives as they wish.
The Wolfhounds don’t expect anyone else to fight the Wolves for them.  We train ourselves to protect those we love.  We may train together, may fight together, but we will fight on our own if needs be.
The Wolfhound can’t help but to be this way as its his nature. Its our nature. 
We are Wolfhounds.
We were born Wolfhounds, and we will die Wolfhounds.  We can’t think like Sheep.  And we can’t tolerate Wolves.