Shepherd dogs of the mountain region in Spain/the middle east still have to defend themselves from wolves... the Kangal dog traditionally wears a spiked collar to protect him from a fight with wolfs...
Granted, these are specifically bred, Livestock Guardian Dogs(LGD's)... adults weighing 100-150+ pounds... dogs bred for nothing but fighting wolves for a long... LONG time...
... no offense... but if your dogs ever happen to bump into a wolf, I doubt a vest(or spiky collar) is gonna make a difference.
The Kangal... bad ass dog... have a few friends in Turkey that breed these... would love to have a couple some day...
Also look up Caucasian Ovtcharca...
