Just about any of these are good for guarding the flock and being loyal and protective to its owner and their family (depending on if its immediate family). (russiandog.net)
They are big shaggy white dogs so they fit right in when guarding their flock of sheep. (pethelpful.com)
Exhibiting a unique elegance of bearing and movement, his soundness and coordination show unmistakably the purpose for which he has been bred, the strenuous work of guarding the flocks in all kinds of weather on the steep mountain slopes of the Pyrenees. (akc.org)