training it for being a guard dog?
The simplicity of that question tells me you need to do a hell of a lot more research.
Look into any local Schutzhund clubs for starters. Also stick with German or Eastern European lines, preferably working lines, as most American GSDs have been bred for show and have more issues with their hips. A lot of people will argue that even their temperament and drive have taken a hit due to being bred for the show instead of as a working dog. And if you don't buy into that just compare the bodies of a typical American GSD with a German or Czech GSD. The European GSDs' bodies will be much more boxy and lack the slope in the lower back to hindquarters that's so prevalent in American lines...solely because that pose looks good in show rings.
Socialization is key with a GSD as well as dedicated physical and mental exercise daily
. If you want a true GSD then you're going to get a high-drive working dog that needs a job, a purpose to be happy. They're not a breed that will be content just chilling on the couch all day as you watch TV.
The best advice is really simple, do your research...as much as possible. You can't afford not to with this breed. Another good tip is to look at the titles and hip rankings of the parents, grandparents, as far back as you can go. Good breeders almost without fail will have their dogs titled in Schutzhund and the higher the better (Title 3 being the highest). You also don't want to overwork them when they're young, like letting a young pup go up and down stairs for example. That can really impact their hip development and cause problems later on.
There's a ton of stuff that I haven't even mentioned that you need to know so, again, do your research.
Look for one whose parents are hip "certified". That way you get genetics that aren't likely to produce displaysia.
And be aware that there are not only different scores, but different ranking systems for the hips. So you need to know what system they're using as well as the score.
As for being a "guard dog" look into Schutzhund, that encompasses protection work, bitework, tracking, everything. Having a good tug toy especially one attached to a pole or long stick that you can flick around is a simple way to work on their drive and bite-work when they're just pups.
This post was edited on 5/1 at 1:33 pm