Originally Posted by InStyle
Landseer is a colour, its still a newfoundland. Same size/coat. Not a guard dog.
We have 3 german shepherds as our yard guards. They do a wonderful job, people are always intimidated by them, and they are fantastic with the livestock. Friendly when they are told people are ok.
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A GSD may not be the best option, since the OP doesn't live on the property where the dog will be staying. GSDs really love their people and mentally do better with lots of interaction from their human handlers. I know my 3 do!
A Great Pyrenees has my vote. When raised with any type of stock, they take their pleasure in being with their "family". If you had 2, very large GP roaming the fields with your horses, then I think they'd be pretty safe from both 2 and 4 legged predators, but dog's are just a deterant. Someone very motivated in stealing your horses will simply shoot the dogs. Other precautions should be taken to ward off people, such as posted signs that the property is monitored by a security camera, a game camera hidden in the woods, pointed toward the front gate, chains on all the gates and even electrified fences. My father was having a problem with people coming on to his hunting property and doing drugs. Being a family who lives paycheck to paycheck, we really couldn't afford the real thing, but my father built a small grey box and put a lens in it and bolted it high in a tree, but still in eyesight and it looked just like a video camera. The druggies stopped hanging around immediately!! Just something to think about.