A lot of modern day burglers still use a crowbar.It is known by them as the "big key" I think a good,well trained dog would be more effective in this case than an alarm.
And that's traditionally been a problem, lots of alarms have gone off over the years and just been ignored.
In theory, monitored alarms are supposed to overcome that issue, but I once had an experience with phonewatch where they didn't phone to check why the alarm was going off, for about two hours after the event. All the useless fools did was wake us up for a second time that night - then offered some sort of horse "poo" excuse for the delay.
All you've got to do is put a photo of the big lad in a few of your windows, and you can be sure any intruders will move on
Photos aside, I would be confident that your dogs would be up in an instant, if they heard in unfamiliar nose, got a scent that they didn't recognise etc.