Does alerting a dog cause you to lose the no alerts 3,000 points bonus?
It is possible to avoid the first dog without alerting it or even having the yellow "interest" circle appear.
You need to be on the right hand wall and as the dog travels to the far left, you can swing down and under and continue to the right along the roof without alerting the dog.
In terms of the "no alarms raised" bonus, you should see the red text with the -800 score appear if an alarm is raised at all. The yellow circle of "interest" doesn't break the no-alert bonus.
No, alerting the dogs does not cause you to lose the "no alerts" 3,000 points bonus.