Change the "Min. object size" in Trigger -> Motion Sensor | Configure to something that is larger than your micro-dog
You could also use zones to highlight things such as windows or doors and create the zone a number of inches off the floor. On a 7' tall door, you don't typically need to record the bottom 2' of that as it's unlikely a thief will wiggle in on their belly nor is it likely your dog is entering the door from 4' up. Unless, of course, your dog flies -- in that case, keep recording that sucker!