A dog's ears are on the top of their head. The liquified brain material would likely run out of a dog's nose. Also, a dog's brain is surprisingly small vs the size of their head so it wouldn't take long to empty.When will you know the output power is high enough...when the Dogs brains start dribbling out of their ears??
If a Dog barks, it barks for a REASON, such as bordom, pain, loneliness......fix the problem, and the barking will stop.