Making aggressive war dogs is something humanity tried before. Mastiffs and Chow Chows are two examples. They often attacked and killed their human masters.
Really I think we should extinct the practice of training attack dogs. In US police action they're abused to escalate to violence quicker than an officer would resort to firearms.
Armored dogs in war would be responed to like mechanized armor. A dozen of my cheap flying explosive drones will make short work of your expensive dog.
But then, the US hasn't caught up to the tech of cheap drones.