Most military working dogs and many dogs that work for federal and state law enforcement are trained at Lackland Air Force Base near San Antonio in the Defense Military Working Dog School, known in the military and government as Dog School. The Army, Air Force, and Navy all have manuals that describe training standards and objectives of the dogs they obtain from Dog School. Training at Dog School emphasizes reward training, with the dog receive a reward for a correct or near-correct response, but none for an incorrect response. Verbal praise is also emphasized. Handlers are not to hit, kick, or strike a military working dog (MWD) with intent to harm. Use of a shock collar, relaxation collar, or 'Schutzhund' pinch collar, is forbidden. The training is not easy for the dogs, however. Specific requirements include the ability of the dog to work despite gunfire. MWDs must not become uncontrollable in the presence of gunfire and must initiate or continue an attack on command despite gunfire. Personnel involved in gunfire training must never back a dog down with gunfire and only blanks are used in training. When gunfire does frighten a dog or make it uncontrollable, the training manuals recommend moving the shooter far enough away until the sound of the shot does not evoke the negative behavior. Then the distance is decreased, say five yards per day. The dog will be expected to work under gunfire after about ten days of this conditioning. Training begins with small caliber weapons but may work up to mortar, artillery, and grenade simulators. Dogs are taught the command COVER, which means that the dog is to DOWN wherever he or she is. When my dog took the test to qualify as a therapy dog, the tester dropped a stack of pans behind her. If she had spooked, she would have failed. I didn't know how easy I had it.
Additional Note. Aldrovandus, writing at the end of the 16th century, says that war dogs were taught to attack men with drawn swords.