Cesar Millan describes his most challenging case on “Dog Whisperer”: Gavin, a Labrador who returned from bomb-sniffing duties in Iraq with post-traumatic stress syndrome.

“That took me 80 days to set him back to a (relaxed) state, exposing him to every single sound. He was like my key chain: Everywhere I went he went with me, because if somebody made a sound and something happened and nobody helped him, that would set him back. I could work with him a week, and if I were away one day, he could go all the way back to where he came from.

“We did a lot of swimming; we went to a firing range, bringing him around loud sounds. … Every single day (you’d see progress); you’d see a dog understanding that I knew what I was doing.

“He was a super-trained dog, but the handler didn’t know how to snap him out of it when he became nervous. … If there was no sound, he was fine, but the reality is we live in a world of sounds. He would sit down and tremble. He would totally shut down.”