This makes me sad.....

Dogs at War: Left Behind in Vietnam

Reichenbach never had another dog. After the war ended, he didn't try to track down Major the way that some handlers did, sending inquiries after their dogs, hoping to adopt them (all unsuccessfully). Someone sent him an email once, saying they'd found a record noting that Major died of a jungle disease that had been killing off their dogs. But even if Major was still alive by the time the United States forces pulled out of Vietnam, he, like all but a few of the dogs still in country, would have been left behind.

And many of these military dogs met with an unhappy end—likely euthanized by the South Vietnamese Army, with whom they were left, or worse. Many of the handlers didn't find out for years that their canine partners never made it out of Vietnam alive.

This is one of the darkest parts of war dog history, especially considering how valuable they were to U.S. troops. Roughly 4,000 dogs served in the war, leading patrols with their handlers through dense jungle terrain. Overall, they are credited with saving upward of 10,000 lives.