"We'd spend hours not sleeping, and rushing to eat meals, and staying on guard," said Caba, 26.
When a litter of puppies was born on the base where Caba served, the animals provided just the relief he needed.
"You walk in, and the dogs are wagging their tails, jumping on your legs and so excited to see you," Caba said. "You forget that you're halfway across the world, in a desert, with hostile things going on."
The soldiers began feeding, bathing and caring for the puppies, and Caba bonded with one in particular.
"She was sleeping on her back, with her mouth wide open, her tongue out a little bit and it was such a dopey thing to do -- and it's just like me," said Caba, who named the dog Cadence. "So I kind of knew that was it for me."
But a few months later, the soldiers' tour was coming to an end. Determined not to leave the dogs behind, they searched for a way to get them to America.
That's when Caba was connected with Nowzad Dogs
. Since 2007, the organization has reunited hundreds of soldiers with the stray dogs and cats they rescued while serving on the front lines.
"On every single street corner in Kabul you will find stray dogs," said Pen Farthing, a former Royal Marine sergeant who founded the nonprofit. "To be able to get that animal home to them, it closes the loop. ... They don't want to just abandon that animal."
Soldier's best friend
Farthing knows firsthand the bond that can form between a soldier and a dog. In 2006, while on patrol in Afghanistan, he and his troops encountered a dog fight.
"We broke up that dog fight not realizing that one of those dogs was actually going to adopt me," said Farthing, 45.
The dog followed Farthing back to base. They became friends, and Farthing named him Nowzad, after the town where he saved him.
"He was just war-torn and battered, just like the town we were actually fighting over," he said.
For several months, Farthing and Nowzad filled an important void in each other's lives.
"As the troop sergeant, I was there to motivate the guys and get them fired up again to go out and do the job. ... But no one was doing that for me," Farthing said. "My time with this dog was a way of de-stressing, collecting my thoughts and popping my head back in the game."
After his tour ended, Farthing went through a difficult process to get Nowzad home to Britain. He realized he not only wanted to help other soldiers do the same, he wanted to do more to help Afghanistan.
"One day you are fighting the Taliban, and the next day you are home and grocery shopping," Farthing said. "When I got home, I thought, 'What am I doing here?' I didn't want to leave Afghanistan forever."
Today, Nowzad Dogs also works to promote animal welfare in the country.
The group's shelter and clinic in Kabul are staffed by 14 Afghan nationals, four of whom are trained veterinarians. The group spays/neuters street dogs and cats and vaccinates them against rabies to reduce the stray animal population. In turn, those efforts help protect residents by having fewer rabid animals roaming the streets.
Farthing said his organization has the only official animal shelter in Afghanistan. The group also places rescued animals in caring homes there.
Journey to a new home
Farthing's group has reunited animals with nearly 700 service members from eight countries.
Soldiers' dogs and cats are first brought to the shelter in Kabul, where kennel manager and former British soldier Louise Hastie begins the quarantine process. All animals are spayed/neutered, vaccinated and micro-chipped. They spend two to three months at the shelter before being transported to the soldier's home country.
Last year, Caba and fellow soldiers were reunited in New York with the puppies for which they had cared.
"When I pulled Cadence out of the crate at (the airport), I was just so excited. I was even more excited that she remembered me," Caba said. "It kind of brought me back to coming back after a mission and having her there. It brought me right back to that feeling."
Nowzad lived with Farthing in Britain for the last six years until the dog's recent death. For Farthing, he was a constant reminder of their journey.
"My connection with Afghanistan stayed alive because of Nowzad," Farthing said. "So for me, every time I look at him, it just makes me smile. I could never have dreamed that we'd be doing something like this in Afghanistan."
Want to get involved? Check out the Nowzad Dogs' website at www.nowzad.org
and see how to help.