From the explosives dog sniffing around Barack Obama's car, to the drugs dog discovering a cocaine shipment on the Mexican border, wherever dogs are at work around the world, there is a good chance they came from the Netherlands. The Netherlands is the world's largest supplier of tracking dogs. Here they are bred and raised, and then sold for up to 6,000 euros to police forces, customs services and even armies from around the world.

Piet van den Broek (54) is the former head of Nato's tracking dogs division. After the Cold War ended, Van den Broek's job was on the line, and he started his own company, K9 Dogcenter. (Many dog companies have K9, short for canine, in their name.) Soon he was exporting dogs to Greece, Mexico, Egypt, the US. "They didn't know anything about dogs," says Van den Broek, "if it had a head and a tail they would buy it."

US army in Iraq, Afghanistan

This naiveté has since disappeared, but the demand for tracking dogs from the Netherlands has only gone up. "We have waiting lists," says Gerard Dashorst, director of K9 Midden-Nederland, one of the four biggest tracking dogs companies in the Netherlands. "A lot of them are going to the US army in Iraq and Afghanistan these days. But we also ship dogs to France, China, Germany, Dubai, Egypt, Colombia – some 400 dogs go to 33 different countries every year."

In fact, demand is so high that the Netherlands is running out of dogs. In order to meet demand Dutch companies now buy puppies from traders who get them from Eastern Europe. After they are 'socialised' in the Netherlands, they go abroad for specialised training as tracking dogs.

Why are dogs from the Netherlands so popular? Van den Broek: "The Netherlands domesticated dogs centuries ago. We are a nation of dog lovers, unlike many other countries where dogs were kept out of sight." Because of this, he suspects Dutch people have developed a special sense for dogs. "I think it's in the tone of voice. In the US policemen will just tell a dog 'good boy' and that's it. We put more emotion in our voices when we talk to the dogs."

Another aspect is choosing which dogs to crossbreed, says Sandra Blonk, a dog trainer for S&R Policedogs. "Just like with horses and cows we started crossbreeding dogs much sooner than anyone else. Dogs were used here very early on for guarding cattle."

Competition from China

There is competition from abroad: China has recently opened its own breeding stations. Van den Broek: "But they are too large-scale; the dogs don't get enough attention. Dogs, like people, needs to experience things to become socialised. They need to go to sidewalk terraces , the shopping mall. The best tracking dogs are from private owners who have taken the time and the trouble to educate them."

A good tracking dog has to be in touch with his primal instincts, says Van den Broek. "They have to be strong-willed. A dog breathes in and out four times per second. In places where the air is dry and warm, they tire easily. If a dog still wants to track in those conditions he has what it takes."

But they also need to be social. Van den Broek challenges them with the craziest behaviour to see how far he can go without the dog biting him. "That's part character, part education," he says. They also need to comfortable with smooth surfaces. "Many dogs who grew up outdoors are afraid of airport floors."

In his training Van den Broek uses tennis balls impregnated with the smell of hashish, gunpowder or other explosives. "The dog will look for the ball, not the drugs. He's thinking: that's my toy. As soon as he finds the ball he sits down. A good dog will take four months to train. Explosives dogs take a bit longer; they have to be more careful."

Van den Broek's own biggest catch was in Düsseldorf, during the search of a house belonging to a RAF terrorist suspect. "Behind one of the cellar walls was an entire arsenal of grenades and kalashnikovs."

Demand is only on the rise in the Netherlands. "We are getting more requests from private companies. They'll ask us to check temp workers for soft drugs, or cruise ships or dock workers."

A new phenomenon is asylum seekers trying to hide aboard container ships. Van den Broek: "If they are caught the shipping companies risk big fines." So his company is hired on a regular basis by shipping companies in Dutch and Belgian ports. "With daily success," says Van den Broek.