What can I give a dog to knock them out?

I saw how someone was completely berated on Yahoo Answers about asking how to knock out their dog. But what if the situation was for their best? I have looked for help in this situation from a vet, animal shelters, the ASPCA, and the Humane Society. I get pretty much ignored in all instances. There are 2 stray dogs that have been around my work place for about a year now. They are scared of people and run away if you try to get too close. I have tried standing for over an hour with beef jerky and cooked hamburger. They won't even get close. We feed them but they wait until no one is around before they come eat. If you try to get close while they are eating they run away. I don't own a trap and the local animal shelter will not allow me to use them. They also will not try to pick up the animals. The vet said it was a shame but would not suggest how I could catch them. I have not received a response from anyone else that would be willing to help. It's deer season here and people are shooting all around. Also, this building is dangerously close to the interstate and I'm afraid they will be hit. I need to catch them and try to help them but I can't get close. If I could make them sleep for a few hours I can get them home to a big fenced in yard and try to get them healthy. One of the dogs is pregnant and I can't think of the babies being in this environment. Please help!