Mary spoke with the head vet up at GDB and passed along the information to all of us so I thought I would pass it along to all of you.
Colorado has a very, very small case of elbow dysplasia in his front right leg. This, while it shouldn't really bother him later in life, rules him out as a Guide because pulling on the harness would irritate his leg and eventually cause him pain. He said that they rate dysplasia from 1 to 3 and Collie is a 1. So, that's quite a relief. He said that he should be fine and happy the rest of his life as long as he stays lean (no extra treats for Colorado) and doesn't fetch or jump for things like frisbees.
All in all, not really a bad case. This might mean that he is still eligible for the D4D programme or any other community placement. I'm glad there's a chance he might still be out there making some one's life all that much easier. But if he comes home as a pet that's wonderful too!