Dog urine glows in the dark?

Our 5-6 year female German Shepard/Lab mix went walking with us last night and after a side trip hunting ran up to us in the dark and I saw green dots appearing on the pavement. I asked my son who was standing behind her and he saw drops falling out on to the pavement as well. The drops would glow green for about 20-30 seconds.

Has anyone ever heard of such a thing? We had her fixed after the first liter of puppies years ago. The moon was not up yet and it was quite dark but we could see a bit.