I don't like dogs much, but Aww, your story was sweet.
My reiki experience with animals was in this case with a horse. Now the horse was lame for some reason and was standing in a field. I decided to send some reiki with the intent that if the animal needed it, let it be so.
So there I was feet away from the horse, when suddenly it started to shake its head in a kinda sleepy way and just laid down in a drowse with a snort. Horse is fine by the way, lame went bye byes.
I gave reiki to kittens a bit wild, since have calmed down and always underfoot!
Happy times.