There have been limited studies. I'd found this info on Google Scholar a while back when I first started hearing about CBD oil being used for almost everything and I'd wondered if any kind of studies had been done on canines and found these when I searched "CBD oil pain relief study in canines":
https://scholar.google.com/scholar?h...dy+in+dogs&oq= https://www.frontiersin.org/articles...018.00165/full
Still not enough long-term, wide-ranging, large studies for me to go with it yet.