Do you mean you want to use a hemp rope to tie them up? Hemp ropes are normally fairly heavy, and would probably only be good on very large dogs. Plus it is very rough,, might cause skin irritation.
Some is as long as it is given in the correct dose. Here is a link to an article that may help you.
I know that sometimes cbd oil is being used to relieve pains and treat arthritis, it is the only application of hemp for pets I know. Btw I tried vaping weed with a dry herb vape pen vaporizer Yocan Evolve D Plus and it is really a great pain reliever.