How did they know of acupuncture meridians for horses?

Acupuncture meridians for horses

I found an interesting picture about horse treatment protocols in the book, Huh Im – Ancient Korean Doctor in Chosun Dynasty. The book was written by Sohn, Joong Yang. According to the book, there were doctors in ancient Korea who specialized in treating horses with acupuncture. At that time, horses were used as an important transportation method. Horse treatment techniques were essential, and even the book of horse treatment protocols was published. “The horses share the same meridians as humans.”

* the picture from Huh Im – Acumoxa Doctor in Chosun Dynasty