#work_animal  an animal trained for and used for heavy labor
  supertype:  animal__animate_being__animatebeing__beast__brute__creature__fauna  a living organism characterized by voluntary movement
  subtype:  beast_of_burden__jument  an animal such as a donkey or ox or elephant used for transporting loads or doing other heavy work
     subtype:  pack_animal__sumpter  an animal such as a mule or burro or horse used to carry loads
        subtype:  packhorse  a workhorse used as a pack animal
  subtype:  draft_animal__draftanimal  an animal used for pulling heavy loads

No statement uses or specializes work_animal; click here to add one.