Doraemon: Nobita's Animal Planet(1990)

Doraemon: Nobita to Animal Planet

Nobita went to a world of animals through the "Wherever Gas", the substance to let you travel anywhere, same as the "Wherever Door" Doraemon uses. They came across with Chippo, a boy who looks like a dog and very adventurous. A group called Numiges plans on taking over the animal planet. Doraemon and friends plan to stop them with the animal's help.

(Source: Anime News Network)