Ginga Densetsu Riki (manga)

In a small village in Japan, an Akita named Riki is born, son of the bear hound Shiro. Riki is overlooked because of his size, and continues to live with his mother. When his mother is given back to her original owner, Riki escapes to find her. He is attacked and saved by Shiro, who doesn't realize he is his son. Riki aspires to be like Shiro and, through his own will, becomes stronger. Shiro is later killed by a giant bear named Akakabuto, and Riki is trained to be a prized bear hound who can kill Akakabuto.

ok basically you have a bear hound named Shiro, the most famous dog in the vilage...he produces a pup that everyone overlooks as being able to survive..later is to be named Riki. Riki hears tales about his father and dreams of being like him and when he is seperated from his mother he is attacked and is saved by Shiro...Riki then trains to be like him. During his training he saves a boy named Daisuke and the owner of Shiro is out hunting Akakabuto (demon bear) and Shiro is killed by it and Riki is taken by Shiro's owner and trained to fight the Akakabuto in the up coming manga.