Complex sentence: Initially, she was given the name "Ralph," because of the noise she made while running; but after a sharp-eyed fan pointed out that the bison was a female, the name was changed to Ralphie.
Split into simpler sentences: Initially, she was given the name "Ralph," because of the noise she made while running. After a sharp-eyed fan pointed out that the bison was a female, however, the name was changed to Ralphie.