Exclamation used when making physical effort, such as lifting something heavy or standing up with a grunt. Often associated with older people or comedic effect.
See also: どっこい
He lifted the heavy box with a 'heave-ho'.
la-la (meaningless song syllable)
Used as a rhythmic filler in songs, similar to 'la-la' or 'hey-ho'. Not used in everyday speech.
See also: どっこい
In that folk song, 'dokkoisho' is inserted as a rhythmic interjection.