Beasts of England

I wondered if the song Beasts of England itself was perhaps a parody of another song. While looking this up (and I don't think it is a parody by the way) I read somewhere where it said that the Soviet Union eventually replaced its original anthem (The Internationale) with the National Anthem of the Soviet Union. In the book, I believe that the replacing of Beasts of England symbolizes the fall of the ideals that carried the animals to freedom. In short, that was when animalism died. It had been slowly ailing, but I believe it finally passed away when the pigs outlawed the song that the animals sang on the very night the revolution was conceived.