"Beasts of England" is the song that Old Major teaches to the other animals. He claims that his parents sang it to him when he was young, although they only remembered the first three words; the song is instrumental in firing up the other animals in their pursuit of rebellion and freedom from humans. Like other parts of Old Major's philosophy, the song contains anti-human, pro-animal sentiment, and shows the strong collectivist slant that the animals initially adopt in the Laws of Animalism. Old Major gives the song a history, saying that he believes the same song was:
"...sung by the animals of long ago and... lost to memory for generations."
For that day we all must labour,
Though we die before it break;
Cows and horses, geese and turkeys,
All must toil for freedom's sake.
(Orwell, Animal Farm, msxnet.org)
The song is uniquely effective in promoting rebellion because it is easy to remember and sing collectively. The animals adopt it as their anthem and it remains part of their philosophy for a long time; eventually, Napoleon bans the song because it promotes rebellion against exactly the sort of dictatorship that he creates for his own power.
its important bc it brings all the animals togetheir as it reminds them that their fighting for freedom as in old magors speach