My mom used to sing us a song we called it “The donkey song” its a lullaby can you help me?

I said the donkey shaggy and brown, I carried your mother uphill and down, I carried her saftely to bethlehem town, I said the donkey shaggy and brown. I said the horse all white and red, I gave you my manger for a bed, I gave you my hay to bury your head I said [...]

has anybody ever read a book and on the last page t has greenish brown female sheep ???? if so whats it called

i think the book had a bright green cover and was about a boy andgirl that were in lve but for some reason i think he went away i cant really reber much about the book i read it about 4 years ago but i really want to find it again