Old McDonald had a farm

Let's listen to this song. I learnt it when I was practically a baby and now, I'm teaching it to my youngest students.

Old MacDonald had a farm, E I E I O,
And on his farm he had a cow, E I E I O.
With a moo moo here and a moo moo there,
Here a moo, there a moo, ev'rywhere a moo moo.
Old MacDonald had a farm, E I E I O...