Songs from the bunk beds

As I popped into my son's room to put some clothes away the other day, he was laying in his bed out of view, casually singing his own version of Old MacDonald's Farm.
(If you can't pick up the rhythm from these lyrics, don't feel bad, because there was none.)

"Old MacDonald had a farm... and on that farm he had a cow, named Crap-pee-oooo...

This was not said with the intent you might think-- just a random set of syllables he threw out there, hence I let it pass without comment.

And then, a few random lines later:

"Old MacDonald knew how to maaake a baaaaaybeeee cowww"

I'd figure that kind of knowledge has to be pretty fundamental to run a successful farm for very long, but never having run one myself, I can't say so with certainty.

I was waiting for the follow-up question that would usually come when he accidentally says something like this, but thankfully he couldn't stop freestyling long enough to ponder it.