"giddy-up"

The other day Alex and I were practicing counting and I decided to go through animal sounds with him as a refresher.

Here is our conversation:

Me: "Alex, what does a pig say?"
Alex: "oink, oink:
"How about a cow?"
"Mooooooo"
"Frog?"
"ribbit, ribbit"
"Dog?"
"arf, arf"
"Cat?"
"meow"
"Horse?"
(pause)....."Giddy-up"

I just love that little boy!