giddy-up

https://tts.langeek.co/read?text=Z2lkZHktdXA&hash=06e00882d0ab6c475e59445a74c895f8beeeb3b1&lang=en&cache-only=0&driver=googletts&accent=US

These interjections are used when a person wants to give commands to trained animals such as horses, dogs, etc.