Todd Helton -- We're Keeping the Horse ... Of Course, Of Course

Todd's wife Christy tells TMZ ... they had no idea the Rockies would be gifting him a horse during his send off -- but it's not a problem ... cause they just happen to have a 4,000 acre ranch (perks of earning more than $160 million).

We're told the horse -- named A Tru Bustamove -- is worth $45,000 and the Heltons already have a nickname for him ... "Busta."

Woo ha! Woo ha!!