If you're asking about how the stat lists are calculated, you are looking at the max available training a horse can receive, not it's genetics.
Say your horse has 237 in one stat (white numbers above the genetics). It can be trained another 237 points, for a total of 474.
My horse has the stats 444, 421, 300, 388, 397, 386.
You would multiply all of those stats by 2, then add it up.
Or more simply, add all of those stats together, then multiply by 2.
The number you will receive is the number that would be listed on the Stat board.