Doesn't matter, such things threaten the horse investor lock in economics.
Many years past, an early bit of software from my student days was a side project making an easy to use database system for a horse stud farm, high status stallions being put to mares with the feed, vet visits, results, etc. all logged.
Horse racing is pretty much all about pedigree - without the lineage horses are considered valueless by the industry - super fast back country waler crosses might be acceptable for a four mile charge across open ground onto machine gun nests .. but w/out that pedigree <shrug> no Lord or up and coming billionaire is going to syndicate that horse for racing.
I imagine Polo to be much the same, in the rich set. Probably more open and accepting out on the steppes knocking about the heads of the vanquished.