Those of us who love horses often prefer to see them as pets, but horses are livestock, like cattle, pigs, goats and other farm animals. Livestock, itself, is not a commodity, but is marketed, sold, bred and raised to either produce commodities (milk, hides, meat, fertilizer, etc.) or provide a service (mount, physical labor, entertainment, breeding, etc.). Buying and selling livestock is definitely an investment and there are aspects of tax law that specifically cover livestock operations.
As much as my horse-besotted heart wishes it, I know most horses will not find loving forever homes where they are treated like the family pet. I know that favorite horses I cheer for during their racing careers could wind up who knows where unless they prove to be useful producers when retired from the track. Loving racehorses is not for the faint of heart, sigh.