The old saying goes: You can lead a horse to water, but you can’t make him drink.
Especially if it’s a vampire horse. Those only drink blood.
However, when you do the math, they’re a lot cheaper to take care of that normal horses.
They don’t need all that veterinary work, shoes, or other crap. Maybe the occasional fancy Victorian-style leather saddle.
None of that glitter or black eyeliner crap. Fuck Twilight, dude.
Oh, and fresh victims every now and then, which if you don’t mind going through a new stable boy every few days, isn’t much of an imposition.