As you approach the stables the reins fall out of your hand as they are closed up by your new hooves. You fall forward onto all fours as your butt expands and a tail sprouts, matching your mane. Jessie lets out a horrified whinny behind you, but you din't notice as you both reach the stables.
"Well, well, I'm glad to see the reluctant mare did her job anyway," the attendant said as she stroked your mane gently, you didn't know what was going on but you enjoyed the feeling of the woman stroking you. "We have a new horse for our little herd now don't we?"
Horse, what was she talking about? You looked back at yourself and whinny in fright when you realize what's happened to your body. You try to get away from the crazy woman that took away your humanity but your body doesn't want to respond as she strokes your neck with a smile.
"Of course, if you aren't mated you'll change back in a few hours, but I doubt that'll be a problem," she said and smiled at Jessie. "Now, lets see what we have here..."
She moves behind you and adjusts your tail before speaking again.