At least at first, then a new urge hit you, a thirst that made it hard to resist taking a drink from the only source nearby. the mare looked back at you as she adjusted herself and you fell forward onto all fours and moved forward until you were right up against her belly, and more importantly her teats.
The mare let out a slight whinny as you took her teat into your mouth and began to suckle at it. For a moment nothing seemed to come from it before milk started to flow out of her teat and into your mouth. You barely noticed as your face pushed out and formed a muzzle with your new herbivore teeth as your arms and legs became equal length.
Your human mind was trying to protest but it was fading as your mind was being replaced by that of a foal wanting to feed from their mother's teats. You finished feeding as you pulled away from your mother and walked forward on your wobbly legs, your mother smiled and nuzzled you gently.
"Well, well Maria, you've got quite a nice little foal now," the attendant said as she looked in at you. "A shame, we could've used a new stud, but its admittedly pretty unpredictable. Lets see what we have here."
She entered the stall and checked you, finding out that you were a...