She took the syringe and while the male officer tried to struggle he was held still and it was injected into his arm. She stepped back and smiled as the fur started to grow on his body as he looked back at the attendant who had brought the syringes.
"Go and get me the mare that transformed the would-be thief, its time she got her reward," she said and looked back at the soon to be stallion who was starting to balloon out into horse proportions.
"Yes ma'am," he said and headed back out into the stables proper.
In your stall your arousal is starting to drive you crazy, it doesn't help that you can smell the stallions around you making you more and more aroused. You could see the mare and stallion from last night getting more and more aroused as they tried to get at one another and that certainly wasn't helping matters.
Your human mind was protesting the idea of being taken like some common beast, but your horse body was crying out for it. Your vagina was demanding the attention of a stallion and it was overriding your human reason and when the male attendant came to take you away with promises of a stallion stud you didn't even resist as you were taken away to the back room where the officers had been taken before.
You found the attendant from before standing there smiling. Lying on the floor was a weird mix of a human and a black stallion, ropes and clothes were lying in tatters on either side of him while the female officer looked on terrified as her partner changed into a horse. His now massive horsecock was standing at attention and he huffed a little when he saw you, his face was pushing out into a muzzle already.
"I promised you a reward for what you did," the female attendant whispered in your ear as the stallion got to his transforming feet and moved behind you. "But we don't want to risk you injuring our new stud, so, Equestrian Life."
That simple phrase triggered something in your mind and pushed your human side to the back, it was still there but it had no control over your body anymore. Not that it mattered, you weren't about to fight back anyway as you pushed your tail to the side and you felt the stallion's muzzle up close to you while he smelled your pheromones.
The transforming police officer didn't need any further motivation as he mounted the mare, his human side was long gone as the full effects of the injection took hold. He could smell the mare's heat and that completely consumed him, he was going to impregnate her and any other mares he could find.
The female officer let out a muffled cry as her transforming partner thrust into the mare. She wasn't even thinking about the possibility that the mare had once been human, none of this made sense to her anymore. And it was starting to go through her mind that she was going to be next.
At this point the only thing left that reminded anyone that the stallion was once human as he thrusted deep into the mare was his still roughly human face and some patches of skin and his fingers still hardening. The mare neighed loudly as she was penetrated and she started to move with the thrusts as the stallion rested on her back, thrusting faster and deeper into the mare.
Your human mind was reeling, the sensations going through your body were hitting your brain at full force as the stallion continued to mate with you. Your horse mind was loving it, she wanted to bear this stallion's foals and had been driven crazy by the heat. Your mind was starting to agree, there was something extra exhilarating about this sex session now that you were more in control and could fully enjoy the sensation of mating.
Maybe it wasn't so bad after all, maybe you could get used to being a horse. You whinnied as the stallion thrust again, this time penetrating all the way to your womb as he thrust his now full length into you as his balls slapped against you. You couldn't see it but you felt his now fully formed muzzle and hooves pressing against you as he neighed loudly and thrust into you one last time, his seed spurting out into your vagina.
The stallion dismounted from you and you looked back to see him more antsy. The female attendant smiled and patted your neck. "Good girl Princess, he's a fine stud and is going to do great things for this Zoo. Take her back to her stall, and let Alan into Megan's stall, I think we've made those two wait long enough."
The attendant nodded and pulled you back to your stall. You took one last look back at the attendant who was getting the second syringe ready and looking down at the female officer who was terrified now, you knew she'd soon be a mare like you.
And you no longer cared.