"Neeiiiiggh," The newly transformed mare said as you thrust into her vagina one last time and ropes of cum spurted out into her. That made another mare for the Stables successfully transformed as you dismounted her and nuzzled her gently, she looked a little sad as her head drooped a little, resigned to her fate as your seed dripped from her vagina.
You went over to a spot to graze as you looked over to see another stallion in the process of mating with Vicky. Your newest mare's former boyfriend had taken to it quickly, which got a sad look from the mare before she went to graze next to you. The two of them were the latest in a long line of people the two of you had transformed. The stallion was to be sent to a breeding farm while the mare was to join your herd. You had become successful enough that the attendants had given you a pasture to share with some of the mares you had transformed and bred.
The attendants arrived not long after as they started to lead the four of you back towards the Stable. You passed by a pair of women who were riding on Henry and another stallion, neither of them even aware of what fate awaited them. You nickered a little, kind of wishing that you had the chance with them, but maybe later if you were lucky.
"Come on Prince, you'll get to have fun with the mares later," the female attendant said as she patted your nose. "Come on, I think you've earned a break from transforming people. Let's get you and your new mare to the pasture."
You nodded your head as you were led through one of the gates to a pasture where many mares were already grazing. You stopped by Jessica where the white furred mare was grazing. You nuzzled her gently as you saw a colt down by her teat nursing. It was hard to believe that it had been a year since the two of you had come here, and your herd had already grown so much. Some of the other mares were already pregnant with your foals as they grazed, each of them having long surrendered to their fates.
You nuzzled the new mare a moment as she looked a bit nervous. The other mares came to greet her and welcome her into the herd. It was wonderful to have so many mares, you had no idea how you had ever lasted as a human.
"Good work, Prince," the female attendant said as she smiled and backed up a little. "You're going to do just fine out here. Another beautiful mare for the Stables. And good news, I think Jessica is going to go into heat again soon. You're quite the power couple here."
She laughed a little as she walked off. This was your life now and you weren't going to try and fight it. You just wanted to spend as much time as you could with your herd, this was a much better life than anything you could've had as a human.
You lowered your head to graze.