As the scent grew weaker and the sounds of the cow's hoofsteps grew more distant, the bull stood tensely and then gradually started to calm down. It remembered who it was--who HE was.
"Oh, man, that was crazy. I totally lost it back there!" thought Bryan, quivering slightly in his stall. Sure, he'd zoned out many times and carelessly followed his new body's instincts, but never like that. He had resisted fertile cows before, but this time, he caught one whiff and then he simply WAS a BULL! It was getting harder and harder for Bryan to resist the things a bovine was driven to do. For that matter, it was getting less common for him to even notice and object to the increasingly bullish aspects of his daily routine, he realized, belatedly noticing that he was peeing again in his stall as though it were the most natural thing in the world. Doing his business wherever he stood was just his way of life now. If he hadn't resisted this long, having sex with animals would probably have become his way life by now, too.
"If I hadn't been caged in, I would have mated that cow," he realized, disgusted with himself, his dick going back in his sheath. He couldn't help but think it might actually be a good thing that the vet was collecting his cum artificially. "I can't resist these instincts much longer, and it doesn't look like I'm ever changing back," he thought dejectedly. If the vet could at least finish the semen collections and castrate him as promised, he wouldn't have to fight his body's sexual urges any longer. He would die in a slaughterhouse, but at least he would at least die with the dignity of only ever having had sex as a man.
Of course, it was hard to anything about dignity the next time he saw that electric probe. The vet and the farmhand talked about him like he wasn't there and laughed about having about their (presumably) gay stud lifetime of orgasms in a few days. As humiliated as he was to be talked about that way, he couldn't help but admit to themselves that they were right. He was in the prime of his life, experiencing all the sexual pain and pleasure he would ever have in this rest of his shortened life, right here in a controlled environment, on these humans' schedule. And in an oddly perverse way, he actually looked forward to getting that probe stuck up his ass again, at least to a certain extent. He was experiencing the longest and hardest orgasms he'd ever had in his life, and he wouldn't get to experience them much longer. Even if he was just cumming into a container so his farmers could impregnate their cows, he should bite the bullet and try to enjoy experience as much as possible, because his every orgasm could be his last.
The probe went in, the circuit was completed, and Bryan bellowed, feeling his fluid surging through his mighty shaft.