Sophie finally recognized the dark shape before her, the farms bull Buster stood over her, his fur coal black and his head crested by two enormous horns. Through her hazy mind Sophie paid no head to the potential danger and instead found herself staring at the bull's penis as it hung limp in front of her while he sniffed her hair.
After what felt like an eternity Buster gave a loud huff of approval, having now determined that the intruder in his stall wasn't a threat, her scent instead marking her as a fertile cow. Before Sophie's eyes the bull's cock began to slowly pulse and engorge as he made ready to mate.
Still fighting the haze clouding her judgement and now locking her body in inaction Sophie was only dully aware of Buster as he moved around behind her. It took her several seconds to realise what he intended to do and that perhaps facing her fully exposed and visibly throbbing nether regions towards the clearly aroused bull wasn't the best of ideas. Before she had a chance to act on the thought however the moonlight was cut off by a dark shape as Buster positioned himself over her, his fully erect member now bulging at full mast.
As a huge, meaty mass began to poke around her still slowly swelling rear Sophie fought through the haze over her mind, willing her body to move before it was too late. "Uenghh no... Bus... Buster... I'm not a cowwwww!" Sophie only made it partway through her feeble protest before she was interrupted by the sensation of her lower lips parting as Buster found his mark and with a squelch proceeded to bury his cock as deep as it would go, driving the breath from her lungs.
Gasping for air the haze over Sophie's mind was gone in an instant, the control over her mind seemingly no longer needed. Snapping back to reality Sophie was greeted by the sensation of her impossibly stretched pussy desperately milking at Buster's girth. "Oh!... Fuck!... No!..." she screamed between thrusts as he began to move back and forth, settling into a rhythm as he began mating with her.
Completely dwarfed by Buster, Sophie had no chance of escape, despite her disgust at her current situation she couldn't deny her unnatural desire to continue as her body buzzed with excitement.
Bracing her hands on the barn floor Sophie was helpless as she watched her breasts flop back and forth with the force of her breeding, the haze gone Sophie almost immediately noticed that they were close to double their previous size and that her body was clearly undergoing some sort of transformation.
It occurred to Sophie that Buster shouldn't even be able to fit inside her "eughh, howww... what the hell... did that rock do to me...", she managed to moan between thrusts as waves of pleasure surged through her body.
As precum started to leak from Buster's cock Sophie's already drooling vagina began to audibly squelch with each of his thrusts. As her entire body burned with arousal something in Sophie finally snapped, unable to hold back any longer she began to match Buster's thrusts, his swollen balls slapping into her swelling ass every time he pushed into her, the sensation sending shivers of excitement down her spine as he seemingly went deeper and deeper each time.
Within Sophie her changing body had begun to absorb the juices leaking from Buster's cock, the bovine dna already starting to meld with her own as the strange power made ready to mutate her into a form better matching the barns bovine inhabitants. Slave to her lust Sophie only realised the true nature of her situation when the inevitable happened and the bovine dna inside her reached it's tipping point and her transformation proper began.