"Damn, Jude, why do I keep bulling out?" Zeb asked as he walked into the barn where Jude was showing Chad the milk carton.
Jude looked up and suppressed a smirk, "You know, Zeb, last time you changed into a bull, it was over two weeks afore you changed back," he said rubbing the whiskers on his chin, "an' the time afore that it was a full week, and 4 days the time before, and two days the time 'fore that. Seems like you is doubling your time as a bull. Think it'll be a month this time?"
Zeb bellowed in answer as his transformation progressed faster than before. The nubs on his head erupted into full horns, as his clothing was literally shredded, as his bovine body expanded inside his human clothes. He fell forward on his fore hooves.
Jude shook his head, "Reckon it'll be at least a month. Prolly, ought t' brand you? Seeing as how it won't take more than a week to service Chad and the other cows, I should ship you to the Husbandry Clinic to get your sperm collected and sold to other farms before you start to change back.
"Nuh mwand!" Zeb bellowed, he was already trying to nose open the stall to Chad's pen. Damn, it's all Chad's fault, he thought, that cowboy's scent makes me so horny.
"Oh, I'd never band you, brah," said Jude in reply.
"Mwand! Nahbamd!"
"Oh, you don't want to be branded. Well, I suppose I could use the ear tag and paint a temporary mark on your hide before shipping you to Sperm Central?"
Zeb just moved in reply, and gestured with his horns to Chad's stall gate.
Jude opened the gate, and let Zeb in. He figured they'd be a while. So he headed back to the house to cleanup the breakfast dishes.
Upon entering the kitchen, Jude was surprised to see Zeb's breakfast was untouched. He smiled, Zeb changed without eating the herbs that Jude had spiked the cereal with this morning. Bull soon would be Zeb's default form. He looked at the oatmeal, and frowned. Seemed wasteful to throw it out, and there was no way he was going to eat it. He'd think of something.
A few minutes later, Jude emptied Zeb's oatmeal into Chad's feed trough. Zeb would be hungry when he uncoupled