A little story on why I would castrate your calf
Buddy the (dairy) Cattle Dog
Back in the early 80's when they were known as Queensland Heelers we had a litter of pups, we sold all the females but could not sell the single blue male pup we had. Well I had gone to school with a kid, Jake, whose family had a dairy outside of town said he would take him off our hands and see if he worked out, but if he harassed the cows he'd fined himself taking a long knap in the river bed.
Well Buddy had not had his tail docked as a pup and it was quite the tail, he would wave it at the cows as he ducked under the fence after harassing them (he never did make it the river bed, but we'll get to that) Buddy was helping Jake move cows to get preg checked and got himself in a tight corner, he dove under the fence and almost cleared trouble when he came to a sudden stop. One of the big old play toys had stepped on his tail, breaking it at in half, the vet finished it off for him after preg checking the cows. It seemed to take him about a week to find his balance after that.
Well Buddy's favorite game was to run through the pens and grab a cow's tail, swing way up in the air, then let go just before he came to a stop and fly. Jake was pushing cows from the pen to the milk parlor and Buddy was up to his old trick of flying when Jake was suddenly charged by the bull that was in the pen with the cows. The bull had Jake pinned up against the fence and would have likely killed him had it not been for Buddy. Buddy had come from nowhere, first striking the bull full force broadside, and before the bull could blink, Buddy had him by the nose and pulled him away from Jake. Jake was able to scramble away and get out of the alley. Buddy let go of the bull and went to fly some more.
What does this have to do with your Jersey bull; Jake bottle fed this bull, he was his pride and joy, he was the beginning of Jakes Red Holstein herd. Jake had shown him as a Jr. Bull at both the county and state levels, he had spent hours upon hours with this bull, washing, leading, and grooming him. The day the bull attacked him was the first day he showed any aggression; he attacked with no warning what so ever and had intended on killing him.
Castrate your bull, find some beef cows/heifers or even some dairy/beef crosses and AI for beef calves, you will be ahead in the long run. My friend, Jake had been around cattle from his first days on earth, he knew the dangers and how to avoid them, he let his guard down once and it nearly cost him his life.