The friend we are purchasing for Secret is not her future mate. I had considered that option, but Cliff wants Secret to have a pure Jersey calf. The lady who sold Secret to us offered us use of her bull, when the time comes.
Jersey heifers often start coming into heat by the age of six months. They shouldn't be bred before the age of fifteen months. Therefore, if we didn't castrate the bull calf, we'd have to keep the two of them separate to prevent a too-early pregnancy. And let's face it, that would defeat the purpose of getting Secret a friend. We'd have two lonely bovines around.
I certainly hope this answers all questions. Any further queries will be answered in email.