I've always used live cover on my cattle. (except for some beef cows my kids raise show calves out of). I just usually rent a bull for about three months a year. This way, I'm not feeding him all year and my cows stay pretty well in sync to all calve out in the three month window. So far, this has worked well for me. I've never bred my mini jerseys to a mini jersey bull. I've always used a full size jersey and I've gotten very small calves out of them which is typical for most jerseys. Mine must have a particularly small strain in their bloodline, because all the calves are growing up to be minis as well. Last year I used a Milking Shorthorn bull to get some more teat length (I knew the udder confirmation history on the specific bull I was using.) and I've been very pleased with the calves. They're deep red in color. They have ever so slight black highlights on their muzzle, nose, and eartips. And, they seem to have a real good disposition with some brains. The heifers have haltar broke nicely.