Take two: (bouncy internet connection)
What are you trying to do? Produce feeder calves; or are you trying to produce milk cows? If feeders was the route; than why are you going back to Jersey bulls. Your not going to get that great of calves out of one cross. You'll have to get rid of those jersey or keep working those beef genetics in for a few generation befor you have a nice set of calves.
TB-Herefords: A third of the cows that bull mated were Holstein-Friesian or mostly so, and the bulls of that breed and their beef crosses usually sell well here. Before bringing him in I'd done 5 weeks AI with dairy semen, and beef semen over the lower producing cows. That takes care of herd replacements.
Dang, I wish you could just read the very eloquent former post that got lost

I'm slowly breeding up with a view to maximising hybrid vigour, potentially moving to dual-purpose breeds but also trying to stay within the accepted industry limits for breeding top dairy cows. Angus is a compromise between easy calving and the potential of a few calf sales. I decided to go back to Jersey basically because I was pissed off at the fella posted above being sub-fertile, wasn't getting calf sales anyway (my stock agent has a habit of conveniently forgetting my animals) and another farmer voiced his opinion that dairy farmers were shooting themselves in the foot trying to cross to beef. I've since read around enough to learn that what he said doesn't hold true to Angus - Hereford are longer gestation and higher birthweight.
The most sensible route from here looks like doing 12-weeks AI, with short gestation Jersey semen over the Jerseys and short gestation Angus (that's what the Waigroup semen was) over the larger cows. Next year I'll probably be making the decision again - buy the semen and do the work of heat detecting and cutting cows out myself, or get bulls in with all the attendant risks. Haven't decided yet.
Unwanted calves get trucked off farm at four - five days old for veal. That's where my Jerseys and their crosses go, except for the AI-sired heifers. It's an alternative to shooting them.
Ah: Loch Valley Fold - yes, it's the twins that caused that. Hard year with drought last year and the herd weren't as fat as I'd have liked going into calving, but anything else that light would have been sick.
I hope the 'exactly like' photos is *only* the one of the AI-sired calves? I've seen some odd supposedly-Angus calves before, but nothing like these creatures.