JPJ calves typically come pretty small and easily. He is one of the most surefire heifer safe bulls out there and is the go to bull for numerous breeders when it comes to calving ease. However, just because I know its coming, I wont say he works on everything, just like all these low birthweight angus that everybody taunts on here dont work on everything. Remember the cow gives that calf half of its DNA material so you have to look at hers to, but I would say unless the cow is just an elephant as far as BWs go then you should be pretty sure fir safe using JPJ.