My experience with yellow jacket has been limited, but the calves I have seen aren't always the most moderate. Most of the heifers I have seen are moderate but the steers aren't always. One calf born out of yellow jacket last year was probably in the upper 90's. I do know one thing though, all the yellow jacket calves I have broke and clipped do not have mild temperaments. In fact I dread dealing with them. The steers get really big and may look good as babies but never really hold together. The heifers tend to do better. This is crossed with Maine and Chianina cows.