Best way I find to tame a bronto high or low lvl is to hit it one time and kite it to a cliff then pepper it with trank arrows

Simply find a sizable cliff and get it to chase you to it, then start pumping it full of Bill Cosby's special nectar

Brontos are a bullet sponging machine if found with correct base health and melee you will make raiding easier can get 150 Brontos to around 70k health and swiping it's tail can destroy x seeds hella quick

Caution: does not take 2 Tranq arrows with a crossbow. Many survivors died to bring us this message