Stegos have the new tlc which means in the wild they will have about a 50% damage resistance which will make it harder to knock out. With the info on knocking it out (how much it takes) multiply it by 2 to make it accurate to how much you need to knock it out! Hope this helped!
They are mildly slow, but you might want to get on a rock and shoot it with tranq arrows, takes 2-5 arrows and make sure you have bio toxin on you. Takes a while for them to tame, the best thing to beat that time is to get a sleeping bag ( Not a simple bed!) And sleep in it. When you wake up shove a hundred bio toxins down it's throat, wait that three more minutes, and you got a stego.