Found 2 spawns of cows today and have been having issues trying to tame them

I have all the skills needed to do it and know how to, trouble is when taming for the first time, running away and returning to aggro a different target before switching to original target often it does not seem to work. Either it lets me quell a few more times then resets back to 20% or it is constantly stuck on 20%.
I've even tried waiting (without doing the run away thing) but sometimes the animal stops twitching altogether so 1) I can't tell when it is safe to attempt a skill (sidestep etc) or 2) I wait for a long time and it does not reaggro me.
Is there a special way to tame animals or is the buggyness normal?
Thanks!