Boss animals. What am I doing wrong?

[Gold♥Shield]

I know you have to break the middle gauge before you can start to use tranquilizer arrows on them, but I've tried numerous times with several different level 100 characters but no matter what I do, I can only get their stamina gauge about a third of the way down before I completely run out of tranquilizer arrows.

The last attempt was with a level 100 Zhao Yun, the Demon Ex bow, and the accessory that gives +160 to bow skill as well as the one that increases my bow attack speed. I put gems in every slot that increases projectile damage as well and after all 83 tranquilizer arrows, the stamina gauge wasn't even halfway. I've seen a few videos of people doing the same thing with the same officer, but their tranquilizer arrows were knocking off huge chunks of the stamina bar.

Also, I feel I should say that I am breaking the middle bar with normal attacks before switching to a bow and all of my arrows are head shots for higher damage.

So, what am I doing wrong here?

[Stormy]

I've used level 100 Guan Yinping without any bow skill up stuff and using the Qilin bow EX and it worked for me.
Maybe trying using the Qilin bow EX and see if that helps. It shoots out a spread of arrows so it might actually be more effective than the Demon EX bow. Usually takes me about 60ish Tranq arrows to capture a boss.

[Gold♥Shield]

I dropped the difficulty down to easy yesterday and managed to get the stamina bar down to half with all 99 arrows, but today during the increased tranq arrows thing, I was able to capture it after using only 53 and a level 100 Guan Yu.

I'm not sure what's going on, but I've seen a few youtube videos where they capture the Revisited version on Chaos and manage to capture it in three or four cycles.