[You MUST have a mated pair of Spino's, level 200+ post tame/bred]. Make a small to medium sized taming pen. Lead or drop the Troodon in the pen. Breed your 2 high level Spino's. Time it so your fertilised egg hatches at night. Then place the baby Spino on neutral and drop it in the Troodon pen. Jump in the pen and sacrifice yourself next to your baby Spino. The Troodon will kill you first and then your baby Spino. Repeat for the opposite gender and never worry about taming them again.
At lvl 72 with flak armor on, a lvl 5 Troodon knocked me out with one attack at night. Last thing I saw was those glowing eyes before passing out. My Guess is that they attack vital organs. Luckily my Doedicarus was up for a game of baseball and launched that little devil out into the stands.