RE: Do I need more Knockdown Power?
I would guess you have a dead deer out there some where. That would be plenty of power especially at the range you mentioned, and a great bullet to boot. It makes me think your shot placement could be better. I suspect if you aimed for the front shoulder, you probably hit it, and broke it, knocking it down. The problem could have been the bullet expanded a great deal and lost a lot of its power and might have only reached one of the two lungs. Once the deer got their bearings and a shallow breath, they were off. You also probably did not get much of a blood trail because the blood would pool first in the lower lung and chest cavity before reaching the entry hole.
If you did not push the deer hard, it would have run off and layed down somewhere close. I would go back to the spot where you hit the deer, and look for blood sign. Especially a couple feet off the ground on bushes. Look for the animal's track.And are good at tracking, cut a tracking stick and have at it. If you find no sign, then start walking circles, lookiunder brush piles, and behind logs because I would guess that doe is laying somewhere within 200 yards of the spot you shot.. if you did not jump her trail and push her right away.