Mildot is the way to go as a couple have already mentioned. No battery problem and you can memorize your holdovers which is very fast if needed. I'm using the MP8 which is close to the best so far as you can see clearer and have the 1/2 mil marks and now I know my holdovers up to 700 yrds. As for animal size I know the size of the ones I hunt so that makes it easier to range as well.
This is the standard MP8 with up to 10 mils of holdover.
Here's the new version with 15 mils of holdover WOW!
With either one you can holdover pretty darn far.