I have always banded at birth.. best to catch them the first day or two.. after that.. you will need to rope em. :) Many good suggestions here on what to do, but I say, make sure you have both nuts for sure.. and I have learned to either take a coffee can of feed with me to distract mama cow... or if she does get a bit riled... keep my shocker with me to let her know she wont be getting close to me. And do NOT take a dog with you.. EVER. Unless it sits in the truck and behaves..
Most of my cows are so tame, they dont mind me messin with their calves.. just have a few of them that get upset, but both the ways I described take care of that problem.