If you have any trees or anything cows can rub on I would stay away from estrotect. You will have a bunch of patches scratched off from cows rubbing on things......not real jumps. I have had the best luck with KMARS. I hardly ever loose one and don't ever get any false reads. It takes constant pressure for the red die to release into the patch to make it red. The estrotects are just a big scratch ticket that usually doesnt pay off for me. When the Kmars are red you are 95% sure they are standing, when the estrotects are red I would say if your not their watching them you are more like 50% sure its standing heat. If your watching the cows fairly decent the Kmars will only turn slightly red the first hour of jumps. Then when they are red solid you know they are standing good. Then I always breed 2 times a day. If they are starting night, I breed the next am. If they are starting to stand in the am, I breed them that evening. Then the ones that come in midnight, midday I seem to roll the dice and just pick one or the other and have never found a good one to do.