One issue with Kamars is that some of them will completely break and you're not going to find that cow in a pasture of 150 cows.  The Kamar will still be white if it breaks open.  If it's not red then you won't see broken Kamars unless you gather all of the cows morning and night.  Also, those Kamars that never really turn red but are just pink.  Is it a bad patch or what?  It's hard to know.  We have always bred those pink patches.  Missing a couple of cows in estrus of several hundred really doesn't matter all that much, but you want to do everything you can to get proper heat detection.  It's labor intensive to be out there breeding and heat detection is the most important part.