Thanks for the replys. I also prefer going late but feel i would be too late by the time i get back, could be 30hrs after end of standing. I've often wondered about going early. I have gone early before but right on onset of heat and had success. Never before heat though. As luck would have it when i drove in this morning she was jumping the others. So i inseminated her just now, mid afternoon. I still think it was to early and had a tough time unable to get through cervix. It is a heifer and she is the result of the very last a.i. i did until a few weeks ago so been a big break so feeling a bit rusty. Used a couple of bulls last year. Not feeling confident but trying to tighten up a group for calving.