Does anyone use timed breeding? We've done it for the last 3 years( gnrh, cidr, lute than gnrh at time of AIing, I think heifers at 54 hours and cows at 60. We didn't heat check at all, this year we hit 80% on the cows but heifers are at 50%. Typically we have been 60-70% on the cows, this year...