I've had a couple of Vets tell me that this has been a hard year to heat detect in Iowa (especially during June, July) because of the heat. I had 5 cows not coming in even after 60 days post calving and a round of shots of Lutylse. My embryologist said to give a shot of cystorylin and insert cidr on day 1, pull cidr and give shot of Lutylse on day 8, give another shot of Cystorylin AND breed on day 10. I did as he told me, only saw one cow in standing heat, but bred the other 4 on day 10, and haven't noticed any activity since. Three of the 4 did have tons of mucus when I was breeding them, so I assume they had a good heat cycle. I put them with a bull 30 days later, so we'll see if ii worked.