The 2nd shot is usually given on day 11. Just curious, why aren't you using co-sync including cidrs? Quite a bit more predictable as to when they will cycle with the same amount of times through the chute. I saw yesterday that SEK had cidrs advertised for $8 and 20 some cents a piece, which would be the approx extra cost. I have had excellant luck with this program. I target for a Sunday main event as to when most of the cows will be standing, which means that you need to put the ciders in on a Thursday 6pm time frame , pull ciders a week later @ 6pm along with a shot of lute or estrumate @ the same time. When you put your cidrs in you need to shoot with GnRH. You will need to be watching Sat evening for any early heats, but pretty much Sunday morning will be busy sorting cows off. I have had great luck with this with my own herd and others that I breed for. I do not time breed in my own, but do for others depending on how good of a heat detector I am working with has great bearing on these decisions. Some people will breed any non responders @ about 72 hous after pulling cidrs if there is no response. I don't in my own because I will just wait them out. The percentage is low as far as non responders. I hope that this helps you decide what protocal is best for your situation. Cab