A.I. Synchronization Protocol-Combined Natural Heats and Timed

Help Support Steer Planet:


Well-known member
Dec 29, 2008
I am trying a little different A.I. synchronization protocol this year that combines both breeding A.I. off natural heats and synchronization using both visual standing heats and timed A.I. and using NO CIDR's.

1. Watch cows for visual heats for a minimum of 21 days.  A.I. breed normally, 12 hours after standing heat.  Inject 2cc of Cystorelin at time of A.I. breeding.

2. Day 0-Sort and inject of cows in herd/group, NOT bred artificially, with 2cc of Cystorelin (or which ever GnRH product you prefer).  No special time of day.

3. Day 7-At 8pm, inject cows NOT bred artificially in herd/group in the last 21 days, with 2cc of Estrumate (or 5cc of Lutalyse).

4. Watch for natural heats for the next 60 hours, A.I. breeding cows normally, 12 hours after standing heat, and injecting with 2cc of Cystorelin at time of A.I. breeding.

5. Just PRIOR to 60 hours past injection of Estrumate or 8am, watch/check cows for visual signs of heat.  Sort cows in standing heat to breed later. 

6. AT 60 hours past injection of Estrumate or 8am, A.I. breed all cows showing no signs of heat, based on "Timed Synchronization".  Inject with 2cc of Cystorelin.

7.  Any/all cows that were in standing heat, 60 hours past injection of Estrumate at 8am, breed 12 hours later at 8pm.  There is NO NEED to inject with Cystorelin again.

Any thoughts or others experiences that have used similar protocols?


Active member
Nov 14, 2017
You might be able to do less work checking cows for the 21 days


  • C521FB9C-0D16-40E9-855A-0938D3D2A0DF.png
    627.3 KB · Views: 281


Well-known member
Mar 5, 2007
This has worked well for me. heat detect and breed for seven days, on day 8 shoot with estrumate, heat detect and breed off of the observed heats, usually 48 to 72 hours later. it gets most of them and lowers the times through the chute and costs of drugs.