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Compliance of Hormone Injections for Timed A.I.
By Dr. Ray Nebel, senior reproductive specialist – Select Sires field services

Do you give all the hormone injections to cows that will receive timed-A.I.? For many of you, the answer is NO. Then the next question is: Do you know that every cow you time A.I. received all the correct hormone injections by the correct schedule? For cows on the Ovsynch protocol, this involves three injections starting with a GnRH injection, followed seven days later with a prostaglandin injection, then 48 to 72 hours later, a second GnRH injection prior to insemination. It is critical that every cow receive the right hormone injection on the right day. This insures that a follicle is ready to ovulate following the last GnRH injection prior to the insemination of highly fertile Select Sires semen.

What are your choices? Outside of giving all the injections yourself, the next best thing is to review with the individual that is giving the injections the importance that each cow on the injection list is injected correctly. Some herds use a marking system whereby the person injecting cows puts a mark on the cow so the technician knows the cow was injected. The most common system occurs when Co-synch is not being used whereby the final GnRH injection is administered 12 to 16 hours prior to insemination. An example I have seen is painting or chalking a yellow triangle or “G” on the upper loin area where it will not be easily rubbed off. This identifies that she did receive the final GnRH injection.

To check compliance, a blood sample must be collected the day of insemination and again two weeks later. Progesterone concentration is determined in both samples. The first sample (taken on the day of breeding) should have a low concentration of progesterone and the second sample (taken two weeks later) should have a high progesterone concentration. This testing is after the fact, but can be used to demonstrate that compliance is or is not an issue and what action needs to occur to improve conception rates.

Compliance is defined in the dictionary as to act in accordance with request, commands, requirements or conditions. Many times we overlook compliance as the reason for low conception rates in a timed-A.I. program, but you can only get a cow pregnant if she produces a viable ovum and if the injections are not given to the right cow at the right time, you have no chance of this happening.

Work with your NorthStar Cooperative Reproductive Solutions Specialists to get the most out of your breeding program. Click here for more information on progesterone testing.