Sassy2899 said:
Thank you all for the comments. I don't really know much about CIDR's, how do they work? How do you put them in? How long should they stay in? etc.
So there are a couple of different CIDR protocols out there. Some people swear by theirs more than others. This is the protocol we use, and have had a lot of success using. It is one of the more commonly adopted protocols.
Day 1, We give a shot of 2 cc's of GnRH (you will hear this referred to as GnRH or possibly Gonadotropin, the GnRH drug we use is Cystorelin). Also on day 1 insert a CIDR into the vagina of the animal using a CIDR insertion gun. Here is a good video on the process of inserting a CIDR.
http://dotsub.com/view/d970121a-6d78-4c34-b7bb-50872b6fc748
On Day 7 we pull the CIDR and give a 5 cc shot of Lutylase (this is the drug that is referred to as PGF2a or PGF2 alpha) Lutylase is probably the most common PGF2a used. After pulling the CIDR and giving the shot of Lutylase, you should have heat withing 48 - 60 hours. In my experience heifers usually happen earlier than cows. If you see standing heat, breed off of your normal rules behind standing heat. If you do not see standing heat breed the animal at 72 hours post CIDR. It isn't a must but we usually give a 2nd shot of 2 ccs of Cystorelin at this time. I have had a lot of success breeding off of timed AI like this where you never see standing heat at all.
As far as how it works the reproductive piece behind it is this, and skip this paragraph if you don't care. You give the first shot of GnRH on day 1 which clears the dominant follicle from the ovary. This is the point where you essentially start from scratch with the animal. You insert the CIDR which is progesterone. In a normal estrus cycle Progesterone levels spikes rises and then right before estrus it falls off dramatically. With the CIDR you spike the progesterone level and create a new 7 day corpus luteum. You pull the CIDR which drops the progesterone level, and give the PGF2a which causes your 7 days corpus luteum to regress. Estrus should occur at this point. You breed the way of the standing heat. As I said you don't have to give the 2nd shot of GnRH, however we do. Without giving GnRH you could possibly have a persistent follicle on the ovary where the cow is continually coming into heat every 7-10 days.
The CIDR protocol above works fantastic for me. I use it to be able to breed cows on the weekend (I work during the week). It also allows for a tighter breeding window.
You have to ask yourself a couple of questions to determine what you want from your herd to determine if June is too late for you to be calving. My cut off for me is usually around June 15. I am not a huge fan of June calves, but I AI everything so sometimes it winds up that way. (I had two this year) I will not breed for July or August dates simply because I don't want cows calving in 100 degree weather. It is too hard on them and me for that matter. If you breed today you are looking at a calf around May 25. So if you would use the CIDR protocol listed above you would get into June pretty easily. Around here we commonly have a May/June yearling class so May and June babies are marketable, but it varies by area.
There is other protocol where you can bring animals into heat quicker using just Lutylase, but it is not as reliable as the CIDR + Lutylase method.
Hope that helps.
