We have begun to synchronize our sheep breeding season with the use of a CIDR (Controlled Internal Drug Release). A couple of years ago I had a ewe that did not get bred the previous season. A friend and fellow shepherd suggested that I use a CIDR to force her into estrus. A CIDR is a applicator that is inserted into the vagina of the sheep. It contains 0.3g of progesterone. Progesterone is a naturally occurring hormone which suppresses estrus. By inserting a slow release of progesterone into the vagina, estrus is inhibited until the applicator has been removed. Upon removal, the ewe will experience a drop in progesterone which will trigger her estrus cycle. With the use of the CIDR, my ewe got bred that year. Though CIDRs are mainly used for prepping ewes for artificial insemination, there are other reasons shepherds may choose to use them.
Reasons to use CIDRS:
- Synchronize ovulation in your flock of ewes thus narrowing the lambing window
- Out of season breeding
- Support a ewe that was missed in the previous breeding season
- Prepping ewe for artificial insemination
- Shorten amount of time the ram is in with ewes
Using CIDRs has made a tremendous impact on our breeding and lambing routines. In Vermont, we are often breeding during snowy months. I often have 3 or 4 breeding groups all in need of separate quarters. This becomes challenging once snow falls as electric fencing is not as effective. Maintaining multiple breeding groups in the field becomes almost impossible once snow falls and temperatures fall below freezing. By using CIDRs, I am more confident that the ram has bred his ewes in a shorter period of time and I often shorten the time the ram is in with the ewes. The biggest benefit we have felt, has been the ability to know within a day when our ewes will lamb. Now that my children are all gone from home, it is nice to have a smaller window of time when lambs arrive. My husband can plan to take off work for a couple of days and l have an extra set of hands when ewes go into labor. Though I was hesitant at first to use CIDRs, it has helped us be more prepared and have a more productive lambing season.
Inserting CIDRs in Sheep
Here is a wonderful video on the proper way to handle and insert CIDRs.
Learn more about preparing for breeding season:
Where to Purchase CIDRs (Make sure they are CIDRs for sheep and NOT cows as the progesterone level is different for cows!)
