While it may still look like winter in most of the area it must be spring because it's the start of breeding season here at the ranch!
Last week Thursday/Friday we bred our 430 replacement heifers. The heifers were split into 4 groups and we used a standard 7 day CIDR protocol and time AI bred two groups on Thursday and two groups on Friday. Next week Monday/Tuesday we will reCIDR all of the heifers.
In 2016 we sampled the reCIDR method on our May/June calving cows and liked what we saw. So last year we decided to use the reCIDR program on all of the cows on the ranch. Using this method we saw AI conception rates of 76-80% over the two AI cycles.
How does it work? To start with we used the standard 7 day CIDR protocol and time bred all of the heifers AI for the first cycle. Then on Day 11 post first breed we re-inserted a CIDR into all of the heifers. Those CIDRs will be pulled on Day 18 post breeding. After the second pull we rode heats for 3 days and AI bred the second cycle. On the fourth day will turn out clean up bulls.
The thinking behind reCIDRing is that we will be able to identify, synchronize and breed the heifers that didn't conieve on the initial AI breeding without disrupting the pregnancies of the 50+% of the heifers that did convieve during that first timed AI breeding. The CIDR releases the hormone progesterone and it is believed that the progesterone shift that occurs from placing and pulling a CIDR in a bred animal isn't great enough to disrupt the pregnancy. Using reCIDR we are able to AI on that second cycle without waiting until the next natural heat cycle or pregnancy ultrasound which helps tighten our calving groups and also allows us to use less clean up bulls.
As always check with your veterinarian before adopting any new practices into your herd. If you have any questions feel free to contact Craig Bieber, firstname.lastname@example.org or 605-439-3628.