We're always looking for ways to increase our AI conception rate. Through the years we have tried several different estrous synchronization protocols in an effort to get more AI pregnancies. This year we decided to try a technique called reCIDR with our summer calving cowherd. If the technique is successful we plan to use it next year on all the cows.
To start with we used a standard 7 day CIDR protocol. When we pulled CIDRs we gave each cow a dose of Lutelyse and placed an Estrotec patch on each cow. After pulling CIDRs we used split time AI to breed the cows. 66 hours after pulling CIDRS we bred the cows whose patches showed signs that they had been in heat. The 'colds', or cows with no signs of estrus on their heat patches at 66 hours, were bred at 90 hours after the CIDRs were pulled.
On day 5 (4 days after breeding) we turned one bull out in each group of cows. Each cow group had around 90 cows. The bulls were pulled from the groups on Day 13 and we put a CIDR back into all of the cows.
On day 20 (19 days after breeding) we pulled all the CIDRs and placed new heat patches on each cow. We then rode heats and bred for 4 days. On day 26 (after the initial breeding) we turned the bulls back out into their groups where they will stay until day 45.
The thinking behind reCIDRing is that we will be able to identify, synchronize and breed the cows that didn't concieve on the initial AI breeding, without disrupting the pregnancies of the 50+% of cows who concieved during the first split time AI. Being able to AI without waiting until the next heat cycle or pregnancy ultrasound will help us have a tighter calving group, more AI pregnancies and use less clean up bulls.
While there isn't much research on reCIDRing everyone we talked to believed that the progesterone shift from placing and pulling a CIDR in a bred cow wouldn't disrupt the pregnancy and in theory the reCIDR would be effective. Our initial impressions is that the reCIDRing seemed effective. We AIed under 50% of the total cowherd the second time and so far the bulls have not seemed overly active. We will share our results after we ultrasound!
If you have any questions about how we used reCIDRs feel free to call Craig Bieber 605/216-8169 or Craig Howard 605/377-3128.