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Q. I have heard that a person can use a Controlled Intravaginal Drug Release (CIDR) device to bring late-calving cows into heat, breed them with either AI or bulls and that they will calve earlier next year. How does this work? (April 2017)
A. A CIDR will often induce estrus in cows that haven’t come into heat yet after calving. The CIDR is inserted into a cow’s vagina, where it releases the hormone progesterone. CIDRs are a common estrus synchronization tool, but they can also be used to bring cows into heat before they would normally come into heat on their own.
For this to work, the CIDR should not be inserted until at least 20 days after calving. The uterus must shrink back to its original size for reproduction to occur. Recovery takes time―imagine something holding a 90 lb calf needing to shrink to the size of a volleyball. Trying to “jump start” the cycle with a CIDR (progesterone device) too early after calving could result in less than desired pregnancy results.
If you plan to use natural service breeding, insert a CIDR for seven days, then remove the CIDR on day 7, and give an injection of prostaglandin. Bulls can be immediately placed with the cows. There is no need for extra bulls; a bull-to-cow ratio of 1:25 should be sufficient. Young bulls may require special attention and a higher bull-to-cow ratio.
This protocol requires two cattle handlings and will cost about $15 for the CIDR and prostaglandin.
Since the CIDR will synchronize estrus, you could also use artificial insemination (AI). If you choose to use AI, you need to
- add a gonadotropin-releasing hormone (GnRH) injection at the CIDR insertion,
- leave the CIDR in for seven days, and
- inject prostaglandin when you remove the CIDR.
If you plan to AI, it would be worth your time to look over the different estrus synchronization protocols at: http://beefrepro.info or visit with your AI representative or Extension Educator. Choose a system that works best for you. Any of the seven-day CIDR protocols will “jump start” the estrus cycle. The “recipe” for each system should be followed exactly—no guessing or giving late injections!
Cows should be in good condition, a body condition score of 5 or greater at the time of calving, and maintaining or gaining weight after calving through breeding. Cows maintaining or gaining weight are more likely to conceive and sustain a pregnancy than cows losing weight.
Bethany Johnston and Jay Jenkins
Nebraska Extension Beef Educators
How much water do cows drink per day? (July 19, 2016)
What does one do if one has a perennial problem with scours in calves? (February 17, 2016)
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