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Copyright © 2015
Angus Journal

Synchronization Protocols for Cows

FORT COLLINS (Dec. 2, 2008) — Development of estrus synchronization protocols has advanced at a phenomenal pace during his 40-year lifetime, reproductive physiologist Cliff Lamb told attendees Dec. 2 during the Robert E. Taylor Memorial Symposium: Applied Reproductive Strategies in Beef Cattle in Fort Collins, Colo. But, the latest generation of protocols uses two strategies key to more widespread adoption of synchronized artificial insemination (AI).

University of Florida Extension Beef Cattle Specialist Cliff Lamb discussed estrus synchronization protocols for cows.

“These strategies include minimizing the number of times cattle must be put through a cattle-handling facility and they eliminate detection of estrus by employing timed AI,” explained Lamb, who is director of the North Florida Research and Education Center. “High priority needs to be placed on transferring these current reproductive management tools and technology to producers, veterinarians and industry personnel to ensure they are adopted at the producer level and to provide the necessary technical support to achieve optimum results.”

Lamb attributed increased success of modern estrus synchronization protocols to incorporation of the CIDR® — an intravaginal progesterone insert used in conjunction with other hormones. Upon insertion, blood progesterone levels rise rapidly, reaching maximal concentrations within an hour after insertion. Concentrations are maintained while the insert is in place, but progesterone levels are quickly eliminated after removal.

Inclusion of the CIDR in the CO-Synch procedure is the most researched alternative and the primary timed-AI protocol recommended by the Beef Reproduction Task force for use in beef cows.

“Results of the most recent CIDR-based studies indicated that, for a timed-AI protocol, the five- or seven-day CO-Synch + CIDR protocols yield the most impressive pregnancy rates, whereas the Select Synch + CIDR and timed-AI treatment yields the best overall pregnancy rates,” Lamb said.

He said research has been conducted to determine whether the CIDR could be utilized to enhance reproductive performance in herds employing natural service. Insertion of a CIDR occurred seven days prior to the breeding season, with removal on the day bulls were introduced to the herd. Results showed no increase in overall pregnancy rates, but more cows conceived during the first 10 days of the breeding season.

The Robert E. Taylor Memorial Symposium is conducted by Colorado State University every other year to provide current, research-based information for improving profitability in the beef cattle industry. The ARSBC program was developed by the Beef Cattle Reproduction Task Force to improve understanding and application of reproductive technologies, including AI, estrus synchronization and factors affecting male fertility. In 2008, CSU and the Task Force collaborated to provide the Dec. 2-3 symposium in Fort Collins. To listen to Lamb’s presentation, view the accompanying PowerPoint or view other presentations from the symposium, visit the newsroom at

— by Troy Smith

Click here for accompanying PowerPoint as a pdf file (1.8 MB).
Click here for the audio of the presentation (4.9 MB mp3).

Editor’s Note: This article is available as a news release to redistribute per an agreement between the symposium hosts and Angus Productions Inc. Click here to submit a request for a high-resolution photo of the speaker. For additional information visit the newsroom of