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Cattle breeding programs researched

Posted 5/1/2008

UNCE releases fact sheet about beef cow and heifer insemination

University of Nevada Cooperative Extension (UNCE) has released a fact sheet describing the development of heat synchronization protocols that help increase pregnancy rates of beef cows and heifers. It is available for free and online at

Ron Torell, UNCE livestock specialist, and three Western state specialists constructed a report about the development and use of the controlled intravaginal drug releasing device (CIDR) and gonadotropin releasing hormone (GnRH). It has allowed producers to manipulate the estrous cycle and ovarian activity of beef cows and heifers.

"Incorporating natural service into a timed breeding AI (artificial insemination) program can boost conception rates as much as 20 percent," the fact sheet said. "This will increase the number of calves born early in the calving season, thereby yielding more pounds of calves to sell at weaning."

The fact sheet describes the most recent protocols and developments and incorporates them into a natural service breeding program in conjunction with artificial insemination. The fact sheet includes an examination of two protocols involving yearly replacement of heifers.

For example, the first protocol used CO-Synch + CIDR with exposure to fertile bulls from time of CIDR removal to 48 hours and again at 84 hours. The second evaluated the CO-Synch protocol without a CIDR. Two figures are included to supplement statistics.

For more information, visit and click on the publications tab and search "artificial insemination" under the title category.

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