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United States Department of Agriculture

Agricultural Research Service

Title: Frequently Asked Questions About Synchronizing Estrus and Ovulation in Beef Cattle with Gnrh

Authors
item Whittier, Jack - COLORADO STATE UNIVERSITY
item Geary, Thomas

Submitted to: Virginia Cooperative Extension Publications
Publication Type: Proceedings
Publication Acceptance Date: February 15, 2000
Publication Date: February 15, 2000
Citation: WHITTIER, J.C., GEARY, T.W. FREQUENTLY ASKED QUESTIONS ABOUT SYNCHRONIZING ESTRUS AND OVULATION IN BEEF CATTLE WITH GNRH. VIRGINIA COOPERATIVE EXTENSION PUBLICATIONS. Beef Producers University-2000 Current Methods in Reproduction. p. 51-64. 2000.

Interpretive Summary: Gonadotropin Releasing Hormone (GnRH) is the master hormone of reproduction that comes from the hypothalamus. Pulsatile release of GnRH is required for the initiation of puberty and the return to cyclicity following calving. GnRH is currently being used with three similar estrus (Select Synch) or ovulation (Ovsynch, CO-Synch) synchronization protocols. Each of these protocols includes an injection of GnRH on d 0 and an injection of prostaglandin on d 7. With the Select Synch protocol, cows are observed for estrus from d 6 to 12 and artificially inseminated (AI) 12 h after detected in heat. With the CO-Synch and Ovsynch protocols, cows receive a second GnRH injection on d 9 and are AI on d 9 (CO-Synch) or d 10 (Ovsynch). The paper includes such information as the sources of GnRH that are commercially available to producers and their costs, when ovulation will occur following the GnRH injection, how these GnRH systems are different than other systems including comparisons with other systems, and tips to improve success to these systems.

Technical Abstract: Gonadotropin Releasing Hormone (GnRH) is the master hormone of reproduction that comes from the hypothalamus. Pulsatile release of GnRH is required for the initiation of puberty and the return to cyclicity following calving. GnRH is currently being used with three similar estrus (Select Synch) or ovulation (Ovsynch, CO-Synch) synchronization protocols. Each of these protocols includes an injection of GnRH on d 0 and an injection of prostaglandin on d 7. With the Select Synch protocol, cows are observed for estrus from d 6 to 12 and artificially inseminated (AI) 12 h after detected in heat. With the CO-Synch and Ovsynch protocols, cows receive a second GnRH injection on d 9 and are AI on d 9 (CO-Synch) or d 10 (Ovsynch). The paper includes such information as the sources of GnRH that are commercially available to producers and their costs, when ovulation will occur following the GnRH injection, how these GnRH systems are different than other systems including comparisons with other systems, and tips to improve success to these systems.

Last Modified: 10/22/2014
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