ARS | Publication request: FREQUENTLY ASKED QUESTIONS ABOUT SYNCHRONIZING ESTRUS AND OVULATION IN BEEF CATTLE WITH GNRH

Submitted to: Iowa Cooperative Extension Publication
Publication Type: Proceedings
Publication Acceptance Date: January 15, 2000
Publication Date: March 1, 2000
Citation: WHITTIER, J.C., GEARY, T.W. FREQUENTLY ASKED QUESTIONS ABOUT SYNCHRONIZING ESTRUS AND OVULATION IN BEEF CATTLE WITH GNRH. IOWA COOPERATIVE EXTENSION PUBLICATION. 2000. p. 51-64.

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.