Page Banner

United States Department of Agriculture

Agricultural Research Service

Title: Synchronization of Ovulation Using Hcg Or Gnrh with the Co-Synch Protocol in Suckled Beef Cows

Authors
item Salvorson, Robin - COLORADO STATE UNIVERSITY
item Whittier, Jack - COLORADO STATE UNIVERSITY
item Schafer, D - COLORADO STATE UNIVERISTY
item Schutz, D - COLORADO STATE UNIVERSITY
item Downing, E - COLORADO STATE UNIVERSITY
item Polmeroy, T - COLORADO STATE UNIVERSITY
item Geary, Thomas

Submitted to: Beef Research Report
Publication Type: Proceedings
Publication Acceptance Date: April 1, 1999
Publication Date: April 1, 1999
Citation: SALVORSON, R.R., WHITTIER, J.C., SCHAFER, D., SCHUTZ, D., DOWNING, E.R., POLMEROY, T., GEARY, T.W. SYNCHRONIZATION OF OVULATION USING HCG OR GNRH WITH THE CO-SYNCH PROTOCOL IN SUCKLED BEEF COWS. BEEF RESEARCH REPORT. COLORADO STATE UNIVERSITY. 1999. p. 69-74.

Interpretive Summary: Primaparous and multiparous cows (n=467) from two locations were used to evaluate the effect of 48-hour calf removal and the use of human chorionic gonadotropin (hCG) in place of GnRH with the CO-Synch protocol. Treatments included GnRH, GnRH + calf removal, hCG, and hCG + calf removal. Pregnancy rates were higher (P<.05) for GnRH treated cows (48%) compared to hCG treated cows (34%) regardless of calf removal. Calf removal had no effect (P>.1) on pregnancy rates. Cows that received hCG had a higher (P<.05) incidence of short cycles following timed AI and a higher incidence of persistent corpora lutea at the time of insemination. We conclude that hCG is not a suitable replacement for GnRH with the CO-Synch protocol.

Technical Abstract: Primaparous and multiparous cows (n=467) from two locations were used to evaluate the effect of 48-hour calf removal and the use of human chorionic gonadotropin (hCG) in place of GnRH with the CO-Synch protocol. Treatments included GnRH, GnRH + calf removal, hCG, and hCG + calf removal. Pregnancy rates were higher (P<.05) for GnRH treated cows (48%) compared to hCG treated cows (34%) regardless of calf removal. Calf removal had no effect (P>.1) on pregnancy rates. Cows that received hCG had a higher (P<.05) incidence of short cycles following timed AI and a higher incidence of persistent corpora lutea at the time of insemination. We conclude that hCG is not a suitable replacement for GnRH with the CO-Synch protocol.

Last Modified: 10/21/2014
Footer Content Back to Top of Page