Kansas Agricultural Experiment Station Research Reports

Article Title

Long-term CIDR program for synchronization of estrus in beef heifers produces acceptable AI pregnancy rates

Authors

Sandra K. Johnson
J.W. Bolte
John R. Jaeger

Keywords

Cattlemen's Day, 2010; Kansas Agricultural Experiment Station contribution; no. 10-170-S; Report of progress (Kansas State University. Agricultural Experiment Station and Cooperative Extension Service); 1029; Beef Cattle Research, 2010 is known as Cattlemen's Day, 2010; Beef; CIDR; Estrus; Heifers; AI; Pregnancy rates

Abstract

Routinely achieving pregnancy rates greater than 50% with fixed-time artificial insemination (AI) in heifers has been difficult. The Beef Reproduction Task Force recently added the intravaginal progesterone-releasing device (CIDR)-Select to its list of recommended fixed-time AI protocols. Research and field trials in Missouri have achieved AI pregnancy rates in the range of 55% to 60%. Another relatively new protocol is the 5-day CO-Synch, a timed AI protocol + CIDR that has produced pregnancy rates similar to or higher than those obtained with the standard 7-day CO-Synch + CIDR protocol. It is not known whether these two systems differ in terms of estrous response. The objective of the current study was to compare effects of a long-term, 14-day CIDR-Select protocol and a 5-day CO-Synch + CIDR protocol on estrous distribution and AI pregnancy rate in yearling beef heifers.

Recommended Citation

Johnson, Sandra K.; Bolte, J.W.; and Jaeger, John R. (2010) "Long-term CIDR program for synchronization of estrus in beef heifers produces acceptable AI pregnancy rates," Kansas Agricultural Experiment Station Research Reports: Vol. 0: Iss. 1. https://doi.org/10.4148/2378-5977.2881