Thesis Title

Comparison of CIDR and Estrumate as Estrus Synchronization Methods


Chad Duit

Date of Graduation

Summer 2001


Master of Natural and Applied Science in Agriculture


College of Agriculture

Committee Chair

Thomas Perkins

Subject Categories



Reproductive efficiency is probably the single most important factor regarding the profitability of the beef cattle industry. Manipulation of the estrous cycle is one way to enhance beef cattle production. In this experiment, a progestogen (CIDR-B® device, controlled internal drug release) and a prostaglandin (Estrumate®) were used as synchronization devices to see which resulted in tighter synchronization of estrus and higher conception rates. A non-synchronized group was also observed for estrus and subsequent conception as a control. Mature cows and virgin heifers used in the study ranged from 3-5 years in age and 16-26 months of age, respectively. Thirday days prior to the start of the experiment all cattle were examined via rectal ultrasound to insure all cattle were cycling normally and none were currently pregnant. Cattle were then randomly placed into one of three treatment groups: 1) CIDR®, 2)Estrumate®, 3) Control. Group 1 was treated with a single CIDR® intravaginal device on Day 0 and removed on Day 11. Group 2 was treated on Day 11 with 2cc of prostaglandin administered intramuscularly. All cattle had a commercial heat detection device placed on their tailhead on Day 11 to aid in heat detection. Daily observations of the cattle began Day 12 of the experimentl. Cattle were checked twice daily (dayn and dusk) for standing heat or estrus. Females were artificially inseminated (AI) 12 h after observed standing heat. On Day 32 a clean up bull was placed with herd to breed any females that failed to conceive via AI. Meana time to onset of estrus was significantly different (p < .05) in the CIDR® group (62.4h) and the prostaglandin group (67.2h) as compared to the Control group (206.4h). Prostaglandin and control groups each exhibited estrus in 86% of the animals; whereas in the CIDR® group only 83% exhibited estrus; however, no significant difference was shown. More cattle in the CIDR® group (67%) conceived via AI; 57% of prostaglandin and control animals conceived by AI. Prostaglandin showed the highest percent (100%) of total percent conceived through AI and natural service by the bull. Control group animals had an 86% total conception rate and CIDR® followed with 67%. CIDRs® do not show acceptable percentages on total conception rates when compared to the prostaglandin (100%) and Control (86%) groups. However, both CIDRs® and prostaglandins are adequate estrus synchronization methods.


© Chad Duit