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Angus Journal
Copyright © 2015
Angus Journal

Protocols and Planners
for Estrous Synchronization

by Barb Baylor Anderson for Angus Productions Inc.

NASHVILLE, TENN. (Aug. 5, 2010) — Whether you are new to the processes of estrous synchronization or a veteran, having a plan for utilizing protocols can go a long way in helping you manage for profitable success. Justin Rhinehart, University of Tennessee beef specialist, addressed opportunities during the Applied Reproductive Strategies in Beef Cattle (ARSBC) Conference in Nashville, Tenn.

Justin Rhinehart

Justin Rhinehart

“While many options exist for synchronization of estrus and ovulation, the Beef Cattle Reproduction Leadership Team has developed a short list of protocols that each producer should evaluate according to their available resources and the cows or heifers intended for synchronization,” he said. “Considerations should include time and skill available for heat detection, body condition, days postpartum in cows, facilities, experience and cost.”

Begin by determining how much, if any, heat detection is feasible or desired, Rhinehart said. The recommended protocols should be divided into three groups based on the amount of heat detection required — heat detection for seven to eight days, heat detection for three days followed by fixed-time AI of all remaining animals, and strict fixed-time AI.

“Any synchronization protocols are recommended for mature cows with a body condition score (BCS) of 5 or greater that are 50 days or more since calving at time of AI. If a high percentage is not in that category, consider protocols with a progestin, such as a CIDR,” he advised. “Progestin will induce some non-cycling cows to cycle and improve their chance of conceiving to AI.”

Heifers should attain 60% of their mature weight prior to breeding. Rhinehart said producers that score heifer reproductive tracts 50-60 days prior to breeding have a true measure of physiological maturity and time to adjust rations prior to breeding. If half have a tract score of 3 or greater at that time, estrous synchronization programs may be more successful.

“Length of protocol, number of times handled, and the ability to successfully deliver treatments such as MGA are other factors that must be considered when choosing a synchronization protocol,” he added. “Management system, feed resource flexibility, and facilities will also play a role in which protocol works best in each particular environment.”

He further recommended producers maintain Beef Quality Assurance (BQA) compliance, use the correct pharmaceuticals on the correct day, stay on label and use data-based protocols. He advised having a backup plan for technicians, semen, pharmaceuticals and other labor.

Rhinehart said resources are available to help producers with estrous synchronization. One of the first tools to become available was developed by specialists at the Iowa Beef Center (IBC). Click here to access the spreadsheet-based planning tool, which allows users to answer questions regarding desired breeding/calving date, type of females being subjected to the protocol, synchronization system and cost of materials and labor. Based on the inputs, the software creates a printable calendar with important dates and times for injections and insemination and generates a detailed economic analysis.

Similarly, Mississippi State University Extension has a spreadsheet with a planning calendar for injection, breeding and calving days. Click here to access. Extension has also developed an estrous synchronization smartphone application based on the spreadsheet, which may help facilitate reproductive management decisions in the field.

Editor's Note: This article was written under contract or by staff of Angus Productions Inc. (API), which claims copyright to this article. It may not be published or redistributed without the express permission of API, publisher of the Angus Journal, Angus Beef Bulletin, Angus e-List and Angus Beef Bulletin EXTRA. To request reprint permission and guidelines, contact Shauna Rose Hermel, editor, at 816-383-5270.