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Estrous synchronization 911

Sarah Thorson for Progressive Cattle Published on 28 April 2021

It’s that time of year when my phone starts to ring and callers on the other end are desperate for me to triage their estrous synchronization dilemmas.

From giving gonadotrophin-releasing hormone (GnRH) when prostaglandin should have been given, to heifers not cycling after controlled internal drug release inserts (CIDRs) are removed, to an impending snowstorm on the day timed A.I. is scheduled for, I’ve heard many tales of woe. Unfortunately for the caller, I’m often unable to offer much more than a sympathetic ear. To help spare you one of these phone calls, let me offer my top tips for increasing your chances of success on your next synchronization project.

Choose the right synchronization protocol for your operation

The first step toward a successful synchronization program is to choose a protocol that aligns with your goals, your access to time and labor, your facilities and your expectations for results. While research suggests some protocols perform better than others, just because research says it’s the best protocol doesn’t necessarily make it the best protocol for your operation. When choosing a protocol, ask yourself questions such as:

  • How many times am I willing to put females through the chute?
  • How much am I willing to spend on synchronization drugs?
  • Is there anything on the calendar that would prevent me from being able to perform each step of the protocol on the right day and time?

Once you know the answers, you can analyze which synchronization protocol is the best fit for your operation. The best protocol is the one you are 100% confident you can perform perfectly from start to finish.

Have the right people in place to make your protocol a success

The people who you have helping administer your synchronization protocol can have a huge impact on whether it is ultimately successful or not. Everyone on your crew should understand the protocol and the importance of each step. From why the timing of each step is critical, to proper dosage and administration of the synchronization drugs – education is key.

Also important to your success is proper cattle handling. Most synchronization protocols require three to four trips through the chute. When it comes to gathering, sorting and moving cattle through the A.I. barn, your goal should be to induce as little stress as possible.

If choosing a heat-detection protocol, accurate and thorough heat detection is key

If you choose a protocol that involves heat detection, your success is tied directly to how good your heat detection is. To achieve the best heat detection results, heat detection should be performed a minimum of twice per day for at least 30 minutes. Research tells us that most mounting activity associated with heat occurs during the overnight hours (7 p.m. to 7 a.m.). Therefore, heat detection should be performed early in the morning and late in the evening to increase your chances of detecting the most females in heat.

Finally, if heat detection is going to be a part of your synchronization protocol, it’s a good idea to consider using a heat-detection aid. A good heat-detection aid can be your eyes when you can’t be there and decreases the odds you miss identifying females in heat.

Ensure that females to be synchronized are good candidates for A.I.

No matter how closely you follow protocol, if the females you are synchronizing are not good candidates for A.I., then it is likely you will not achieve the results you desire. Here are a few rules of thumb to follow when selecting females for A.I.

Criteria for synchronizing heifers:

  • Should have achieved 60% to 65% mature bodyweight
  • Minimum of 50% should have a reproductive tract score of 4 or greater at six weeks before breeding

If you don’t have a veterinarian in your area who offers reproductive tract scoring, don’t panic. You can achieve the same thing by visually observing heifers for heat in the weeks and months leading up to breeding. You want to observe at least 50% cycling six weeks prior to breeding.

Criteria for synchronizing cows:

  • Body condition score of 5 or greater at calving
  • Group should average a postpartum interval of 40 days or more at the beginning of the protocol
  • Each cow should be a minimum of 21-days postpartum at the time of Eazi-Breed CIDR insertion
  • Low incidence of calving difficulty

Selecting a protocol that aligns with your goals, good compliance to that protocol, surrounding yourself with the right team and paying attention to details can help you avoid having to make an estrous-synchronization 911 call this breeding season.  end mark

ILLUSTRATION: Illustration by Corey Lewis.

Sarah Thorson
  • Sarah Thorson

  • U.S. Beef Marketing and Education Manager
  • Genex
  • Email Sarah Thorson

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