5 Ways to Plan For Your Reproductive Synchronization Program

Dr. Erika Nagorske

Jun 27, 2022

Planning ahead for your reproductive synchronization program will have many benefits and will help you successfully take advantage of your calving window. 

Watch Dr. Erika Nagorske, a practicing veterinarian with Southwest Veterinary Services, FBN®’s official veterinary partner, as she discusses the 5 ways to plan for your reproductive synchronization program.

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1. Repro 101

Producers should understand the basics of the cattle reproductive cycle. There are 4 different phases of the cattle estrous cycle which will eventually lead to ovulation. The different waves of the estrous cycle are:

  • Recruitment follicles

  • Selected follicles

  • Dominant follicles

  • Atretic follicles

The entire cycle can take anywhere from 18 to 22 days and in some cases slightly longer. Cattle can respond to drugs differently depending on the wave that they’re going through. In general, it’s good to understand this cycle so you’re able to monitor your cattle throughout the different waves. 


Let’s look at some of the different drugs you may be using throughout the estrous cycle.


These lyse the corpus luteum and start a new follicular wave leading to a new ovulation.

Examples of prostaglandins include:


These stimulate follicle growth leading to new follicular waves.

Examples of GnRH include:


This is a progesterone infused cattle insert. Read more to learn how a CIDR® works

Melengestrol acetate

This is a feed progesterone product that suppresses heat. If you stop giving the animal this product, the cattle will start cycling again. 

2. Goals

It’s good to set goals for your synchronization program. You’ll need to factor in several things when setting these goals. Keep in mind that not every single cow/heifer will conceive. You’ll want to consider AI versus bull breeding. The most common goal for producers is decreasing the actual calving window in order to tighten up your breeding season.

Think about the different methods you’d like to use. This could include giving the animal shots, shots + CIDR®, or feed additives.

Cost is another major factor to consider for your program. Every synchronization program has different costs. Depending on the program you’re using, your cost could vary anywhere from $3/cow to $30/cow. 

Choosing the right program may depend on the type of facilities and labor you have available on your operation. Do you have the time and the people to run your cattle through a chute multiple times? 

3. Advantages of a synchronization program

The biggest advantage is shortening the breeding season. This optimizes both time and labor and gives you a more concentrated calving window. 

It also produces a more uniform calf crop which is more marketable. Heifer development will also benefit from this if you’re going to retain your heifers. There is potential for improved genetics through artificial insemination.

You’ll also be able to more uniformly manage your cows and calves from vaccination for scour shots to nutrition and more. 

4. Requirements for success

Your program needs to be well planned and implemented correctly. Ideally, try to start thinking about your program ahead of calving season. 

Plan to set up an adequate nutrition program for cows, heifers and bulls. You should also ensure that semen handling and storage is done properly by experienced inseminators if you are considering AI. 

Think about how much labor you’ll need around the synchronization process and the facilities you’ll require. 

If you’re using bulls and not using AI, you need to be sure your bull power is adequate. Depending on a bull’s age, this usually means about 10-25 cows/bull. The younger they are, the less cows they’ll be able to cover. Don’t forget to do your Breeding Soundness Exam (BSE) at least four weeks prior to breeding. You may need to retest a bull two weeks later so this will give you plenty of time to be sure the bull is fertile. 

Heat detection

Standing heat occurs when a cow stands still allowing others to mount her. The cow will be in standing heat for about 10 hours. Typically, the rule is to follow the AM/PM rule meaning you will breed your cattle 12 hours after visual standing heat. So if you see this in the morning, you should breed your cow in the evening.

It does take labor to heat detect if you don’t have any bulls naturally covering your cows. You need to have enough time and people to go and watch your cattle. Two to three times a day is minimal for heat watch. Considering that standing heat is a 10 hour window, you need to know exactly when the cow started her heat. 

If you heat detect less, you could miss a standing heat or not know when it started. 

Management of heifers

Breed heifers so they calve 30 to 45 days before your cows. This gives them extra time to breed back for the next year. These are the only animals in your herd that are still growing, while lactating and trying to get pregnant a second time. They will need some grace period. 

5. Protocols

There are many types of protocols to consider. Every program is different and varies in total length, products used, and cost. When it comes to cost, keep these factors top of mind:

  • Hormones

  • CIDR® 

  • Labor

  • Facilities 

  • AI (including storage, straws, technician costs)

Heat detection only

Breed 12 hours after the visual of standing heat.

Heat detection with timed AI

Breeding 12 hours after the visual of standing heat OR at a timed AI window.

Fixed time AI

Breeding at a specific timed AI window without heat detection.

There are many different ways to synchronize your herd. Work closely with your veterinarian to decide which protocol and system will work best for your operation.

  1. https://www.iowabeefcenter.org/bch/EstrusSynchBeef.pdf

  2. https://www.partners-in-reproduction.com/estrus-cycle

  3. https://www.selectsires.com/docs/default-source/resources/heatdetectionandtimingofai_web.pdf?sfvrsn=73f7f1c8_2

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Dr. Erika Nagorske

Jun 27, 2022

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