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Think carefully before investing in automated heat detection

John Lee Published on 09 February 2012

Over the years, science has delivered reproduction management technologies that have helped dairy producers become more efficient and productive. Timed artificial insemination (TAI) is one practice that greatly improves reproductive performance on dairies.

Recently, automated heat detection systems are showing promising benefits in some herds as well. You might even be wondering if this new technology can improve your dairy’s breeding performance.



Much like other reproductive programs, the usefulness of automated heat detection depends on the individual dairy’s management system, heat detection capabilities and breeding goals.

Get cows serviced
A successful reproductive program depends on inseminating cows for the first time as soon as possible after the end of the herd’s voluntary waiting period.

Every cow has what’s known as an “allowable breeding space.” This is the length of time in which it is economically viable to continue trying to get that individual cow pregnant.

The number of days to first service is the biggest driver of how many potential breeding opportunities a cow will have within the allowable breeding space.

Synchronization programs, including pre-synchronization for first service, benefit all herds – including those with automated heat detection systems – by ensuring all cows are inseminated shortly after the end of the voluntary waiting period, with a high likelihood of a successful outcome.


Pharmaceuticals used in synchronization programs address many ovarian and uterine health problems. This includes cows which are anovular, anestrous, have a pyometra or are not actively expressing heat.

Once cows are bred for the first time, the next-most important aspect of successful reproductive management is to quickly identify open females and re-breed them. Accurate heat detection will decrease the interval to next insemination for these cows.

However, a percentage of open cows will not be identified by heat detection. These are the cows found open at pregnancy check.

Enrolling these cows in synchronization programs helps ensure these open cows are reinseminated in a timely manner and reduces the interval between breedings for those failing to conceive but not expressing heats well.

Using a resynchronization program, producers can guarantee all cows will be reinseminated within 11 days of an open vet check diagnosis. This is powerful because cows diagnosed open have already been missed in heat once, otherwise they would not have been up for pregnancy check.

Cows must show heat
Producers considering automated heat detection should be aware that this tool will only identify cows with normal heat activity. Every dairy has a population of cows that do not show heat for a number of reasons.


Some have uterine health problems or will not cycle properly due to ovarian problems. These cows also can be in silent heat or have an illness or lameness that prevents them from showing heat. Even healthy cows can vary in the duration and intensity of estrus.

It is not unusual for more than 20 percent of the cows in a herd to not express heat well enough for detection by any method, including an activity-based monitoring system. Synchronization programs help ensure cows not detected in heat by any method are inseminated in a timely manner.

Consider carefully
If you are considering adopting an automated heat detection system, be prepared to make changes in your herd’s breeding routines as well as a significant upfront capital investment in equipment.

Automated heat detection systems are designed to identify cows displaying active estrus expression. If your herd is struggling with low heat detection rates, investing in an automated heat detection system may help improve heat detection intensity and identify more cows for insemination.

But operations with already high heat detection rates may not see a favorable return on the investment.

Successful timed-A.I. programs effectively eliminate the variability in estrus detection and make efficient use of the allowable breeding space.

Automated heat detection may work in tandem with synchronization to improve insemination efficiency and help make better use of the allowable breeding space for some dairies.

However, dairies with high pregnancy rates should carefully consider a decision to change any aspect of their breeding program.

If your current breeding program achieves a pregnancy rate in the 20s or higher, meddling with your system could result in no change or, worse, a decrease in performance rather than the improvement you expect.

Before making any changes, it is important you take time to review your breeding program with your veterinarian. No system is “one size fits all,” and your veterinarian can provide key insights before you make a large investment or changes.

Make sure that whatever program you are implementing on your dairy provides your cows their best chance of timely pregnancy.  PD

Things to consider ...
Automated heat detection technology can be a tool to improve reproductive performance. But it isn’t for everyone. If you’re considering the investment, make sure to conduct a comprehensive evaluation that includes the cost of equipment and time it will take to break even.

That time to break even should include a “sensitivity analysis,” which looks at different outcomes – optimum results, median range results and “worse case” (minimal repro improvements) after a significant investment.

Here are a few other questions to ask yourself:

1. What is the current herd pregnancy rate with my current program?

2. What is the current heat detection rate with my current program?

3. What do I think will improve with an automated heat detection system?

4. Will the automated heat detection enhance my current system?

5. What are the risks with implementing this with my current system or using this to replace my current system?

6. Is the cost worth it?

John Lee

Senior Veterinarian
Pfizer Animal Health