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Top 10 parameters to monitor reproductive performance

Kim Egan Published on 31 December 2015

As the saying goes, you can’t manage what you don’t measure. Dairy producers put a lot of time and effort into reproductive programs, but effectively managing those programs requires performance measuring.

Reproductive measurements and monitoring enable producers to make timely and accurate management decisions for improvement.



The following are today’s most commonly tracked, reviewed and discussed reproductive parameters:

1. Percent of herd pregnant by 150 days in milk (DIM)

If you want to pick one number to focus on, consider this one. It gives an accurate snapshot of the reproductive efficiency of a herd. This parameter is important because production of milk pounds and solids decreases in late lactation.

Therefore, to maximize production efficiency, reproductive programs need to be effective and timely. Factors that can limit the percent of herd pregnant by 150 DIM are numerous but may include poor transitioning from dry to lactating, poor conception, infertility, disease issues, inadequate enrollment for insemination or low estrus detection.

Reproductive award-winning herds have achieved more than 89 percent of cows pregnant by 150 DIM; with good reproduction, 75 percent should be a realistic minimum goal for a dairy.*

2. Number of eligible cows beyond first-service insemination deadline not inseminated

No matter the protocols for insemination, no cows should “fall off the radar.” A cow that does not get bred does not become pregnant. It is important to have a fixed goal for DIM by which all cows should be inseminated – either by estrus detection, a synchronization program or a combination of the two.


Sometimes cows are moved to non-breeding pens due to special needs or are missed for other reasons; monitoring this allows for identification and resolution of these issues. Zero is the goal here.

3. Cows monthly conception by service number and lactation

Monthly monitoring of first service, second service and overall conception for first-lactation versus older cows can reveal potential opportunities for improvement. For example, first-lactation cows with subpar average daily gains as virgin heifers may show decreased early service conception.

In older cows, poor conception to first service may be related to dry period issues. Difficult calvings and maternity issues may result in postpartum health events and lead to decreased early service conception across lactations.

Later-service conception may be affected by feed issues, mastitis, poor compliance on resynchronization or improper estrus detection. Stress from sources such as heat or overcrowding can affect all services.

Annual conception data on more than 120,000 Holsteins in herds with 501 to 2,000 cows show first-lactation cows averaging 47 percent conceiving to first service, 39 percent on second service and 41 percent overall. For older Holstein cows, the average conception is 39 percent on first service, 34 percent on second service and 36 percent overall.*

Annual conception data on more than 14,000 Jerseys in similar-sized herds show first-lactation cows averaging 47 percent conceiving to first service, 41 percent on second service and 42 percent overall. For older cows, the average conception is 44 percent on first service, 40 percent on second service and 41 percent overall.*


4. Cows monthly conception by breeding code

Typical protocols being tracked are for standing heats, first synchronization and resynchronization. Many dairies have other codes listed to help the breeding team determine which programs are getting the best results. For example, herds with activity systems can have estimated time to ovulation broken into different codes.

Compliance and timing are the biggest factors affecting the success of synchronization programs. Cow fertility, semen quality and handling, and timely estrus detection are key factors across all codes.

Modern synchronization protocols can enhance fertility as well as get anovular or cystic cows to cycle, so these programs potentially boost conception. Conception to standing heats is usually a bit lower than with these programs but can result in the same number of cows pregnant by 150 DIM.

What works best? It depends on labor, logistics, etc. If you compare to the monthly cow conception data by service number and lactation, is the conception on any code falling below expectations?

5. Three-week pregnancy risk

This number is arrived at by multiplying the service rate and the conception rate. Therefore, the plethora of factors that affect estrus expression, estrus detection and conception will affect this percentage.

Annual three-week pregnancy risk averages can be quickly compared to 120-day and to the last three weeks that are pregnancy checked to determine how reproduction is trending within a herd.

This percentage represents the effectiveness of the reproductive program for each three-week cycle over time. Be aware that some programs exclude “do not breed” cows, while others include them.

Currently, the top 25 percent of 500- to 2,000-cow Holstein herds by cow pregnancy rate are averaging a 28 percent three-week pregnancy risk, while the top 25 percent by cow pregnancy rate of similar-sized Jersey herds are averaging a 29 percent three-week pregnancy risk.*

6. Percent of heifers bred and percent pregnant at 15 to 17 months old

This is a measure of the overall efficiency of the virgin heifer reproductive program. The range in age allows adequate time for breeding and pregnancy diagnosis. (Some dairies may narrow or lower the age range.)

Factors such as moving heifers into the breeding pen at or after the voluntary waiting period, decreased fertility or inadequate heat detection will reduce these percentages. Delays reduce profitability by increasing the number of days (or months) heifers are fed before they begin to milk and return income.

The top 25 percent of Jersey herds by heifer pregnancy rate average 96 percent heifers bred and 75 percent recorded as pregnant by 15 to 17 months old. The top 25 percent of Holstein herds by heifer pregnancy rate average 97 percent heifers bred and 81 percent recorded as pregnant by 15 to 17 months old.*

7. Virgin heifer monthly conception by service number and semen type

Many producers use at least some sexed semen on early services in their heifers, so determining the conception to first versus later services by semen type is important. The same abundance of factors affects heifer reproduction as it does the adult herd reproduction.

The Dairy Calf and Heifer Association’s Gold Standards II sets a goal of more than 70 percent conception to first service with conventional semen. Expect 7 to 12 percent lower conception with sexed semen. Currently, the top 25 percent of Jersey and Holstein herds by heifer pregnancy rate average 52 percent and 57 percent overall conception, respectively.

8. Percent of heifers fresh at more than 24 months old

This represents the efficiency of the heifer-rearing and breeding programs from nutrition and pen moves to heat detection and conception. Heifers that “slip through the cracks” raise the percentage and reduce profitability.

Herds in the top 25 percent by heifer pregnancy rate average fewer than 15 percent calving after 24 months old, and this number gets a bit lower each year.*

9. Percentage of abortions in heifers and cows

Here, the term abortion refers to any cow or heifer recorded as pregnant who is then determined to be open without a calving event. A certain amount of early embryonic loss is to be expected, and herds with very early pregnancy diagnosis generally have a bit higher abortion rate.

Diseases (such as bovine viral diarrhea) and stress from heat- and feed-related issues (such as mycotoxins) can impact this number significantly.

Annual averages for abortion events in our data set are: Jersey cows, 7 percent; Jersey heifers, 3 percent; Holstein cows, 9 percent; Holstein heifers, 3 percent.*

10. Percent of stillbirths by lactation group

This can be a reflection on maternity practices, personnel, genetics, disease or nutrition. All the resources used to obtain and maintain a pregnancy are for naught if the calf is born dead.

First-lactation heifers in both the Jersey and Holstein data sets average 7 percent stillbirths, while older cows in both breeds average 4 percent stillbirths. Herds with the best results in this area average 2 to 3 percent stillbirths annually.*

Reproduction is affected by an abundance of factors from genetics to weather. Monitoring performance allows timely and accurate management decisions for herd reproductive improvement.  PD

*Source: Current performance levels in both Holstein and Jersey herds from the Genex Dairy Performance Navigator database.

Kim Egan
  • Kim Egan

  • National Account Senior Consultant
  • Genex Cooperative Inc.
  • Email Kim Egan