Fertility: The New Normal

By Kim Egan, DVM, Director of Strategic Accounts, GENEX

The world of dairy is one of continuous improvement. Tight margins, expense of heifer rearing, and the drive to improve herd genetic potential have made excellent reproduction an even more important item on many farms. Over the last several years, much has been learned and implemented to improve cow comfort, nutrition, and health. Genetics, fertility-enhancing synchronization programs and market pressures have all had an impact as well. An article written in 2015 regarding reproductive goals is already out-of-date. Below are the top five items being tracked on dairies today and updated goals for reproductive performance given the advancements over the last few years.

1) Percent pregnant by 150 Days in Milk (DIM). It seems many of the herds we work with have exceeded the goal of 75% that we were looking at a few years ago. Confirming this, our Dairy Performance Navigator system shows the top 10% of herds by milk production out of 280 Holstein herds, each with over 500 cows, now average 81% of the herd pregnant by 150 DIM. GENEX Excellence in Reproduction Award winners for 2017 averaged 88% pregnant by 150 DIM. A new goal of >80% of cows pregnant by 150 DIM seems appropriate now.

2) 3-week pregnancy rate. Depending on the program your farm uses, the calculation of cows that are eligible to be bred may vary. Ultimately, the pregnancy rate is driven by conception rates and service rates. Factors that diminish estrus expression or detection or reduce conception will reduce the pregnancy rate. Many factors that affect reproductive success are shown below.

Holstein herds with 500 cows or more in our Dairy Performance Navigator℠ (DPN℠) program average 25% annual pregnancy rates, with the top 10% by cow pregnancy rate achieving an average of 34%. A good goal for 3-week pregnancy rate is now 30%.

3) Conception by breeding code, service number, semen type. Many herds are using sex-sorted semen in the lactating herd as well as their heifers, this frequently has lower conception than conventional semen. There are also differences in synchronization programs for first service and later services. It is best to track conception of differing breeding codes (ex: resynchronization versus heat detection) and semen types, so that if change in reproductive performance is desired, the areas can be monitored in relation to the goal and to historical performance. Good goals here would match the following: The top 10% of Holstein herd by cow pregnancy rate in our DPN℠ program are achieving first service conception >45% in their lactating herds. For heifers, the Dairy Calf and Heifer Association gold standard for first service conception rate with sexed semen is 60%.  

4) Percent of heifers pregnant at 15-17 months old. This is still a favorite measure of the overall efficiency of the virgin heifer reproductive program. The range can be adjusted based on your voluntary waiting period, but should allow time for breeding and pregnancy diagnosis. Delays in moving heifers into the breeding pen or inadequate heat detection will reduce this percentage. Skipping the pregnancy examinations or missing data will also skew this data. Increased percentages reflect efficient use of days (or months) heifers are fed before freshening and return income to the dairy. Currently, the top 10% of Holstein herds by heifer pregnancy rate in our DPN℠

program are achieving 85% of heifers pregnant at 15-17 months, that is an excellent goal for any dairy farm.

5) Number of eligible animals beyond first service deadline not inseminated. Many farms are achieving 100% of animals (both cows and heifers) inseminated within 28 days of their voluntary waiting period. It is important to have a fixed goal by which all animals should be inseminated, yours may be different than 28 days or may include weight for the heifers. Animals removed from breeding pens and/or missed on synchronization programs may not be inseminated, reducing the service rate and reducing the dairy’s efficiency. The goal for animals beyond first service deadline not inseminated is zero.