How to evaluate your herd’s reproductive plan.

Taking time to review the reproductive plan can be easily overlooked in the grind of daily chores. However, regular evaluation of the reproductive plan provides necessary context for interpretation of measures evaluated more frequently. A plan evaluation provides some insurance against inadvertent changes due to employee protocol drift or herd management software setup.

Your reproductive plan evaluation can be divided into three sections:

• plan definition;

• herd management software setup;

• protocol validation.

Plan definition 
    

Defining your plan is obviously important—it should be uniquely yours based on what’s right for your cows and your farm goals.

This task can seem overwhelming with many tools available to manage estrus detection and ovulation synchronization. Therefore, involving your entire farm reproductive management team allows for immediate feedback on parts of the plan that work well, and challenges encountered with the current protocol for the individuals tasked with executing it. Taking a teamwork approach to plan development should account for farm labor availability, staff training, and available technology—optimizing them to achieve farm goals.

Some protocols may not have the same success rate on every farm (Borchardt, 2017). The best protocol for a farm is the one that can be delivered consistently and reliably.

The voluntary waiting periods (VWPs) should be clearly defined for all lactation groups. Several studies have demonstrated that there are multiple VWPs that can provide successful conception rates (van Knegsel, 2022).

When evaluating 283 farms in the mySYNCH database—a reproductive management tool from Parnell—farms with a conception rate ranking in the top 10% did not have significantly different VWPs compared to farms outside of the top 10%. This suggests that success depends on many other things than the VWP and should therefore be optimized to fit your farm’s reproductive goals.

If activity monitors are available, the plan should define when and how they are used to help manage reproduction. Regardless of estrus detection method, clearly establish how synchronization (“synch”) is used for cows that were not detected in heat or did not settle to earlier breedings. The basic format of a synchronization program includes presynch, synch for timed artificial insemination (TAI), and resynch of open cows. Some farms opt to breed cows to estrus during the presynch period while others breed 100% to TAI.

Common Synchronization Protocols shows several of the most common protocols entered into the mySYNCH database.

Common Protocols Logistics summarizes which days of the week shots are given and other logistics. To simplify the comparison, all standardized protocols begin on Monday.

However, protocols should begin on the most convenient weekday for the logistics of your farm.
   

The improvement of dairy cow fertility through estrus synchronization began in 1995, with the development of Ovsynch (Pursley, 1995). Although Ovsynch alone did not increase conception rates compared to breeding based on detected estrus, it did allow insemination of cows where estrus was never detected, increasing the overall insemination rate.

A summary of 37 studies found that nearly a quarter of cows are still anovular by 60-70 days post-partum (Beede, 2017). Without synchronization protocols in place, anovular cows are not bred and there is one thing we know for sure: cows that are not inseminated cannot get pregnant.

Drs. Pursley and Wiltbank discovered early on that cows had higher conception rates when the first gonadotropin releasing hormone (GnRH) injection of Ovsynch was given between the fifth and ninth day of the estrous cycle (Vasconcelos, 1999). This led to the development of numerous presynchronization protocols that improved conception rates to TAI.

Resynchronization protocols that begin with GnRH can even be started prior to pregnancy diagnosis to save time. To many dairy producers, giving potentially pregnant cows an injection of GnRH is worth the cost of getting open cows bred one week earlier.

Protocol validation

  
Finally, it is necessary to periodically confirm that the protocol setup in your herd management system is a match to your plan protocol. If your protocol does not match a scientifically-proven protocol and you still achieve exceptionally good reproductive rates, then carry on.
However, if reproductive rates are less than ideal, you may be missing an opportunity to improve reproductive efficiency and efficacy.

REFERENCES

1. Albaaj, A., Durocher, J., LeBlanc, S. J., & Dufour, S. (2022). Meta-analysis of the incidence of pregnancy losses in dairy cows at different stages to 90 days of gestation. JDS Communications, 4(2), 144–148.
2. Beede, D.K., & Washburn, S.P. (2017) Large dairy herd management (3rd ed). American Dairy Science Association.
3. Borchardt, S., Haimerl, P., Pohl, A., & Heuwieser, W. (2017). Evaluation of prostaglandin F2α versus prostaglandin F2α plus gonadotropin-releasing hormone as Presynch methods preceding an Ovsynch in lactating dairy cows: A meta-analysis. J Dairy Sci, 100(5), 4065–4077.
4. Pursley, J. R., Mee, M. O., & Wiltbank, M. C. (1995). Synchronization of ovulation in dairy cows using PGF2alpha and GnRH. Therio, 44(7), 915–923.
5. van Knegsel, A. T. M., Burgers, E. E. A., Ma, J., Goselink, R. M. A., & Kok, A. (2022). Extending lactation length: consequences for cow, calf, and farmer. J An Sci, 100(10).
6. Vasconcelos, J. L., Silcox, R. W., Rosa, G. J., Pursley, J. R., & Wiltbank, M. C. (1999). Synchronization rate, size of the ovulatory follicle, and pregnancy rate after synchronization of ovulation beginning on different days of the estrous cycle in lactating dairy cows. Therio, 52(6), 1067–1078.