Are there technologies now, or potentially in the future, that will be more cost-efficient to drive pregnancy rate equivalent to or greater than current synchronization or fertility programs?
This was the topic of discussion at a workshop in which I recently participated. “Is whole-herd synchronization here to stay?” was the title of the session that took place during the International Cow Fertility Conference in Westport, Ireland.
The developer and moderator of the workshop, Dr. Matt Lucy of the University of Missouri, generated discussion on how newer reproductive management technologies might someday replace synchronization programs.
This article will take a look back at how we got to where we are today, along with a look forward at the future of dairy cattle reproductive technologies.
The story of synchronization programs
Synchronization programs trace back to the 1970s when prostaglandin F2-alpha (PGF-2) products dinoprost tromethamine (marketed now as Lutalyse and Prostamate) and cloprostenol sodium (marketed now as Estrumate and EstroPlan) began. PGF-2 synchronization programs were successful in synchronizing estrus in cycling cows in approximately a five-day period.
It wasn’t until the early 1990s that studies were published using PGF-2 and GnRH together to control timing of estrus. Soon after, Ovsynch was developed to synchronize ovulation, not estrus. Ovsynch was unique because it utilized PGF-2 to control corpus luteum (CL) regression and GnRH to control follicle development and ovulation.
Ovsynch reduced the range in time to ovulation after PGF-2 from approximately a five-day period to an eight-hour period in synchronized cows. The key management advantage was that all cows could receive first A.I. at a predetermined time in lactation and a subsequent A.I. shortly following pregnancy diagnosis if not confirmed pregnant.
Over the next decade, scientists utilized Ovsynch as a tool to gain a greater understanding of the physiological limitations of dairy cow fertility and how to control ovarian development to enhance fertility.
Three programs were developed from these studies that increased the chance of pregnancy following standing estrus from approximately 30 percent to 45 percent (G6G, Double Ovsynch and Presynch-10 or 11). We refer to these programs now as “fertility programs.” (Visit the Reproductive Management of Dairy Cattle website for management calendars and videos on how fertility programs work.)
Fertility enhancements from these current programs give producers other advantages with their reproductive management programs. For example, time to first service can be delayed to 80 days to avoid lactations that are too short since all cows will receive first A.I. by that time with expectations of a 45 percent chance for pregnancy.
In addition, both pregnancy losses following first pregnancy diagnosis and twinning are reduced. The chance of multiple ovulations, the primary reason for twins, is reduced in cows that develop ovulatory follicles under greater concentrations of progesterone, a key advantage of fertility programs.
What does the future hold for synchronization programs?
So back to the original question: Where do we go from here? It is clear we can drive pregnancy rate with fertility programs, but the programs are laborious and compliance can be a problem. How do we utilize new findings on improving cow fertility to develop simpler solutions to the problem?
Are there other technologies or genetic strategies in place, published in scientific literature, without “whole-herd synchronization” that would indicate the potential to drive pregnancy rate equivalent to the fertility programs described above?
Synchronization and accelerometers
Accelerometers are being marketed to enhance the accuracy of estrus detection. These systems have the potential to enhance pregnancy rate on farms that prefer not to use fertility programs. In addition, there are other measurements that can enhance general management of cows such as measuring rumination.
Most herds utilizing this technology are small-sized to medium-sized farms. For farms that want to strictly inseminate following a detected estrus, there is no downside. Producers only using estrus detection should expect an increase in pregnancy rate from the increase in estrus detection rate.
But can just relying on only estrus detection drive pregnancy rate to that of fertility programs? The answer is “no” for two key reasons:
1. The chance of a pregnancy following A.I. is 40 percent less in multiparous cows inseminated following a detected estrus compared to cows on fertility programs. Accelerometer systems cannot change the key physiological characteristics in cows that cause low fertility.
2. Accelerometer systems cannot provide a way to inseminate anovular cows (not yet cycling following calving). Most data would suggest that at 60 days in milk (DIM), 15 to 25 percent of cows in the breeding group have not yet ovulated and started a new estrous cycle.
Fertility programs not only give anovular cows a chance to conceive, but they will also induce cyclicity in most cows. Also, accelerometers cannot reduce twinning or pregnancy losses.
The key strategy for producers utilizing accelerometers is to combine this technology with fertility programs. There are a number of strategies that can be developed that minimize or maximize the use of synchronization programs with accelerometers.
One example of a minimal strategy would be to set a DIM that cows will receive first timed A.I. utilizing Ovsynch if not detected by the accelerometer. This would ensure all cows receive an insemination at a reasonable DIM. Accelerometers can, of course, be utilized to detect cows that may return to estrus after first A.I.
Then, cows subsequently diagnosed not-pregnant should again receive Ovsynch at some reasonable amount of time following diagnosis to see that DIM are not overextended. Given this strategy, pregnancy rates will clearly improve compared to only relying on A.I. following a detected estrus.
A more aggressive approach would be to utilize Presynch-14/Ovsynch with accelerometers and estrus detection (i.e., cherry pick) following both PGF-2 injections and timed A.I. the remainder. Then, utilize the approach above for re-insemination following a not-pregnant diagnosis.
The most aggressive approach would be to utilize only a fertility program for first A.I., accelerometers for detection of cows returning to estrus and a combination of an aggressive re-synch program and accelerometers for A.I. after a not-pregnant diagnosis.
This would clearly be the gold standard for achieving the greatest pregnancy rate possible. But, of course, it is a very expensive approach and could be referred to as the “holy cow” approach.
How about genetics? Several key groups of dairy scientists in the U.S. and internationally are gaining a greater understanding of the genomic aspects of dairy cattle fertility. Integrating new genomic technologies into the nation’s dairy herd will likely improve levels of fertility in our dairy cows in the future.
So is whole-herd synchronization here to stay? For now, at least, it appears using fertility programs to overcome impaired physiological parameters of our dairy cows is the only way to maximize the chance of a pregnancy following A.I.
For a more detailed explanation of the history of Ovsynch and a review of the data behind fertility programs, read “The cow as an induced ovulator: Timed A.I. after synchronization of ovulation” by Milo Wiltbank and Richard Pursley. This can be found under “Recent Publications” on the Reproductive Management of Dairy Cattle website . PD
Dr. J. Richard Pursley is co-creator of the Ovsynch program. His current program focuses on enhancing fertility of dairy cattle.
References omitted due to space but are available upon request. Click here to email an editor.
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J. Richard Pursley
- Professor- Department of Animal Science
- Michigan State University
- Email J. Richard Pursley
