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ADSA hears synchronization, superovulation research

Glaucio Lopes Published on 30 August 2013

The popular reproduction management strategies discussed during the 2013 American Dairy Science Association (ADSA) Joint Annual Meeting in July revolved around new variations on synchronization protocols and a new drug for superovulation.

As for new reproductive technology research, there was almost nothing new presented to support the use of accelerometers to manage reproduction on the farm level.

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The lack of new research doesn’t equal a lack of interest in the newest estrous-detection technology.

In fact, researchers have been even more inspired to work closely with accelerometers, not only because of their unique estrous-detection abilities for farmers but also the newly added features like rumination and feed monitoring.

Researchers are interested in monitoring the activity of the animal for heat detection, but they are also interested in the rumination data that will allow them to access animal health and fresh and transition cows’ performance.

I foresee more new relevant data will be presented during the next year or two, which will further clarify how the incorporation of these systems can help dairies’ management in general.

The use of synchronization programs to manage reproduction on dairy farms remains strong. Researchers continually work hard to find new strategies for the Ovsynch protocol; they are creating ways to increase conception rates while still considering weekly events that occur on-farm.

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An epidemiologic study from 2008 to 2012, with a total of 1,142,821 breeding records from 40 states, presented an estimation of the use of synchronization programs in U.S. dairy herds.

It was shown that across these dairies, 29.9 percent of the artificial inseminations (A.I.) were performed following a synchronization program, and the use of this strategy grew around 5 percent in the last five years.

There was no difference in conception results between synchronized cows (32.6 percent) and cows receiving A.I. to estrous (33.4 percent).

Another study showed the impact use of timed A.I. (TAI) on reproductive performance and culling rate in Wisconsin dairy herds.

Herds were divided into quartiles of TAI use intensity, with the first quartile (Q1) including farms with least use of TAI and the fourth quartile (Q4) including farms with most use of TAI (i.e., Q1: 0 to 36 percent of TAI used, Q2: 37 to 55 percent, Q3: 56 to 69 percent and Q4: 67 to 99 percent).

Across herds, TAI accounted for an average of 52 percent of all services.

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As the proportion of breeding following a TAI protocol increases, the proportion of herds with service rate more than 50 percent, conception rate more than 35 percent, and 21-day pregnancy rate more than 18 percent also increased, demonstrating that farms that use more TAI are much more likely to have better reproductive efficiency.

Also there was a correlation of herds with high 21-day pregnancy rates having high cull rates that are mostly not related to reproductive issues.

A new technique to presynchronize cows at first service was also presented at the ADSA conference.

Farms using the Ovsynch protocol and its variations for first service after calving usually presynchronize cows with a sequence of injections to get better synchrony to the protocol and achieve higher conception (or pregnancies per A.I.) results.

Presynch-Ovsynch, Double-Ovsynch and G6G are among those strategies that can be used, and injections are usually given in different days of the week.

A study showed that cows presynchronized with prostaglandin (PGF2α) and gonadotropin-releasing hormone (GnRH) on the same day, seven days before the Ovsynch protocol, had similar pregnancies per A.I. than cows presynchronized with Presynch-10/Ovsynch [Presynch-10 consists of two prostaglandin (PGF2α) injections 14 days apart, 10 days before the initiation of the Ovsynch protocol].

In this study, with 444 cows receiving first A.I. between 75 and 81 days in milk, both strategies had 45 percent pregnancies per A.I.

It’s important to note that all cows received an extra injection of PGF2α during the Ovsynch protocol 24 hours after the regular injection to enhance luteolysis and obtain better synchrony to the protocol.

A new drug for superovulation excited those interested in embryo transfer.

One study compared the use of a single injection of a long-acting recombinant bovine FSH (follicle-stimulating hormone – B-rbFSH) with the standard 300 mg of porcine pituitary-derived FSH (pFSH), usually administered in eight decreasing doses over a four-day period, on superovulatory response (number of ovulatory follicles and corpora lutea – by ultrasound) and embryo recovery seven days after A.I., using nonsurgical flushing procedure, in non-lactating virgin heifers.

Heifers had their ovulation induced with 2,500 IU of hCG (human chorionic gonadotropin) at the end of the protocol and received A.I. 12 and 24 hours after hCG treatment.

Number of heifers superovulated, number of follicles, CL and quantity of good-quality embryos were not different between the single injection of 50 μg of B-rbFSH and the standard four-day injections of 300 mg of pFSH.

At the practical recovery structures standpoint, a study showed it is possible to improve embryo recovery rate from superovulated Holstein dairy cows re-flushed 30 minutes after the initial embryo-recovery flush. One hundred and fifty-six flushings from 49 cows were evaluated.

Cows had the two-way catheter placed in each horn individually, and one liter of flush media was used per horn. After the initial uterine horn flush, the catheter was displaced back to the cervix, and flush media was placed in the uterus.

After 30 minutes, cows had their entire uterus re-flushed with one liter of flush media. A total of 8.4 structures were recovered during initial flushing versus 9.9 after flush and re-flush, demonstrating an increase on the average yield of structures by 17.9 percent (1.5 structures).

Using this technique resulted in increased number of structures, which could be of value on the recovering embryos of high genetic and commercial value.

Overall, the ADSA Joint Annual Meeting presented a wonderful amount of research and knowledge to attendees, which in turn can assist farmers with the successful management and care of their herd. PD

References omitted due to space but are available upon request. Click here to email an editor.

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Glaucio Lopes
Reproduction Specialist
Accelerated Genetics

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