Newsletter – 2020 – April

President's message

From the DCRC President’s Desk
By Julio Giordano

Given these uncertain times due to the worldwide COVID-19 pandemic, I hope that you and your family, friends and colleagues are doing well. I’m grateful for farmers – and those who serve farmers – for being the backbone of the world’s food, fiber and fuel supply. During these trying times, I find strength and hope in medical experts and advanced technologies that will help us overcome this deadly virus.

Let’s move on to some rosier topics. April is a big month for Dairy Cattle Reproduction Council (DCRC).

Herd repro nominations due April 30

Nominations for DCRC’s Herd Reproduction Awards program are open through April 30. This program honors outstanding dairy operations for reproductive efficiency and well-implemented management procedures. An anonymous panel of judges evaluates key metrics, including voluntary waiting period, interbreeding intervals, heat detection, conception rate, pregnancy rate, value of reproduction and culling rate. Reproduction numbers are based on the 12-month period Jan. 1, 2019-Dec. 31, 2019.

Professionals who serve the dairy industry, such as veterinarians, extension agents, artificial insemination and pharmaceutical company representatives, dairy processor field staff and consultants, nominate dairy operations for this contest. For more information about the Herd Reproduction Awards program or to nominate a herd online, click here. Direct questions to: JoDee Sattler at: jodee@dcrcouncil.org.

Apply for DCRC Scholars program

Also, DCRC Scholars applications are due April 30. Now in its second year, the DCRC Scholars program recognizes an outstanding graduate student who is studying some aspect of dairy cattle reproduction. The winner receives a travel scholarship (airfare, hotel, meeting registration and meal stipend) to attend the DCRC Annual Meeting, Nov. 11-12, in Madison, Wis. The scholarship carries a value of $1,500.

To apply for the DCRC Scholars program, applicants must complete the application form, submit an interest statement that details the applicant’s interest in dairy cattle reproduction, career goals and research project(s), and provide a letter of recommendation. Applicants may also share additional information, such as awards, honors and scholarships received.

Eligible candidates must be a DCRC member and enrolled full time at a college or university in a dairy, animal or veterinary science, microbiology or related program at the time of application deadline, with an area of interest that includes dairy cattle reproduction.

By June 1, applicants will be notified regarding the selection committee’s decision. To learn more about the program and to apply, click here. If you have questions, contact JoDee Sattler at: jodee@dcrcouncil.org.

Webinar features heifer reproduction

The next webinar, scheduled for May 6, starting at 2 p.m. Central Time, features “Preparing heifers for improved reproductive efficiency and production.” Robert “Bob” Corbett of Dairy Health Consultation will lead the webinar.

The American Association of Veterinary State Boards granted one Registry of Approved Continuing Education (RACE) credit for this DCRC webinar. This provides veterinarians with a convenient continuing education opportunity.

Corbett believes that a calf feeding program that enhances an animal’s immune system and growth rate is key to achieving a death loss rate of less than 1 percent (birth to weaning) and average daily gain of more than 2 pounds per day. He will describe feeding recommendations that result in large-framed heifers that aren’t over conditioned and have a higher lean tissue to fat tissue ratio, compared with calves raised on a traditional whole milk or milk replacer program.

During the May 6 webinar, Corbett will address these key topics:

  • Heifer nutrition programs (proper protein to energy ratios) to help heifers reach their genetic potential for growth and future milk production
  • Heifer management systems that foster increased milk production and longevity
  • Formulate rations to maximize rumen microbial growth, which improves feed efficiency and optimizes amino acid balance and protein utilization
  • Strategies to maximize dry matter intake

To register for this webinar, go to: http://bit.ly/DCRCMayWebinar and follow the prompts. As the webinar approaches, you will receive an e-mail with information on how to log in to participate. If you are a DCRC member and cannot attend the live program, you may access the webinar at www.dcrcouncil.org (about two weeks after the webinar). I hope you can join us for this outstanding webinar.

Research Summaries

Association between hoof lesions and fertility in lactating Jersey cows

Lameness is associated with significant economic losses and affects the welfare of dairy cows. Studies of the relationship between lameness and reproductive performance show conflicting effects and focus on lameness defined by locomotion scoring, not hoof lesions (HL). Therefore, to fully understand how lameness affects reproductive performance, the authors’ objectives in this study were to evaluate the association between hoof lesions and fertility in dairy cows.

Treatments

  • At 20 ±3 days in milk (D20), 1,639 lactating Jersey cows were examined and treated for presence of HL and evaluated for body condition score (BCS).
  • Cows were classified at D20 according to HL status as healthy (n = 1,197) or having HL (n = 429).
  • Hoof lesion was also categorized as sole hemorrhage (n = 280), noninfectious HL (sole ulcer, toe ulcer, or white line disease; n = 113), or infectious HL (digital dermatitis and foot rot; n = 36).
  • After exam on D20, cows were managed according to standard farm procedures (estrous detection, presynchronization, and a 5-day Cosynch-72 protocol for cows that failed to show estrus).
  • Cows had their ovaries scanned at 27 and 41 ±3 days in milk (DIM) and were considered cyclic if a corpus luteum greater than 20 mm on at least 1 exam was present.
  • At 120 ±3 DIM (D120), cows were re-examined for HL and BCS.
  • To assess the relationship between the development of HL and fertility, cows were classified as healthy (no HL at D20 and D120; n = 308), cured (any HL at D20 and no HL at D120; n = 72), new HL (no HL at D20 and any HL at D120; n = 597), and chronic (any HL at D20 and D120; n = 226).

Results

  • Compared with healthy cows, cows with HL at D20 had reduced odds of being cyclic (38.3 vs. 51.9%) and a longer interval from calving to first service (58 vs. 51 days).
  • Infectious HL at D20 reduced odds of pregnancy to first service (16.7 vs. 38.3%), compared with healthy cows.
  • Cows with sole hemorrhage at D20 were more likely to lose pregnancies between days 32 and 64 after the first service postpartum (10.5 vs. 5.2%), have a smaller hazard of pregnancy (67.9 vs. 75.5%) at 150 DIM, and more days open (88 vs. 77 days), compared with healthy cows.
  • There was no evidence for a difference in pregnancy hazard at 150 DIM between cows that remained healthy (n = 308) and cows that developed new HL (n = 597).

Conclusions

The authors concluded that hoof lesions at D20, but not new HL, were associated with decreased odds of cyclicity, longer interval from calving to first service postpartum, and reduced pregnancy hazard in Jersey cows. Also, authors recommend new investigations to evaluate the effect of an HL diagnosis in early lactation and management to reduce chronic HL in dairy cows.

Access the paper: https://www.journalofdairyscience.org/article/S0022-0302(20)30103-X/fulltext

 

Early genomic prediction of daughter pregnancy rate is associated with improved reproductive performance in Holstein dairy cows

Genomic testing for selecting replacement heifers in commercial dairy farms has significantly increased recently. Reproductive traits, such as daughter pregnancy rate (DPR), are complex, hard to measure, and lowly heritable traits, and hence they can benefit the most from genomic testing. Therefore, the authors’ objectives in this study were to assess the relationship between early genomic prediction of DPR (GDPR) and pregnancy at the first service (P1), pregnancy at the end of lactation (PEND), number of services for conception (NSFC), days from calving to first service (TP1), and days open (TPEND).

Treatments

  • GDPR, milk production, and reproductive outcomes from 1,401 multiparous and 3,044 primiparous Holstein cows from 4 commercial farms under the same reproductive management were used in the analyses.
  • Animals were genotyped and genomically evaluated as heifers before first breeding; therefore, no phenotypic data were available for predicting genomic merits.
  • GDPR and milk production data were categorized in quartiles.

Results

  • Proportion of cows bred by estrous detection increased linearly from lowest to highest GDPR in primiparous cows.
  • GDPR was positively associated with P1, PEND, NSFC, TP1, and TPEND in both primiparous and multiparous cows. In multiparous cows, the effect of GDPR was 15.7% higher for P1 (47.6% vs. 31.9%), 11.9% higher for PEND (84.9% vs. 73.0%), and 48.0 days shorter for TPEND (139.8 vs. 175.7 days), when comparing the highest quartile with the lowest quartile.
  • GDPR and milk production were only observed for NSFC in primiparous cows, where high-producing cows showed a reduction in NSFC as GDPR increased and low-producing cows showed no relationship between GDPR and NSFC.

Conclusions

Heifers with GDPRs in the highest quartile had fewer days to first service, greater pregnancy at first service, fewer services to pregnancy, fewer days to pregnancy at the end of lactation, and a greater proportion of pregnant cows at the end of lactation. The study demonstrated that GDPR can be effectively used as a predictor of future reproductive performance, reaffirming the benefits of applying early genomic predictions for making accurate early selection decisions.

Access the paper: https://www.journalofdairyscience.org/article/S0022-0302(20)30124-7/fulltext

 

A lateral flow-based portable platform for determination of reproductive status of cattle

Determination of the reproductive status of cows (i.e. estrus, pregnancy, nonpregnancy, and anovulation) are used by dairy and beef farms to optimize reproductive performance. The reproductive status of cows is usually determined by the presence or absence of a functional corpus luteum (CL) at the time of nonpregnancy diagnosis, during synchronization of ovulation protocols, or by estimation of circulating concentrations of the steroid hormone progesterone (P4). Concentrations of P4 can be used to confirm estrus as a method for nonpregnancy diagnosis, determine resumption and cessation of ovarian cyclicity, confirm luteal regression and ovulation, and assign cows to hormonal treatments for synchronization of ovulation. However, fast and accurate detection, and quantification of P4 is not easily accomplished or cost effective. Therefore, the authors’ objective in this study was to develop and validate a tool integrating a disposable fluorescence-based lateral flow immunoassay (LFIA), coupled with a portable imaging device for estimating circulating plasma concentrations of P4.

Methods

  • A competitive fluorescence-based LFIA test strip was developed to measure P4 in bovine plasma.
  • The test was performed by adding 20 μL of plasma and 50 μL of running buffer on a sample pad. After 3 minutes, 45 μL of running buffer was added to initiate sample flow. After allowing 15 minutes to stabilize the colorimetric signal, strips were introduced in an LFIA portable reader wirelessly linked to a laptop to determine P4 concentration based on test-to-control-line signal (T/C ratio).
  • Six experiments in series were performed to evaluate the ability of LFIA to differentiate plasma samples with ≥1 or <1 ng/mL of P4.
  • A calibration curve was constructed using plasma with known concentrations of P4 (0.1 to 3.7 ng/mL; n = 5) in each experiment.
  • The resulting linear equation was then used to determine a T/C ratio cutoff to differentiate samples with ≥1 or <1 ng/mL of P4.
  • Receiver operating characteristic analysis was performed to identify a single cutoff value for T/C ratio that could potentially be used for all batches to evaluate the ability of the platform to assign samples to P4 concentration groups without a calibration curve
  • Plasma samples from lactating dairy cows (n = 58) were tested in triplicate to determine the ability of the LFIA system to differentiate plasma samples with ≥1 or <1 ng/mL of P4 using an RIA for P4 as reference test.

Results

  • Calibration curves showed a linear relationship between T/C ratio and P4 levels (mean coefficient of determination = 0.74; range 0.42 to 0.99).
  • The LFIA assay correctly classified 90% of the samples, with 97% sensitivity, 83% specificity, 85% positive predictive value, and 96% negative predictive value.
  • Agreement between the tests was substantial (kappa = 0.79; 95% confidence interval 0.64 to 0.95).
  • When using a single cutoff value for T/C ratio selected by receiver operating characteristic analysis, sensitivity and specificity to determine CL presence were 97 (95% confidence interval 82 to 99) and 79% (95% confidence interval 60 to 92), respectively.

Conclusions

Data show that the developed portable LFIA system can accurately differentiate plasma samples with ≥1 or <1 ng/mL of P4. The authors also suggest that additional improvements of this assay system may lead to the development of a rapid, low-cost, cow-side tool.

Access the paper: https://www.journalofdairyscience.org/article/S0022-0302(20)30209-5/fulltext

Research Article

DCRC appreciates the generous support of its Platinum sponsors. One Platinum sponsor benefit is the opportunity to publish company-supplied research in a DCRC newsletter. Merck provided the following peer-reviewed research document.

“Ovulation and fertility response to commercially available GnRH products in lactating cows synchronized with the Double-Ovsynch protocol”

M. Luchterhanda, C.A. Gamarrab, R.S. Gennarib, P.D. Carvalhob, R.V. Barlettab, A.H. Souzac,⁎

 

Featured Column

Estrous intensity and duration influence fertility

Unlike pregnancy (a cow is pregnant or she’s not pregnant), estrus has an intensity level. Thus, estrous intensity influences fertility. Similarly, estrous expression and its intensity affects the success of artificial insemination (AI) and embryo transfer (ET).

At the 2019 Dairy Cattle Reproduction Council Annual Meeting, Ronaldo Cerri, University of British Columbia, Vancouver, B.C., Canada, said activity monitors should be used for much more than alerts. “Let’s fine-tune intensity thresholds from activity monitors to better predict fertility and create management tools to improve herd reproductive efficiency.”

The extensive failure to submit cows for AI has a major impact in the pregnancy risk of Canadian herds, but also indicates a unique window of opportunity to improve fertility. Cerri explained that recent studies showed that using different automated activity monitoring (AAM) systems and farms, it was obvious that substantial increases in pregnancies per AI (P/AI) resulted when estrual events had high peak activity (Madureira et al., 2015; Burnett et al., 2018; Madureira et al., 2018) and large decreases in lying time on the day of estrus (Silper et al., 2017).

“Many believe that cows showing ‘good heats’ are more fertile,” said Cerri. “However, this tends to be associated with changes in body condition score (BCS), milk yield, parity and health status. In fact, we have observed greater peak intensity and duration as BCS increased in primiparous cows, but greater P/AI still occurred in spite of those and other risk factors known to affect conception rates.” Consistently, studies (Madureira et al., 2015; Burnett et al., 2018; Madureira et al., 2018) show that cows with high peak intensity have approximately 10 to 14 percentage units greater P/AI than cows with low peak intensity, which represents a 35 percent improvement in fertility.

Capitalize on available data

With today’s AAM technologies, dairy producers can capitalize on these research conclusions. Calibrate AAM to consider a cow’s present conditions. Then, use peak intensity and duration measurements to assist in predicting fertility and improving repro management decisions that involve AAM.

There’s yet another opportunity to analyze AAM data and improve a dairy herd’s repro numbers. AAM systems information can potentially be used to select animals of superior estrual expression and fertility.

Cerri also noted that estrous display (no distinction of intensity) at AI (Pereira et al., 2014) has been associated with reduced pregnancy loss. Similarly, Pereira, et al. (2015) evaluated estrual expression and pregnancy loss. This study showed that estrual expression correlated with reduced pregnancy loss for AI- and embryo transfer- (ET) based programs. “This indicates a possible major modification of the uterine environment as the cause for improved fertility,” reported Cerri. Furthermore, Pereira et al. (2015) reported that cows displaying estrus at AI had decreased pregnancy losses, regardless of the preovulatory follicle’s diameter.

Another study (Madureira et al., 2018) demonstrated the immense effect of estrual intensity on pregnancy loss. “Cows with greater intensity of estrus had significant decreases in late embryonic-early fetal losses,” said Cerri. “This demonstrates that the conceptus-endometrium communication in several stages of early pregnancy are compromised.”

Cerri continued, “Collectively, it seems that the expression of estrus and its intensity have important positive effects in gestation maintenance – particularly by setting up an endometrium environment that is more ideal to receive the conceptus,” he added.

The influence of parity, BCS and milk production

Although studies have shown that a larger follicle is associated with a greater concentration of estradiol in plasma (Cerri et al., 2004), parity, BCS and ultimately milk production are the biggest factors that influence circulating concentrations of estradiol. Cows classified as having high estrual activity had similar preovulatory follicle diameter but slightly greater concentration of estradiol in plasma than cows classified as low activity (Madureira et al., 2015).

The Aungier et al. (2015) study observed no correlation between activity clusters measured by AAM and follicle-stimulating hormone, luteinizing hormone and estradiol profiles. In contrast, a greater peak concentration of estradiol in plasma was associated with standing and estrous-related behaviors. “Ovulation of pre-ovulatory follicles of similar diameter between high and low estrual intensities suggests little change in concentrations of progesterone after AI, but other results indicate that concentrations of progesterone before, at, and after AI are more likely causes of the P/AI and pregnancy loss observations,” remarked Cerri.

Madureira et al. (2018) and Burnett et al. (2018) observed, using different AAM systems, a greater failure of ovulation in cows that displayed low-intensity estrus. “In general, about 5 to 7 percent of cows detected in estrus (via AAM) fail to ovulate,” noted Cerri. “Nearly all of that failure is associated with cows expressing low-intensity estrus.”

Combine timed AI and AAM

“Despite significant progress made with AAM technologies, reproductive programs with intensive use of timed AI (TAI) protocols remain the ‘go to method’ to improve pregnancy rates,” summarized Cerri. However, AAM has made great strides in achieving similar results. Field trials compared different combinations of timed AI and AI based on detected estrus using AAM. Conception risk (30 percent vs. 31 percent) and days to pregnancy (137 and 122 days) did not differ between cows bred via TAI or following estrus detected by an AAM system (Neves et al., 2012).

“The combination of TAI and AAM is perhaps the best reproduction program, because it maintains high rates of conception while submitting a large number of cows to AI. And, to some extent, this combination minimizes the use of pharmacological products,” concluded Cerri. “Timed AI protocols are still necessary as a safeguard for a proportion of cows that would not be inseminated upon estrus up to 100 days in milk.”

Featured Member

(Editor’s Note: For each issue, DCRC interviews a member to learn more about his/her career, involvement with DCRC and thoughts about dairy cattle and reproduction. We encourage you to recommend someone for this feature by contacting JoDee Sattler at: JoDee@dcrcouncil.org)

 

Michael “Mike” Overton
Zoetis
North Topsail Beach, North Carolina
DCRC member since 2006

Raised on a dairy and tobacco farm in North Carolina, Michael Overton grew up next to his maternal grandparents and their dairy farm. During his childhood, Overton’s grandfather stopped by his family’s home every morning on his way home to get breakfast after the first milking.

“Growing up on a dairy farm instilled in me the value of hard work and a love for cows,” said Overton. These values carried over to college, where he attended North Carolina State University and studied animal science prior to attending veterinary school.

Following veterinary school, Overton practiced in a mixed, mostly dairy practice near Statesville, N.C., for eight years. “I had a wide array of interests, but reproductive management of dairy cows topped the list,” he said. Overton’s interest in theriogenology that began in veterinary school continued to grow.

During the latter part of his veterinary clinic practice days, Overton started a dairy certificate program at Penn State University that provided exposure to more great teachers and stimulated his desire for more advanced epidemiological and statistical training.

Next, Overton took a big step and moved his family to California, where he pursued a master’s degree in preventive veterinary medicine and dairy production medicine residency at University of California, Davis. Following this training, he spent six years as a dairy production specialist at the UC Davis Veterinary Medicine Training and Research Center, Tulare, Calif.

“It was in Tulare, while working with a very progressive dairy industry, where I began to dig into the areas of dairy production records, reproductive performance and the economic impact of changes in performance,” said Overton.

Overton’s “next stop” took him back to the Southeast – this time in Georgia, where he served as a University of Georgia professor of dairy production medicine. In this position, he developed a strong passion for veterinary education and mentoring of veterinary and graduate students.

Seven years later, Elanco Animal Health “knocked on his door” – recruiting and challenging him to broaden his outreach efforts further and help even more dairy producers improve their animal health and profitability through beyond-product offerings, such as advanced records analyses and economic modeling. While working for Elanco as a technical consultant, Overton traveled extensively working with producers, veterinarians, and nutritionists to help identify opportunities for improvement in productivity, animal health and ultimately, greater profitability through advanced records analyses and economic modeling of on-farm decision making. “I had a chance to speak at many venues worldwide about subjects ranging from transition disease to heifer production to reproductive management, along with the economic impact of key management decisions,” he said.

In March 2020, Overton joined Zoetis as the Global Precision Dairy Data Lead, reporting into the company’s new Accelerated Growth Businesses group, which includes precision livestock farming. In this new position, Overton will continue to use on-farm data to help drive improved decision making by connecting various systems and data sets into a holistic view of the farm and each individual cow. Working with sensor technology to integrate a continuum of care – predict, prevent, detect and treat – for dairy producers, Overton will derive key management insights that can aid producers and consultants in their day-to-day management decisions to drive improved cow health and greater profitability.

Reflecting on his career – particularly in dairy cattle reproduction – Overton has witnessed dramatic improvements in dairy cattle reproductive performance. He credits this improvement to heightened transition management, nutritional management, genetic selection and appropriate reproductive monitoring and management. “This has resulted in dramatic improvements in the average 21-day pregnancy rate for the majority of dairy herds,” he said.

Proud of his role and influence on the dairy industry, Overton said, “My job provides flexibility to help dairy producers identify opportunities by use of on-farm records analyses and economic modeling tools to provide better information about the value of improved performance to help motivate change. Now, much of my emphasis has moved from simply ‘how do we improve semen delivery’ or ‘how do we improve conception risk’ to more complicated on-farm decision making, such as ‘when should I stop breeding cows’ and ‘what are the impacts of incorrect decision making’.”

A “charter member” of DCRC, Overton served as one of the earliest board members and is the current vice president. “It’s truly a great organization and it has been great to be a part of its growth over time,” he said.

Reflecting on the history of DCRC and its influence in dairy cattle reproduction improvement, Overton said that DCRC provides innovative educational opportunities via its annual conference. “DCRC has expanded its outreach by offering webinars for those who cannot attend the annual meeting in person.”

Overton added, “DCRC offers many valuable resources, but one of the best sources of value is assembling the best and brightest people regarding the topic of dairy cattle reproduction at its annual meeting, where producers, industry professionals, veterinarians and other consultants can discuss innovative and timely topics.” Join us in Madison, Wis., Nov. 11-12, for this year’s DCRC Annual Meeting.

DCRC Webinar Series

2020 DCRC Webinar Series Features Top 2019 DCRC Annual Meeting Topics

Mark your calendars for the Dairy Cattle Reproduction Council’s (DCRC) 2020 webinar series. These highly regarded sessions offer access to high-quality information and interaction with industry experts to attendees from across the United States and around the world, all from the comfort of their farm or office. The webinars feature top-rated topics from the 2019 DCRC Annual Meeting.

Save these dates and times:

  • Bob Corbett, Dairy Health Consultation, presents “Preparing heifers for improved reproductive efficiency and production.”

May 6, at 2 p.m. Central time

  • Luis Mendonca, Merck Animal Health, presents “Maximizing fertility while minimizing timed AI use.”

June 26, at 2 p.m. Central time

  • Mark Kirkpatrick, Zoetis, presents “Data organization yields positive returns.”

Aug. 7, at 2 p.m. Central time

The American Association of Veterinary State Boards granted one Registry of Approved Continuing Education (RACE) credit for the May 6 DCRC webinar. This provides veterinarians with a convenient continuing education opportunity.

For more information about the DCRC webinars, e-mail Paula Basso, DCRC Education Committee chair, at: paula.basso@zoetis.com or e-mail DCRC at: dcrc@dcrcouncil.org.

To register for a webinar, please visit www.dcrcouncil.org/webinars and follow all prompts. As the webinar approaches, you will receive an e-mail with information on how to log in for attendance. If you are a DCRC member and cannot attend the ”live” webinar, you may access it (and all past webinars) at www.dcrcouncil.org/webinars.

The Dairy Cattle Reproduction Council is focused on bringing together all sectors of the dairy industry – producers, consultants, academia and allied industry professionals – for improved reproductive performance. DCRC provides an unprecedented opportunity for all groups to work together to take dairy cattle reproduction to the next level.

Industry Calendar