Newsletter – 2020 – December

President's message

From the DCRC President’s Desk
By Michael Overton

What a year! 2020 has been full of often unexpected disappointments and even some pleasant surprises. And, not surprisingly, we at DCRC were impacted and had to pivot from an in-person meeting to a virtual one, but what a great meeting it was! Though I missed the opportunity to interact face-to-face with old and soon-to-be new friends, the flexibility and adaptability shown by our DCRC group, our speakers, our sponsors and our members resulted in a very well attended meeting and awards presentation.

I first want to thank DCRC’s 2020 Program Chair Eduardo Ribeiro and Program Vice Chair Ralph Bruno. These two assembled a very good program and poster session that resulted in some great continuing education opportunities and significant question and answer sessions. The moderators did a nice job facilitating the interactions via typed questions from viewers. One person that also deserves to be recognized for all of his hard work is Jeff Stevenson. Jeff does a great job as our editor and reviewer for the proceedings papers that our speakers submit to support their oral presentations. Next, I want to thank Glaucio Lopes for all his hard work at organizing and assembling our sponsorship support. Without the gracious support of our sponsors, an organization like DCRC could not survive and continue to provide the great educational opportunities that are characteristic of DCRC.

Congratulations to the 24 dairy operations that were recognized this year for their excellent reproductive management efforts. The level of performance achieved by these herds was unheard of not that many years ago. Their dedication and work, day in and day out, is truly commendable. A huge amount of thanks is extended to Corey Geiger of Hoard’s Dairyman and the judges for their hard work that made these awards possible. Thanks also to the numerous people who nominated many outstanding dairies for consideration this year. As we look toward 2021, I want to encourage you to identify herds that are deserving of recognition for their repro performance and nominate them next year.

Top honors (Platinum recognition) went to: Davis Family Dairies (Tom Jinkinson, farm manager, Mark, Mitch and Marty Davis, owners), Nicollet, Minn.; Hendriks Dairies (Henry and Tyler Hendriks), Brucefield, Ont., Canada; High Noon Dairy (Jody Cole, farm manager, Pete and Dana Bouma, and Jim and Katie DiGangi, owners), Hereford, Texas; Holmesville Dairy (Tim and Travis Holmes), Argyle, Wis.; Patterson Farms (Paul and Jody Colgan, herd managers, Jon and Julie Patterson, and Dan Young, owners), Auburn, N.Y.; and Riverside Dairy (Andy Fisher and Tom and Jean Tienor), Reedsville, Wis.

I would also like to recognize our DCRC Scholar – Tony Carreira Bruinjé, a doctorate degree student at the University of Guelph, Guelph, Ont., Canada. Tony, a veterinarian from Brazil, was selected from six applicants from four universities. The DCRC board of directors’ vision is to support graduate students studying dairy, animal or veterinary science, microbiology, or a related program, with an area of interest that includes dairy cattle reproduction and fertility.

As the year winds down, we are also excited to announce the members of our board of directors – President Michael Overton, Zoetis; Vice President Matt Utt, Select Sires; Secretary-Treasurer Jeff Stevenson, Kansas State University; Past President Julio Giordano, Cornell University; and director members Luis Mendonca, Merck Animal Health; Natalia Martinez-Patino, Zoetis; and Eduardo Ribeiro, University of Guelph. Committee chairs include: Awards Chair Corey Geiger, Hoard’s Dairyman; Program Chair Ralph Bruno, Zoetis; Education Chair Luciano Caixeta, University of Minnesota; Membership Chair Fernanda Ferreira, University of California, Davis Veterinary Medicine Teaching & Research Center; and Nomination Chair Giordano. DCRC thanks outgoing board member Glaucio Lopes, Alta Genetics, for his devoted service to DCRC.

Finally, as the incoming president of DCRC, I want to thank our Past President Julio Giordano for his leadership efforts throughout this past year. His support and dedication for the DCRC organization is outstanding and I hope to continue his efforts to grow and expand DCRC and its international reach. If you have ideas or suggestions on how to improve the effectiveness, reach and sustainability of DCRC, please share your ideas with me by e-mail at: Michael.Overton@Zoetis.com.

Next year’s DCRC Annual Meeting is set for Nov. 10-11, in Kansas City, Mo. Watch the DCRC website – www.dcrcouncil.org – for program updates.

Research Summaries

Metabolic markers for purulent vaginal discharge and subclinical endometritis in dairy cows

Bogado Pascottini, and S.J. LeBlanc

The objective of this study was to compare blood biomarkers for inflammation, liver activity, and mineral and energy status throughout the transition period in cows that were diagnosed with purulent vaginal discharge (PVD) and subclinical endometritis (SCE).

Materials and methods:

Blood samples were collected on days -7, 1, 3, 5, 7, 14±1, 21±1, and 35, relative to calving. Serum was harvested after centrifugation and used to measure the concentrations of haptoglobin (Hp), non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), total calcium, total protein, albumin, globulin, cholesterol, urea, glucose, gamma-glutamyl transferase (GGT), aspartate aminotransferase (AST), glutamate dehydrogenase (GLDH), and insulin-like growth factor-1 (IGF-1). Purulent vaginal discharge and subclinical endometritis were diagnosed at 35 days in milk.

Results

  • Serum Hp was greater in cows that developed SCE during the first 2 weeks post-partum when compared with healthy cows, and greater at days 7 and 35 when comparing PVD cows to healthy animals.
  • Serum NEFA and BHB at day 15 post-partum were greater in SCE cows when compared with PVD and healthy cows.
  • Healthy cows had greater IFG-1 concentrations pre-partum when compared with cows with PVD. IFG-1 concentrations at 14 days post-partum were greater in healthy and PVD cows when compared with SCE.
  • Healthy cows had greater albumin concentrations than PVD cows at 14 days post-partum and at 35 days post-partum when compared with SCE cows.
  • When compared with healthy cows, cholesterol was lower in SCE cows at 14, 21, and 35 days post-partum, and lower in SCE cows at 35 days when compared with PVD cows.
  • Serum total calcium was lower in SCE cows during the week before calving when compared with healthy cows. Healthy cows also had greater total calcium concentrations at 7 and 14 days post-partum when compared with PVD cows.
  • No differences were observed for the other metabolites.

Conclusions

These results suggest that differences in the energy metabolism and inflammatory response of post-partum dairy cows precede the diagnosis of inflammatory uterine diseases. The results also highlight the importance of successful transition from late gestation to early lactation for the maintenance of uterine health in dairy cows.

Access the paper here.

 

Effect of reproductive management programs for first service on replacement dairy heifer economics

Masello, M.M. Perez, G.E. Granados, M.L. Stangaferro, B. Ceglowski, M.J. Thomas, and J.O. Giordano

Heifer-rearing costs represent 15 to 20% of total operating expenses (Harsh et al., 2001; Karszes, 2014). Optimizing age at first calving to reduce days on feed and incorporate heifers into the milking herd earlier can reduce raising costs and the time required for a dairy cow to attain positive lifetime cash flow (Ettema and Santos, 2004). Therefore, the objective of this study was to evaluate cash flow for dairy heifers managed for first service with programs that relied primarily on insemination at detected estrus (AIE), timed AI (TAI), or a combination of both.

Treatments

  • Holstein heifers from 2 commercial farms were enrolled in 1 of 3 treatments to receive first service with sexed semen after the beginning of the AI period (AIP) at 12 months of age:
    • PGF+AIE (n = 317): AIE after PGF2α injections every 14 days (up to 3), starting at the beginning of the AIP; heifers not AIE 9 days after the third PGF2α were enrolled in the 5-day-Cosynch (5dCP) protocol
    • ALL-TAI (n = 315): TAI after ovulation synchronization with the 5dCP protocol
    • PGF+TAI (n = 334): AIE after 2 PGF2α injections 14 days apart (second PGF2α at beginning of AIP). If not AIE 9 days after the second PGF2α, the 5dCP protocol was used for TAI. After first service, heifers were AIE or received TAI after the 5dCP with conventional semen.
  • Individual heifer cash flow (CF) for up to a 15-month period (day 0 = beginning of AIP) was calculated using reproductive cost (rearing only), feed cost (rearing only), income over feed cost (lactation only), calf value, operating cost, and with or without replacement cost. 

Results

  • Time to pregnancy was reduced for the ALL-TAI versus the PGF+AIE treatment (1.20; 1.02–1.42; hazard ratio and 95% CI), but it was similar for ALL-TAI and PGF+TAI (1.13; 0.95–1.33) and the PGF+AIE and PGF+TAI treatments (1.07; 0.91–1.25).
  • The proportion of heifers not pregnant by 100 days did not differ (PGF+AIE = 7.0%; PGF+TAI = 6.5%; ALL-TAI = 6.8%).
  • When including replacement cost, CF ($/slot per 15 months) differences were $51 and $42 in favor of the PGF+TAI and ALL-TAI compared with the PGF+AIE treatment, and $9 in favor of the PGF+TAI compared with the ALL-TAI treatment but did not differ statistically.
  • The difference in CF between the PGF+AIE with the PGF+TAI and ALL-TAI treatment was the same (i.e., $15) and favored programs that used more TAI when heifers that were replaced were excluded to evaluate the effect of timing of pregnancy differences only.

Conclusions

The authors concluded that submission of heifers for first service with TAI only or TAI in combination with AIE reduced rearing costs and increased revenue during lactation, resulting in increased cash flow under fixed (not statistically significant) or simulated variable market conditions. The higher costs of the reproductive program due to use of TAI were offset by the positive effect of earlier pregnancy on cash flow of replacements heifers.

Access the paper:  https://www.journalofdairyscience.org/article/S0022-0302(20)30944-9/fulltext

 

Differing planes of pre- and postweaning phase nutrition in Holstein heifers: II. Effects on circulating leptin, luteinizing hormone, and age at puberty

T.C. Bruinjé , J.P. Rosadiuk, F. Moslemipur, H. Sauerwein, M.A. Steele, and D.J. Ambrose

Heifer age at first calving between 22 and 24 months is associated with improved lifetime productivity and overall economic return (Heinrichs et al., 2017). Studies have demonstrated the relationship between early-life nutrition and reproductive development in dairy heifers, but the relationships of pre- and postweaning nutrition with physiology related to onset of puberty is still not fully known. Therefore, the authors’ objective was to investigate the effects of differing planes of pre- and postweaning nutrition on prepubertal serum leptin concentrations, luteinizing profiles (LH) profiles, and age at puberty in Holstein heifers. 

Treatments

  • 36 Holstein heifer calves were randomly preassigned to receive:
    • 1 of 2 preweaning dietary treatments: low (5 L of whole milk daily; 2.5-L meals at 06:15 and 16:30 hour [h]; n = 18) or high (10 L of whole milk daily; 2.5-L meals at 06:15, 11:30, 16:30, and 22:00 h; n = 18) until 21 ± 1 days of age. Heifers were then moved to a group pen and fed the same preweaning plane of nutrition with a stationary automated feeder, with ad libitum access to starter/concentrate and straw, and weaned on day 60 after a 10-day weaning transition with a 10% daily decrease in the total milk fed.
    • 1 of 2 postweaning dietary treatments: low (70:30 concentrate:straw ratio dry total mixed ration; n = 18) or high (85:15 concentrate:straw diet; n = 18) from 11 to 25 weeks of age.
    • Serum leptin concentrations were measured every 2 weeks from 1 to 25 weeks of age, and LH profiles were determined both at week 15 and 25, based on sequential blood samples taken every 12 minutes over 10 h. Starting at 26 weeks of age, ovaries were examined weekly by transrectal ultrasonography until first ovulation (puberty) was confirmed.

Results

  • Heifers from the high preweaning plane diet had greater leptin concentrations (2.9 nm/mL) during the preweaning phase than those fed the low plane (2.6 ng/mL). In the postweaning phase, leptin was greater in heifers fed the high compared with the low postweaning diet (3.2 ng/mL vs. 2.5 ng/mL).
  • Amplitude (2.1 vs. 1.7 ng/mL), peak (2.2 vs. 1.8 ng/mL), and duration (35.6 vs. 28.7 min) of LH pulses assessed at week 15 were greater in heifers offered the high than those offered the low preweaning plane, but no nutritional effects were observed on LH pulses at week 25.
  • The likelihood of attaining puberty by 30 weeks of age was greater (hazard ratio = 3.8; 95% CI = 1.0 to 14.4) in heifers fed the high postweaning plane compared with the low plane. The proportion of heifers that attained puberty by 30 weeks of age was 25.6 and 31.5% for low and high preweaning dietary groups, and 16.6 and 44.4% for low and high postweaning diet groups, respectively.
  • Heifers achieving puberty by 30 weeks also had greater leptin concentrations from weeks 1 to 25, for every 1 ng/mL increase in circulating leptin at weeks 15 and 25; days to puberty were estimated to decrease by 22 and 13 days, respectively. 

Conclusions

The authors concluded that increasing the preweaning plane from 5 to 10 L/d of whole milk increased serum leptin concentrations at weeks 1, 3, and 5, and LH pulse amplitude, peak, and duration at week 15. Increasing the postweaning plane from 70 to 85% of concentrate resulted in greater circulating leptin concentrations, which may be linked to an earlier onset of puberty.

Access the paper: https://www.journalofdairyscience.org/article/S0022-0302(20)30870-5/fulltext

Featured Column

Genomic selection helps improve dairy cattle fertility, speed of genetic improvement

Not so long ago, Holstein breeders faced declining Holstein cow fertility and some breeders struggled to meet cattle replacement needs. Fast forward 12 years or so – to now – when Holstein cattle reproduction is steadily improving and many have excess replacements and/or use beef semen to prevent the birth of unnecessary heifers.

During the Dairy Cattle Reproduction Council Annual Meeting, John Cole, with the Animal Genomics and Improvement Laboratory, along with Peter Hansen, University of Florida, discussed the progress made in dairy cattle fertility, with a focus on genomic selection. “Genomic selection was a critical tool for stopping the decline in Holstein cow fertility,” said Cole. “Fertility of the Holstein cow is now slowly but steadily improving.”

How does genomics help improve cattle fertility? Dairy producers can use bulls with high genomic breeding values for fertility traits. Improvements can be realized in one generation. “The availability of low-cost, high-density genetic marker panels and whole-genome sequence data have allowed researchers to identify genes associated with large effects on fertility, and to dissect the biology of gametogenesis, fertilization and development,” Cole explained.

Past: Milk yield up; fertility down

To reflect a bit on progress made in Holstein cattle fertility, daughter pregnancy rate (DPR) reached a low of 24.1 percent in 2005 – down from a high of 39.5 percent in 1959. This represents an increase of 1.3 days open per year. Basically, fertility declined as milk yield increased.

In 2003, fertility was added to the Lifetime Net Merit selection index with a weight of 7 percent. Genomic selection was introduced in 2009. Today, fertility traits (DPR, heifer conception rate [HCR] and cow conception rate [CCR]) receive 10 percent of the weight in the index.

Improving fertility via genetics can be challenging. DPR evaluations are based on observations of days open, whereas HCR and CCR are based on breeding and pregnancy diagnosis data. The low heritabilities of these traits indicate that the environment plays a much bigger role in their expression than genetics.

Figure 1. Trends in U.S. Holstein breeding values for DPR, HCR and CCR for bulls and cows for animals born 1957 to 2019.

In general, U.S. dairy producers and allied industry quickly adopted genomic selection. One big change is the decrease in generation interval by almost half. This increased the rate of genetic gain substantially because the breed largely shifted from the predominant use of progeny-tested sires 5 to 7 years old to  using sires less than 4 years old.

Be confident in genomic evaluations

Should dairy producers be concerned about sire evaluations changing a lot from one evaluation run to another? Cole said the simple answer is, “no.” Admittedly, some early genomic evaluations changed a lot. “Today, the statistical methodology is mature and such changes are rarely seen.”

To confirm this claim, Cole explained that a study of 4,445 Holsteins from four commercial dairies showed that cows with genomic predicted transmitting ability (PTA) for DPR in the top quartile had greater pregnancy rates, fewer days open and fewer services to conception than cows with PTA in the bottom quartile. Similarly, cows with PTA for DPR >1 had a higher pregnancy rate at first service, fewer services per conception and fewer days open than cows with a DPR <-1.

While embryo transfer (ET) has been used on some dairies for nearly a half century, its reach continues to expand. The potential of ET to increase the number of offspring produced by genetically elite females is of growing importance. “What will be essential to make ET use more widespread is to reduce the costs of embryo production and increase the effectiveness of the procedure for achieving pregnancies,” Hansen reported. A recent reported advance in cryopreservation of embryos produced in vitro – if repeated – could be an important step in that direction.

Thus, continued development of reproductive technologies will help dairy producers realize increased rates of genetic gain. Additionally, other current and anticipated advances in reproductive management, including timed artificial insemination and development of remote sensing technologies, may allow dairy producers to improve dairy cattle fertility and increase dairy farm profitability.

To read the complete proceedings paper that Cole and Hansen prepared, log into the DCRC Members Only webpage and click on the “Proceedings” icon. References can be found in the proceedings paper. Also, DCRC Annual Meeting registered attendees can access the recording of this presentation.

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)

 

Luciano Caixeta
University of Minnesota College of Veterinary Medicine
St. Paul, Minnesota
DCRC member since 2017

Born and raised in a strong agricultural state in Brazil, Luciano Caixeta is an assistant professor at the University of Minnesota’s College of Veterinary Medicine, department of veterinary population medicine. His family owns a small pasture-based dairy herd, but he gained most of his bovine experience on large-scale, cow-calf feedlot operations. Like Luciano, his father is a veterinarian, who specializes in nutrition and reproductive management of beef cattle. “From a young age, I shadowed him every time I had the opportunity,” said Luciano.

In 2008, Luciano earned a Doctor of Veterinary Medicine degree from his hometown veterinary school – Universidade Federal de Goiás. Shortly after graduation, he moved to the United States and completed a residency in Population and Ambulatory Medicine at Cornell University, Ithaca, N.Y. In 2017, he completed a doctorate degree, also from Cornell University.

At the University of Minnesota, Luciano spends most of his time on research projects. He primarily focuses on the metabolic adaptation of the dairy cow. However, he also does quite a bit of clinical teaching for senior veterinary students. In addition, Luciano co-coordinates the college’s bovine theriogenology clinical rotation and also teaches the dairy production medicine didactic rotation.

Luciano developed an interest in dairy cattle reproduction, due to its importance to the cattle industry. “Successful reproductive programs are what keep cattle businesses profitable,” he stated. “Also, it’s the industry’s way to produce high-quality protein – and food in general – for the planet’s growing population.”

Currently serving as DCRC’s education chair, Luciano said he has learned a lot about reproduction by attending DCRC meetings and webinars. “I advise all my students who have some interest in reproduction to join the organization, because this is THE place to get all repro information,” he said. “In the academic environment, DCRC meetings are great for the exchange of ideas and knowledge. Plus, the meetings serve as a springboard for new advancements in repro technologies and knowledge.”

Luciano added, “Out of the academic environment, DCRC plays a crucial role in bringing the newest knowledge and advancements in dairy cattle reproduction to producers and people in the field.”

Looking forward, Luciano hopes DCRC continues to grow and be the leading source of science-based and field-proven resources on dairy cattle reproduction.

Click here to learn more about Caixeta’s research interests.

DCRC Webinar Series

DCRC webinar, presented in Spanish, highlights impact of health on fertility

“Revisiting the impact of overall and reproductive health on fertility: Phenotypes and genotypes” (“Revisitando el impacto de la salud general y reproductiva en la fertilidad: Fenotipos y genotipos”), presented in Spanish, headlines the next Dairy Cattle Reproduction Council (DCRC) webinar. The free webinar starts at 2 p.m. Central time on Dec. 4. Pablo Pinedo, Colorado State University assistant professor, will serve as the instructor for this one-hour webinar.

During the webinar, Pinedo will discuss:

  • Incidence of early lactation diseases in different seasons and geographic regions
  • Effect of combinations of health-related events on fertility and survival
  • Potential use of reproductive indices
  • Interesting traits for genetic selection

Pinedo earned his Doctor of Veterinary Medicine degree from the University of Chile and doctorate degree from the University of Florida’s College of Veterinary Medicine (UFCVM). In 2011, he completed a residency in food animal reproduction and medicine at UFCVM. Next, Pinedo spent four years as an assistant professor at Texas A&M University – Texas A&M AgriLife Research – College of Veterinary Medicine. Currently, he serves as an assistant professor in Colorado State University’s animal sciences department.

To register for this webinar, go to: https://bit.ly/DCRCDecWebinar and follow the prompts. As the webinar time 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).

For more information about DCRC’s webinars, e-mail Luciano Caixeta, DCRC Education Committee chair, at: lcaixeta@umn.edu or e-mail DCRC at: kellie@dcrcouncil.org.

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