Newsletter – 2019 – December

Carryover effects of pre- and postweaning planes of nutrition on reproductive tract development and estrous cycle characteristics in Holstein heifers

In recent years, research has shown the importance of calf growth and development early in life because it can result in long-term economic returns – due to reduced mortality, younger age at first breeding and improved productivity during lactation. In this study, Bruinje et al. (2019) aimed to investigate carryover effects of pre- and postweaning planes of nutrition on prepubertal reproductive tract development and on postpubertal estrous cycle characteristics in Holstein heifers.

Treatments

At birth, heifer calves (n=36) with the same colostrum management were randomly preassigned to either a low or high (5 or 10 L of whole milk/day, respectively) preweaning diet from 1 to 7 weeks of age, and to either a low or high (70 or 85% of concentrate dry total mixed ration, respectively) postweaning diet from 11 to 25 weeks of age in a 2 x 2 factorial design.

Outcomes of interest were prepubertal endometrial thickness and ovarian follicular population beyond 26 weeks of age, and postpubertal ovarian dynamics and estrous activity during the estrous cycle.

Results

Prepubertal phase:

• Heifers fed the high postweaning diet had greater endometrial thickness and largest follicle size, compared with those in the low postweaning diet.
• Heifers fed the high preweaning diet had a greater number of 6- to 9-mm follicles, compared with those in the low preweaning diet.
• Heifers fed the high postweaning diet had more >9-mm follicles, compared with those in the low postweaning diet.

Postpubertal phase:

• Heifers fed the high postweaning diet had more >9-mm and antral follicles, compared with those in the low postweaning diet.
• Heifers fed the high postweaning diet had lower P4 at 4 days preceding luteolysis, compared with those in the low postweaning diet.
• Overall, corpus luteum and P4 dynamics did not differ among pre- or postweaning treatments.

Conclusions

The authors found a positive carryover effect by increasing the preweaning level of nutrition from 5 to 10 L of whole milk/day on prepubertal follicular growth. Also, using 85% of concentrated dry total mixed ration during postweaning advanced reproductive development through greater endometrial thickness and follicular growth in the prepubertal phase and increased the population of antral follicles in the postpubertal estrous cycle of Holstein heifers, compared with a 70% of concentrated total mixed ration.

Access the paper: https://www.journalofdairyscience.org/article/S0022-0302(19)30794-5/fulltext

Association of concentrations of beta-carotene in plasma on pregnancy per artificial insemination and pregnancy loss in lactating Holstein cows

Placental insufficiency is a potential cause of embryonic mortality. It is known that proper blood-vitamin concentrations are essential for normal reproductive function. Beta-carotene may have potential reproductive benefits. This antioxidant is a precursor for vitamin A, which is known to be beneficial in maintaining cellular membranes and functions, and neutralizing reactive oxygen species, which plays a role in protecting the oocyte and embryo from oxidative stress. In addition, beta-carotene prevents inactivation of the cholesterol cleavage enzyme, increasing activity of this enzyme and allowing for increased production of steroid hormones. Therefore, Madureira et al. hypothesized that cows with higher plasma beta-carotene concentrations will have improved fertility and fewer pregnancy losses than cows with lower plasma beta-carotene concentrations.

Treatments

Holstein cows (n=364) were enrolled in a trial (143 primiparous and 221 multiparous) and all cows were assigned to a timed artificial insemination (AI) protocol based on estradiol and progesterone (399 AI events).

• Blood samples were collected at the moment of AI and at 24 and 31 days post-AI (samples on 31 days post-AI were collected only from cows that were diagnosed pregnant).
• Body condition scores (BCS) were recorded and plasma beta-carotene was quantified from blood samples taken at the time of AI.
• Pregnancy-associated glycoproteins (PAG) were analyzed in blood samples taken at 24 and 31 days post-AI of pregnant cows.
• Pregnancy diagnosis was performed by ultrasound 31 and 60 days post-AI, and milk production was collected for the entire experimental period.

Results

• Cows classified as thin (<2.75 BCS) tended to have lower concentrations of beta-carotene at AI when compared with those classified as moderate (3.00; 3.8 ± 0.1 vs. 4.3 ± 0.1 mg/mL).
• Concentrations of beta-carotene were greater in multiparous cows, compared with primiparous cows.
• There was no correlation between concentration of beta-carotene and milk production.
• When plasma beta-carotene was categorized in quartiles, cows in the first quartile had lower pregnancy/AI and higher pregnancy losses, when compared with cows that were in the second, third, and fourth quartile (pregnancy/AI = 19.2 ± 4.5, 33.7 ± 4.7, 36.9 ± 5.0, and 39.8 ± 5.4%, respectively; pregnancy losses = 41.9 ± 4.8, 20.4 ± 3.7, 22.1 ± 4.1, and 15.7 ± 4.2%, respectively).
• There was no association between concentrations of beta-carotene at AI and PAG at 24 days post-AI, but cows with greater concentrations of beta-carotene at AI were more likely to have greater concentrations of PAG at 31 days post-AI.

In conclusion, the concentration of beta-carotene at AI was affected by BCS and parity. Cows with higher concentrations of plasma beta-carotene at AI had greater pregnancy/AI, lower pregnancy losses, and greater concentrations of PAG at day 31 post-AI. This suggests it may be associated with placental function in lactating dairy cows.

Access the paper

https://www.sciencedirect.com/science/article/pii/S0093691X19304534

Postovulatory treatment with GnRH on day 5 reduces pregnancy loss in recipients receiving an in vitro produced expanded blastocyst

Garcia-Guerra et. al. hypothesized that administration of gonadotropin releasing hormone (GnRH) on day 5 of the estrous cycle in embryo transfer (ET) recipients would increase progesterone (P4) concentrations, embryo size, and improve fertility. The optimal timing for induction of ovulation with GnRH has not been adequately explored for trials with recipients of in vitro produced (IVP) embryos.

Current treatments of lactating dairy cows with human chorionic gonadotropin (hCG) on day 5 of the estrous cycle caused the first significant increase in P4 by day 8 with the most dramatic effects at day 10 and day 12, and induction of ovulation on the day of ET causes an increase in P4 at days 12 to 14 of the cycle, which may be too late to have optimal effects on fertility. Treatment with GnRH on day 5 requires an extra handling of recipients but could produce an earlier increase in P4, compared with recipients treated on day 7. The authors’ objective was to evaluate the effect of administering 200 mg of GnRH on day 5 (in the afternoon) after a protocol that synchronizes ovulation, on accessory corpus luteum (CL) formation, serum P4 concentrations, and fertility of heifers receiving IVP embryos.

Treatments

Holstein and crossbred Holstein heifers (n=1,562) were synchronized using a modified 5-day CIDR-Synch protocol: Day 8, CIDR inserted; Day 3, CIDR removed and PGF2a (500 mg cloprostenol) treatment; Day 2, second PGF2a; Day 0, GnRH (G1, 100 mg gonadorelin acetate) to induce ovulation. On Day 5 in the afternoon, heifers were assigned, in a completely randomized design, to one of two treatments: Control (untreated; n=767) or GnRH (200 mg; n=794).

Results

• Ovulation to Day 5 GnRH, defined by the presence of an accessory CL on Day 12, was 83.9% in GnRH-treated heifers vs. 3.3% in controls.
• On Day 12, P4 was greater in GnRH-treated heifers (7.2 ± 0.1 ng/ml) vs. controls (6.0 ± 0.1 ng/ml).
• There was greater P/ET at day 33 and day 60 of pregnancy for stage 7 than stage 6 embryos.
• Treatment with GnRH did not alter P/ET with either embryo stage but decreased pregnancy loss between day 33 and day 60 in heifers receiving Stage 7 embryos (11.6 vs 27.6%).
• Although there was no GnRH effect on embryo size, the presence of an accessory CL was associated with larger amniotic vesicle volume in recipients of stage 7 embryos. In addition, greater pregnancy-specific protein B (PSPB) was linked to greater amniotic vesicle volume and to reduced pregnancy loss.

In conclusion, induction of an accessory CL by treatment with GnRH on day 5 increased circulating P4 and was associated with a reduction of pregnancy loss in recipients of stage 7 IVP embryos. However, there was no indication of an effect in recipients of stage 6 embryos. This effect was particularly dramatic when evaluating pregnant recipients that had an accessory CL on day 33 compared with recipients without an accessory CL (>50% reduction in pregnancy loss). Analysis of embryo size also indicated that recipients of stage 7 embryos that had an accessory CL had greater embryo size than recipients without an accessory CL. Use of GnRH near the time of ET may be a practical treatment for reducing pregnancy loss in recipients that receive stage 7 IVP embryos.

Access the paper

https://www.sciencedirect.com/science/article/pii/S0093691X19301347

Proactive on-farm protocols help secure consumer confidence

“Many consumers make decisions based on emotions, not science,” said Katie Mrdutt, Food Armor executive director, at the 2019 Dairy Cattle Reproduction Council (DCRC) Annual Meeting. “Sharing our story and our ‘why’ is a way to connect with these individuals.”

Mrdutt believes dairy producers and bovine veterinarians hold responsibility for food safety and antimicrobial stewardship. “As a highly respected resource for animal health, the public looks to veterinarians to help ensure that products the dairy industry produces are safe and free of violative drug residues.”

In addition, veterinarians help ensure that producers are only using antimicrobials when absolutely necessary. When antibiotics are used, veterinarians and producers must follow the label to prevent antibiotic residues and combat antibiotic resistance.

Commit to ongoing improvement

“As consumer preferences and demands change, producers need to be committed to ongoing improvement in their production practices to maintain and grow market access,” said Mrdutt. “Demonstrating a continuous commitment to producing safe products through accountability and traceability helps maintain and open new markets – both nationally and internationally.”

To help demonstrate the why and provide DCRC members with some tools to share the judicious use of antibiotics story, Mrdutt turned to Simon Sinek’s philosophy that “People don’t buy what you do, they buy why you do it.” She encourages dairy producers, veterinarians and industry partners to find their why, their passion and use it to connect with consumers’ whys. “Doing so will bring us closer together,” she said.

Mrdutt explained that Food Armor focuses on providing solutions to ensure antimicrobial stewardship on farms and taking a unique Hazard Analysis and Critical Control Point (HACCP) approach. The drug use HACCP plan requires identifying and defining six areas significant to drug use that are unique to each dairy.

1. Veterinarian-client-patient-relationship (VCPR)

The veterinarian of record and farm owner assign roles and responsibilities that establish lines of communication among all members of the VCPR team.

2. Drug list

This list includes all drugs on the farm and defines exactly how each drug will be used in specific situations or management groups.

3. Protocols

The veterinarian of record develops treatment plans for commonly occurring, easily recognizable conditions. The veterinarian of record provides instructions for the care of these conditions in his/her absence.

4. Standard operating procedures (SOPs)

These procedures precisely define procedures for animal care, including animal identification, residue avoidance, drug administration and euthanasia.

5. Records

Records provide the veterinarian of record and the farm owner a means for oversight of on-farm drug use. The recording method must include a treatment log for every treatment and a permanent medical history for every animal. The permanent record should provide information that allows farm management to make medical decisions for the individual animal and the entire herd.

6. Oversight

Veterinary oversight includes continuous monitoring of hazards and identification of potential improvements to the animal care plan. Oversight is an integral component for validating the VCPR and providing accountability. Ultimately, this results in increased consumer confidence.

Mrdutt described the Food Armor program’s “HACCP plan” as a win-win situation for dairy producers and veterinarians. Plus, processors, marketers and consumers can be added to this win-win equation.

Helps the bottom line

“With veterinarian oversight, producers can evaluate their animal drug use and, in most cases, find economic gains when using lower amounts of drugs (follow label treatments) with shorter withholds,” said Mrdutt. This results in less non-saleable milk and thus more milk income.

Furthermore, the HACCP plan helps producers achieve added value through risk management. Potential gains come via:

• Continual review of on-farm protocols
• Reduction of protocol drift
• Eliminating treatment of incurable animals
• Employee training and evaluation
• Improved treatment records

In addition, Food Armor’s benefits do not end at the farm. Everyone in the food chain – from producers to processors to retailers to consumers – benefits from a safe and high-quality raw food product. “The product can only be as good as its raw components,” said Mrdutt.

Developing a HACCP plan is a great step toward strengthening consumer confidence in livestock production and milk and meat safety. “As an industry, we can stand together and join the conversation,” said Mrdutt.

(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)

Alexandre “Alex” L.A. Scanavez
Kansas State University PhD Candidate (graduating in December 2019) and 2019 DCRC Scholar
DCRC member since 2016

This past November, I attended the DCRC Annual Meeting in Pittsburgh. Even though this was my fourth year attending this meeting, this time it was a different experience compared with previous years. I was a month away from finishing my PhD and was honored as a DCRC Scholar. This program was a DCRC initiative that started in 2019, which aims to recognize graduate students involved in research projects related to dairy cattle reproduction. As one of the award recipients, I attended the meeting with my travel expenses paid but also had the privilege to present my research to dairy producers, allied industry representatives, and researchers. The research highlighted some of the work our laboratory at Kansas State University has been conducting. Both studies presented were related to strategies to assess heat stress severity during the dry period and to optimize milk yield of cows exposed to heat stress during the dry period. Because these studies were designed to be applicable in large commercial dairy herds, I was excited to receive questions and feedback from dairy producers and consultants who visited with me about the studies presented. I made sure to write down comments and suggestions, which will certainly be useful for future studies. I am positive that presenting these studies and being one of the DCRC Scholars helped me to expand my professional network during the meeting.

Besides the networking opportunities, the 2019 DCRC Annual Meeting offered a great educational program. Important topics were presented by speakers who are recognized specialists in their fields, which made this meeting a great opportunity to stay up to date with the most recent research regarding dairy cattle reproduction. In my opinion, besides the topics and speakers selected, the most important characteristic of the DCRC educational program was the practical approach to the various topics presented. Of course, I love science and scientific articles, but I believe that science needs to serve a purpose which, in this case, is to help dairy producers and consultants optimize reproductive performance in their herds. It was clear in all sessions that the speakers were not only presenting data but also trying to recommend how to apply the concepts being presented to optimize reproduction in commercial dairy herds.

In addition to presenting part of my research and attending lectures, I had the privilege to briefly talk to attendees about my future plans. I concluded my PhD in December 2019 and will be moving to Indiana to work as a Premier Account Manager for Alta Genetics in February 2020. In this role, I will be working with progressive dairy producers in Indiana, Ohio and Florida, providing consulting services targeted on improving reproductive performance using a data-driven, decision-making process, and trainings provided to employees. Coincidentally, during the DCRC meeting, I was fortunate to talk to a few producers I will be working with, which was quite gratifying. I am positive my experiences with DCRC in 2019 and in previous years were vital in building my professional network, which ultimately helped me get this position.

I would like to thank all professionals who were involved in organizing the DCRC Annual Meeting, as well as the sponsors. This event would not be possible without these volunteers and sponsors. Also, I would like to express my sincere gratitude for being selected as a DCRC Scholar. I look forward to participating in the next DCRC Annual Meeting in Wisconsin!

Next DCRC webinar discusses heifer breeding strategies

Mark your calendar for the next Dairy Cattle Reproduction Council (DCRC) webinar – Reproductive Management Strategies to Optimize the Performance of Replacement Animals (“Estrategias de manejo reproductivo para optimizar la performance de animales de reemplazo”) for Dec. 10, at 2 p.m. Central time. Cornell University Associate Professor Julio Giordano will deliver this webinar in Spanish and discuss how reproductive programs that combine aggressive use of estrous detection and timed artificial insemination (TAI) – or all-TAI programs for first service – compare with predominantly estrous-detection programs in dairies with different estrous-detection efficiency. 

During the one-hour webinar, Giordano will address these key topics: 

• Primary drivers of success for heifer reproductive programs
• Effective ovulation-synchronization protocols to facilitate heifer TAI 
• Effect of estrous-detection efficiency on heifer reproductive performance

“Remarkable differences in reproductive performance may be observed among herds that implement the same reproductive management programs but have different estrous-detection efficiency,” said Giordano. “Implementation of all-TAI programs or combinations of AI at detected estrus with TAI to minimize days to first service can reduce time to pregnancy in heifers when compared with programs designed to prioritize AI at detected estrus. Nevertheless, differences for time to pregnancy are highly dependent on estrous-detection efficiency.”

Giordano received his Doctor of Veterinary Medicine degree from the Universidad Catolica de Cordoba, master’s degree from the University of Tennessee-Knoxville and doctorate degree from the University of Wisconsin-Madison. His research focuses on dairy cattle reproductive physiology, management and the implications of reproductive performance on dairy farm economics. Giordano’s research integrates basic and applied science to enhance the reproductive performance and productivity of cows. Through cow performance improvement, his program strives to improve the economic viability of dairy farms.

Save this date and time for the final 2019 DCRC webinar:

• Julio Giordano (presented in Spanish), Cornell University, presents “Reproductive Management Strategies to Optimize the Performance of Replacement Animals” (“Estrategias de Manejo Reproductivo para Optimizar el Desempeño de los Animales de Remplazo”) Dec. 10, at 2 p.m. Central time

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. 

• DCRC Webinar, Reproductive Management Strategies to Optimize the Performance of Replacement Animals (Estrategias de Manejo Reproductivo para Optimizar el Desempeno de los Animales de Remplazo) (presented in Spanish), December 10, at 2 p.m. Central time
• PDPW Managers Academy for Dairy Professionals, January 14-16, Corpus Christi, Texas
• Dairy Strong Conference, January 22-23, Madison, Wisconsin
• National Mastitis Council Annual Meeting, January 23-31, Orlando, Florida
• Pennsylvania Dairy Summit, February 5-6, State College, Pennsylvania
• National Cattlemen’s Beef Association, February 5-7, San Antonio, Texas
• World Ag Expo, February 11-13, Tulare, California
• Commodity Classic, February 27-29, San Antonio, Texas
• National Dairy Herd Information Association Annual Meeting, March 3-5, Savannah, Georgia
• Professional Dairy Producers of Wisconsin Business Conference, March 18-19, Madison, Wisconsin
• Central Plains Dairy Expo, March 24-26, Sioux Falls, South Dakota
• Dairy Calf and Heifer Association Annual Conference, April 7-9, Madison, Wisconsin
• National Mastitis Council Regional Meeting, May 5-8, Visalia, California
• Animal Agriculture Alliance Stakeholders Summit, May 7-8, Arlington, Virginia
• National Association of Animal Breeders Technical Conference on Artificial Insemination and Reproduction, September 16-18, Fontana, Wisconsin
• American Association of Bovine Practitioners Conference, September 24-26, Louisville, Kentucky
• Word Dairy Expo, September 29-October 3, Madison, Wisconsin
• Dairy Cattle Reproduction Council 2020 Annual Meeting, November 10-12, Madison, Wisconsin