METHODS TO INCREASE REPRODUCTIVE EFFICIENCY IN CATTLE

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1013311
• Multistate No.: NC-1201
• Project Start Date: Oct 1, 2017
• Project End Date: Jun 30, 2019
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIV OF WISCONSIN
21 N PARK ST STE 6401
MADISON,WI 53715-1218

Performing Department
Dairy Science

Non Technical Summary
Progesterone is the most biologically active progestagen in cattle. The main idea underlying this proposal is that reproduction in high producing dairy cows is impaired by inadequate progesterone concentrations due to hepatic steroid metabolism driven by high feed intake required for high milk production. Thus, the Specific Aim of this work is to manipulate progesterone to improve fertility to timed AI in dairy cows. In Experiment 1 we will use the PGF2α-induced decrease in P4 of the early corpus luteum to increase ovulatory response to GnRH to increase fertility to a timed AI protocol. In Experiment 2, we will delay insertion of a P4 device by 1 d during a timed AI protocol to increase fertility by increasing ovulatory response to GnRH. In Experiment 3, we will increase P4 before ovulation during growth of the ovulatory follicle to try to reduce pregnancy loss after timed AI. In Experiment 4, we will manipulate P4 after timed AI to affect embryo growth and impact maternal recognition of pregnancy and/or pregnancy loss. Results from these experiments may have an immediate impact on fertility of cows in Wisconsin and will clarify the role of P4 during follicular growth before and embryo growth after ovulation.Generation of new knowledge from on-farm research that brings the University of Wisconsin-Madison together with farmers and veterinarians and dissemination of that knowledge to the larger dairy industry provides the structure from which positive change in the dairy industry can occur. New knowledge gained from the experiments in this proposal and the dissemination of this information to the dairy industry draws from the fundamental basis upon which UW Extension, the Wisconsin Idea, and the Land Grant University System were founded: to enhance the application of useful and practical information beyond the university campus through cooperative Extension efforts with states and local communities.

Animal Health Component

60%

Research Effort Categories

Basic

40%

Applied

60%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
301	3410	1020	100%

Knowledge Area
301 - Reproductive Performance of Animals;

Subject Of Investigation
3410 - Dairy cattle, live animal;

Field Of Science
1020 - Physiology;

Keywords

dairy cow

reproduction

Goals / Objectives
Increase the efficiency and predictability of sustainable reproductive technologies and management programs for cattle. Evaluate mechanisms that regulate reproductive processes impacting production efficiency in cattle.

Project Methods
On-farm implementation of reproductive management strategies should be based on nonbiased data from well-designed field research trials. Existing technologies and new management strategies and technologies need to be evaluated before recommendations can be formulated and implemented at the farm level. The main idea underlying this proposal is that reproduction in high producing dairy cows is impaired by inadequate progesterone concentrations due to hepatic steroid metabolism driven by high feed intake required for high milk production. Thus, the Specific Aim of this proposal is to manipulate progesterone to improve fertility to timed AI in dairy cows. In Experiment 1, we will use the PGF2α-induced decrease in progesterone of the early corpus luteum to increase ovulatory response to GnRH to increase fertility to a timed AI protocol. In Experiment 2, we will delay insertion of a progesterone device by 1 d during a timed AI protocol to increase fertility by increasing ovulatory response to GnRH. In Experiment 3, we will increase progesterone before ovulation during growth of the ovulatory follicle to try to reduce pregnancy loss after timed AI. In Experiment 4, we will manipulate progesterone after timed AI to affect embryo growth and impact maternal recognition of pregnancy and/or pregnancy loss.

Progress 10/01/17 to 06/30/19

Outputs
Target Audience:Target audiences for results from this project include: dairy farmers, AI technicians, veterinarians, and scientists. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Multiple veterinary workshops were held to update veterinarians on these latest research results. How have the results been disseminated to communities of interest?Dissemination of these results has been accomplished through peer reviewed publications (American Dairy Science Association and Journal of Dairy Science), peer reviewed abstracts, conference proceedings, extension meetings, and lay press articles. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Progesterone (P4) is the most biologically active progestogen in cattle and is primarily produced and secreted by the corpus luteum (CL) during the estrous cycle and the placenta during pregnancy. Reproduction in high producing dairy cows is impaired by inadequate progesterone concentrations due to hepatic steroid metabolism driven by high feed intake required for high milk production. Reproduction in nulliparous dairy heifers receiving an IVF embryo may also be affected by treatment with exogenous P4. Our objective was to assess the effect of treatment with human chorionic gonadotropin (hCG) 7 d after artificial insemination (AI) or at the time of in vitro-fertilized (IVF) embryo transfer on reproductive outcomes, including progesterone (P4), interferon-tau stimulated gene 15 (ISG15), pregnancy-specific protein B (PSPB), and pregnancies per AI (P/AI) or pregnancies per embryo transfer (P/ET), in nulliparous Holstein heifers. Two studies were conducted to assess the effect of manipulating P4 before AI (lactating dairy cows) or after AI or IVF embryo transfer (nulliparous heifers). Submission of lactating dairy cows to an Ovsynch protocol that included a second PGF treatment to induce complete luteal regression in a low P4 environment increased the incidence of double ovulation at AI, twin pregnancies, PSPB concentrations, and relative expression of ISG15 at 18 and 20 d after TAI. Treatment of nulliparous dairy heifers with 2,000 IU hCG on d 7 of the estrous cycle increased P4 concentrations but did not affect P/AI or P/ET 32 d after estrus or ovulation but decreased pregnancy loss only for heifers receiving IVF embryos.

Publications

Progress 10/01/17 to 09/30/18

Outputs
Target Audience:The target audiences are: dairy farmers, the AI industry, nutritionists, consultants, and veterinarians. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Angela M. Niles, June 2016 to August 2018. M.S. Thesis: "Manipulation of progesterone to improve fertility of Holstein dairy heifers after AI or IVF embryo transfer." Treatment with 2,000 IU hCG on d 7 of the estrous cycle increased progesterone concentrations but did not affect P/AI or P/ET 32 d after estrus or ovulation in in Holstein dairy heifers and decreased pregnancy loss only for heifers receiving IVF embryos. Current position: Reproductive Consultant, Genex, Twin Falls, ID. How have the results been disseminated to communities of interest?Results from this project have been disseminated to dairy farmers, the AI industry, nutritionists, consultants, and veterinarians through my statewide, regional, national, and international extension program. In 2018, I gave 17 presentations to international audiences in 7 different countries in 2018 with a total of 1,485 attendees; I gave 17 presentations at regional and national meetings in 8 different states in 2018 with a total of 844 attendees; and I gave23 presentations in Wisconsin in 2018 with a total of 706 attendees. What do you plan to do during the next reporting period to accomplish the goals?Pregnancy loss represents a substantial economic cost for dairy farms due to critical delays in time to pregnancy and decreased offspring and, among domestic livestock species, lactating dairy cows experience relatively high rates of pregnancy loss after establishing a viable pregnancy. My objective going forward is tounderstand the underlying mechanisms causing pregnancy loss and to develop strategies to decrease pregnancy loss in lactating dairy cows.

Impacts
What was accomplished under these goals? Progesterone (P4) is the most biologically active progestogen in cattle and is primarily produced and secreted by the corpus luteum (CL) during the estrous cycle and the placenta during pregnancy. Reproduction in high producing dairy cows is impaired by inadequate progesterone concentrations due to hepatic steroid metabolism driven by high feed intake required for high milk production. Reproduction in nulliparous dairy heifers receiving an IVF embryo may also be affected by treatment with exogenous P4. Our work included: Two studies were conducted to assess the effect of manipulating P4 before AI (lactating dairy cows) or after AI or IVF embryo transfer (nulliparous heifers). Submission of lactating dairy cows to an Ovsynch protocol that included a second PGF treatment to induce complete luteal regression in a low P4 environment increased the incidence of double ovulation at AI, twin pregnancies, PSPB concentrations, and relative expression of ISG15 at 18 and 20 d after TAI. Treatment of nulliparous dairy heifers with 2,000 IU hCG on d 7 of the estrous cycle increased P4 concentrations but did not affect P/AI or P/ET 32 d after estrus or ovulation but decreased pregnancy loss only for heifers receiving IVF embryos.

Publications

• Type: Journal Articles Status: Published Year Published: 2018 Citation: Barletta, R. V., P. D. Carvalho, V. G. Santos, L. F. Mello, C. E. Consentini, A. S. Netto, and P. M. Fricke. 2018. Effect of dose and timing of prostaglandin F2 alpha treatments during a Resynch protocol on luteal regression and fertility in lactating Holstein cows. J. Dairy Sci. 101:1730⿿1736.
• Type: Journal Articles Status: Accepted Year Published: 2019 Citation: Niles, A. M., H. P Fricke, P. D. Carvalho, M. C. Wiltbank, L. L. Hernandez, and P. M. Fricke. 2019. Effect of treatment with human chorionic gonadotropin 7 days after artificial insemination or at the time of embryo transfer on reproductive outcomes in nulliparous Holstein heifers. J. Dairy Sci. 102:(accepted).