Source: VIRGINIA POLYTECHNIC INSTITUTE submitted to NRP
IMPACT OF PRE-WEANING NUTRITION ON ENDOCRINE INDUCTION OF MAMMARY DEVELOPMENT IN DAIRY HEIFERS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1007788
Grant No.
2016-67015-24575
Cumulative Award Amt.
$500,000.00
Proposal No.
2015-06410
Multistate No.
(N/A)
Project Start Date
Jan 1, 2016
Project End Date
Dec 31, 2021
Grant Year
2016
Program Code
[A1231]- Animal Health and Production and Animal Products: Improved Nutritional Performance, Growth, and Lactation of Animals
Recipient Organization
VIRGINIA POLYTECHNIC INSTITUTE
(N/A)
BLACKSBURG,VA 24061
Performing Department
Dairy Science
Non Technical Summary
The ProblemAbout one-third of the U.S. dairy herd valued at ($5.4B) is replaced yearly. These replacement animals come from the female calves born to lactating cows on these farms. It has become widely appreciated that nutrition and management of animals in early life can dramatically affect future performance, longevity, and well-being of these animals. We recently confirmed that pre-weaning calf nutrition can dramatically affect growth and development of the mammary gland and especially the quantity of epithelial tissue in the developing gland. Because these rudimentary mammary ducts give rise to the mammary tissue that will ultimately synthesis and secrete milk, these tissue precursors are important. In fact, calves with low or modest nutrient intake in the pre-weaning period produce significantly less milk later in life compared with those with a higher nutrition program. It is not unreasonable to view this enhanced pre-weaning feeding as a 'Head Start' program for calves.Consequently, the first objective of our project is to learn the cellular and molecular factors that allow the improved mammary development in those calves better fed during the pre-weaning period. To address this objective we will randomly assign new born calves (n = 12) to a restricted (R) or enhanced (E) feeding regime. At weaning these animals will be sacrificed to provide tissues for analysis.We will measure the effects of these treatments on factors that correspond with mammary tissue growth. Measurements include: mammary tissue mass and composition [DNA, protein, lipid], mammary morphogenesis i.e. how the ductal elements actually develop [cellular stratification, development of myoepithelial cells], and quantitative multispectral imaging with immunocytochemistry. This last measure provides a way to measure the expression of proteins that we know impact development on a per cell basis. We will know what type of cells within the mammary gland is actually producing the protein and relatively how much. In the past most measures of protein expression required that the tissue sample be homogenized and expression compared relative to total tissue proteins. This imaging technique will give us very specific and novel information that relates protein expression to specific populations of defined cells in the developing mammary gland. Some of the proteins we will measure include estrogen and progesterone receptor, IGF-I receptor, incorporation of BrdU (relates to the rate of cell proliferation), and p63 (a marker of myoepithelial cells).A related hypothesis is that enhanced feeding alters myoepithelial cell development which modulates increased proliferation of epithelial cells and organization of mammary ductal structures. Our evaluation of myoepithelial cells in the bovine mammary gland is novel. Use of the p63 marker allows us determine the presence, location, and orientation of these cells in the developing tissue. In addition, mammary tissue collected will be cultured with graded concentrations of estradiol to measure acute gene expression responses to exposure to exogenous estrogen. This is a parallel to the experiment described below.A major hypothesis is that enhanced neonatal nutrition improves mammary development by increasing the responsiveness of mammary target cells to action of mammogenic hormones. We are focused on estrogen and signaling pathways known to have cross-talk with the estrogen receptor pathway, for example IGF-I. To test this hypothesis, calves (n = 24) will be assigned at birth to the two dietary treatments as described above. However, at weaning calves will be assigned to create the following treatment groups (n = 6/treatment): 1) calves fed R and given a placebo implant (R), 2) calves fed R and given an estradiol implant (R-E2), 3) calves fed E and given a placebo implant (E), and 4) calves fed E and given an estradiol implant (E-E2). Calves will be supplemented with estrogen for 2 weeks post-weaning, at which point all remaining animals will be harvested to assess the effects of estrogen within each diet on body and organ growth, particularly mammary gland growth. Measurements as described above will be applied to the tissues collected at sacrifice. In addition, collected tissue samples will be used to evaluate gene expression based on RNA sequence data. Combined with the appropriate bioinformatics analysis tools, this sequence data will provide a comprehensive evaluation of changes in expression of families of genes that regulate mammary growth and development and the impacts of diet and hormonal stimulation on expression of these genes.We expect the results of our project to provide important new information on the regulation of prepubertal bovine mammary development and to provide the impetus for nutritional and management tools to further improve 'Head Start' programs for dairy replacement heifers.
Animal Health Component
45%
Research Effort Categories
Basic
55%
Applied
45%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
3053410102030%
3023499103040%
3153999104030%
Knowledge Area
302 - Nutrient Utilization in Animals; 305 - Animal Physiological Processes; 315 - Animal Welfare/Well-Being and Protection;

Subject Of Investigation
3499 - Dairy cattle, general/other; 3999 - Animal research, general; 3410 - Dairy cattle, live animal;

Field Of Science
1040 - Molecular biology; 1030 - Cellular biology; 1020 - Physiology;
Goals / Objectives
Our long-term goal is to understand how enhanced neonatal nutrition in heifer calves influences future mammary development and function. More broadly we are interested in the impact of pre-weaning nutrition on general physiological growth and development, immunological function, health, and animal well-being. Think of this as 'Head Start' for Calves.Specific to our first objective we will determine cellular and molecular mechanisms that allow the marked increases in mammary ductal development in enhanced fed vs. control fed heifers we have observed. We are focused on estrogen and signaling pathways that cross-talk with the estrogen receptor pathway. This is because ovarian derived estrogen is the classic-core stimulator of mammary ductal development across essentially all mammals.A novel second objective is to determine if pre-weaning nutrition alters myoepithelial cell development which then acts to modulate increased proliferation of epithelial cells and development of appropriately organized mammary ductal structures. This objective comes from cancer and rodent studies that suggest myoepithelial cells (in addition to their well-recognized role in milk ejection in the mature lactating mammary gland) are also involved in regulation of mammary ductal growth and morphogenesis.Our third objective is to test our hypothesis that pre-weaning diet alters the capacity of the mammary epithelial cells to response to mammary growth promoting signals. We will specifically determine if calves fed an enhanced diet vs. control diet express differences in their capacity to respond to exogenous estradiol (placebo implant vs. estrogen containing implant) as well as acute in vitro tissue response (mammary explant culture) to graded concentrations of estradiol added to the culture medium. For these explant tissues we will determine gene expression responses using a systems biology approach via RNA sequence analysis.In tissues collected from calves, we will measure the effects of diet and estradiol stimulation on mammary growth (DNA, protein, lipid, tissue weight), morphogenesis (cellular stratification, development of myoepithelial cells), protein expression by cell type and structural classification (quantitative multispectral imaging and immunocytochemistry e.g. CD10, p63, estrogen receptor, progesterone receptor, IGF-I receptor, etc.), acute cell proliferation (incorporation of BrdU), and gene expression also using a systems biology approach.Moreover, the systems biology approach we will use to evaluate differences in gene expression differences in mammary tissue from control vs. accelerated fed calves and anticipated differential responses of these two groups of animals to mammogenic hormone stimulation (estradiol) offers unique opportunities to identify molecular, cellular, and biochemical pathways that control neonatal bovine mammary development and growth.These varied approaches will provide insight into how very early calf-hood nutrition acts to regulate subsequent mammary development, mammary function, and cow performance.
Project Methods
To evaluate the tissues we will collect from the animals in this project we will utilize a number of standard biochemical and compositional analysis techniques. Some of these tissues will come from animal experiments and other samples from tissues collected and cultured (in vitro). Both of these approaches offer advantages and disadvantages i.e. animal experiments are real world, all physiology systems involved, etc. The culture experiments offer greater experimental control but the absence of interactions with other physiological systems.Some of the specific measurements will include: biochemical measurement of DNA, protein, lipid in mammary tissue samples, morphogenesis analysis via quantitative morphometric techniques (cellular stratification, development of myoepithelial cells), protein expression by cell type and structural classification (quantitative multispectral imaging and immunocytochemistry e.g. CD10, p63, estrogen receptor, progesterone receptor, IGF-I receptor, etc.), acute cell proliferation (incorporation of BrdU), and gene expression using a RNA sequencing systems biology approach.Data analysis from a statistical standpoint will utilize tools and models available in the Statistical Analysis System (SAS) as well as specialized bioinformatics tools to evaluate effects of nutrition and hormone stimulation on gene expression and especially changes in families of related genes.

Progress 01/01/21 to 12/31/21

Outputs
Target Audience:Similar to thepast the primary target audience has been fellow researchers as well as p[roducers and industry professionals reached by prior publications and presentations. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?Please see earlier comments. What do you plan to do during the next reporting period to accomplish the goals?The primary goals of the project have been completed and the results presented and published in the scientific literature.

Impacts
What was accomplished under these goals? One measure of the success of research results from this project has been the very good acceptance of data frokm the project by other scientists. As of mid-December 2021 the four primary journal articles from the project have received 108 citations, according to data compiled by Research Gate. Other papers derived from the project i.e. Reviews and other related papers utilizing samples from our animals have captured and additional 49 citations. These data provide a reasonable measure of the impact the results for our project with colleagues in the scientific community. One additional experiment was also completed during the year. I anticipate results from this experiment will be included in a a graduate student MS thesis will be presented at scientific meeting in the following year.

Publications


    Progress 01/01/16 to 12/31/21

    Outputs
    Target Audience:Given the basic research focus of this project, our primary audience was fellow scientists and researchers interested in mammary development and the impacts of early preweaning nutrition on subsequent mammary development. As well as dairy nutrition professionals, especially those interested in calf and heifer health, nutrition, and well-being. I am pleased to report that data and results from our project have been very widely disseminated and based on subsequent citations of the papers published from the project very widely read. In addition, Dr. Adam Geiger (his Ph.D. studies were centered on this project) has gone to a successful career in the dairy industry with an emphasis on calf health and the importance of preweaning and early postweaning nutrition on mammary development and subsequent health and lactation. Our project produced 7 referred full scientific papers, most published in the Journal of Dairy Science. As of late 2021, these papers hadreceived a total of 114 citations in publications by other scientists from around the world. Moreover, other reviews which included discussions of these results have received an additional 49 citations. These metrics provide a measure of the success of our efforts and interest in results from this research. In addition, to the published papers, there were at least 15 presentations of results from the project at various scientific meeting and industry conferences during the funding period. These efforts were also central in efforts to disseminate our results. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?As outlined previously, Dr. Adam Geiger was the primary graduate student for this project. This training and his passion for this topic lead to his successful career as a dairy industry professional focused on teaching other dairy industry professionals as well as producers about the significance of early calfhood nutrition on the subsequent success of these calves to become quality replacement heifers in dairy herds around the country. How have the results been disseminated to communities of interest?Please see the early section regarding acceptance of our results by other researchers around the world. Given a majority of scientific papers receive only limited numbers of citations, the success of this project in that regard is very clear from the high citation rates. Indeed, only one year after its initial publication, the first primary paper from the project made it on to Journal of Dairy Science's 100 most highly cited papers. The quote for the letter from the Journal includes the following: "On behalf of ADSA Board of Directors and the editors of the Journal of Dairy Science (JDS), would likie to thank you for your contributions to the high Impact Factor of the journal. Acccording to the Web of Science, yours is among the 100 most highly cited papers published in JDS since the beginning of 2014. This metric provides another measure of the success we had in successfully disseminating our results of our communities of interest. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

    Impacts
    What was accomplished under these goals? Our studies established the significance of enhanced preweaning nutrition on subsequent mammary development. Indeed enhanced fed calves had 5.2-fold more mammary mass that restricted fed calves. Improved epithelial cell growth in the developing mammary gland was linked with altered responses of steriod receptors in these tissues as well as a myriad of molecular alterations determined by companion genetic expression measurements. The bioinformatics analysis of the transcriptomes from mammary parenchyal and mammary fat pad tissues from restricted fed and enhanced fed calves (published in BMC Genomics), showed dramatic and complex alterations in the activities of multple genes. Specifically, comparing enhanced vs restricted fed calves 1591 genes (895 upregulated, 666 downregulated), and 970 genes (506 upregulated, 464 downregulated) were differentially expressed in parenchymal mammary tissue compared with the mammary fat pad. These data highlight greater proliferation and differentiation activity in both the mammary parenchymal tissue and the mammary fat pad from enhanced fed calves compared with restricted fed animals. The parenchymal tissue from enhanced fed calves desplayed transcriptional signs of greater organ development, increased ductal growth and branching, andchanges in trancriptional activity linked with improved blood vessel creation. These changes were likely mediated by intracellular cascades correspondly linked to hormonal and growth factor signaling. In addition, thesedata also indicated strong communication between the mammary fat pad and the parenchymal tissue. Regardless, of specific mechanisms these experiments provide compelling evidence that early pre and post weaning feeding changes can offer producers practical opportunies to 'program' their calf feeding methods to optomize both calf health and positively impact subsequent heifer development as well as future lactation performance.

    Publications


      Progress 01/01/20 to 12/31/20

      Outputs
      Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Dr. Adam Geiger is now a well respected industry professional in the area of calf nutrition and health. Dr. Ben Enger is now an assistant professor at Ohio State, he worked at bit related to this project and was a graduate colleague of Dr. Geiger in my laboratory (Akers). How have the results been disseminated to communities of interest?Dr. Geiger has continued to promote the lessons we learned from this project in his ongoing talks and training of producers and other industry personel, specifically the benefits of enhanced early nutrition on subsequent mammary development and function. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

      Impacts
      What was accomplished under these goals? We had an extensive series of scientific publications and related talks and presentations. Please review prior listings. A final animal trial is currently underway but there will be nothing to report until next year. An additional paper is in draft from and we anticipate submission for publication in 2021.

      Publications


        Progress 01/01/19 to 12/31/19

        Outputs
        Target Audience:The target audience has and continues to be other researchers and scientists. As well as some lay audiences especially via the continuing work of Dr. Adam Geiger who completed his Ph.D. as a consequence of this project. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?Please see above, i.e. multiple scientific publications and presentations. What do you plan to do during the next reporting period to accomplish the goals?Complete some final publications goals.

        Impacts
        What was accomplished under these goals? I am pleased to report that with the exception of the an originally longer-term feeding experiment that all our goals have been completed. As indicated in the prior report, logistics at the dairy center made these particular goal impossible to complete. However, with our work and that of research colleagues the importance and relevance of early prepubertal feeding of dairy calves to support subsequent mammary growth and development has been firmly estabilished. The project is winding down. It is also significant that we made excellent use of the samples collected from animals used in this project. Specifically, to date we have published 11 full scientific articles (including 1 paper, published this year) as well as 18 paper presentations/abstracts at professional meetings. I think this is an exceptionally good scientific productivity record from this project. Lastly, I anticipate one additional paper from this project will be submitted this coming year.

        Publications

        • Type: Journal Articles Status: Published Year Published: 2019 Citation: Owens, C. E., A. J. Geiger, R. M. Akers, and R. R. Cockrum. 2019. Varying dietary protein and fat elicits differential transcriptomic expression within stress response pathways in pre-weaned Holstein heifers. J. Dairy Sci. 102: 1630-1641.


        Progress 01/01/18 to 12/31/18

        Outputs
        Target Audience:For this period our target audience continues to be the scientific community and more broadly dairy producers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Dr. Adam Geiger successfully completed his Ph.D. and this project was the primary basis of his dissertation project. We have published a extensively based on the project including a number of cooperative projects that made use of the samples from the animals envolved. Dr. Geiger and I are currently working on an additional primary manuscript we expect to be submitted this summer (2019). There may also be additional publications in cooperation with Dr. Juan Loor at the University of Illinois. Several undergraduate students also gained valuable experience working on the project. How have the results been disseminated to communities of interest?Please see the publications listing. Not included are some project related talks given to dairy interest groups and Dr. Gieger has used the results from the project extensively in his current professonal development i.e. dairy industry professional. What do you plan to do during the next reporting period to accomplish the goals?The project is largely completed. We will continue to finish planned publications and participate in talks that may arise. I am quite happy with the out come from the project. Thus far 24 conference abstract publications and talks and 12 refereed full scientific journal articles. Several of these came from shared tissues and samples from the project. This I think strongly supports the utility of the design of our study and its relevance to other scientists.

        Impacts
        What was accomplished under these goals? Please refer to comments provided below. All objections with the exception of our original plan for some longer-term feeding were successfully completed. Logistics at the dairy center made specific plan impossible to complete. Regardless, the publication and presentation evidence demonstrations excellent progress. The relevance of early prepubertal feeding of prepubertal calves to support mammary growth and development is firmly established.

        Publications

        • Type: Journal Articles Status: Published Year Published: 2017 Citation: Akers, R. M., 2017. Plasticity of mammary development in the prepubertal bovine mammary gland. J. Animal Sci. 95: 5653-5663.
        • Type: Journal Articles Status: Published Year Published: 2018 Citation: Vailati-Riboni, M. V., R. E. Bucktrout, S. Zhan, A. Geiger, J. C. McCann, R. M. Akers and J. J. Loor. 2018. Higher plane of nutrition pre-weaning enhances Holstein calf mammary gland development through alterations in the parenchyma and fat pad transcriptome. BMC Genomics 19:900 https://doi.org/10.1186/s12864-018-5303-8.
        • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: " Owens, C. E., A. J. Geiger, C. M. Parsons, R. M. Akers and R. R. Cockrum. 2018. Pre-weaned dietary energy composition influences Proteobacteria abundance in post-weaned Holstein calves. Proc. World Congress on Genetics Applied to Livestock Production.
        • Type: Journal Articles Status: Published Year Published: 2019 Citation: Owens, C. E., A. J. Geiger, R. M. Akers, and R. R. Cockrum. 2019. Varying dietary protein and fat elicits differential transcriptomic expression within stress response pathways in pre-weaned Holstein heifers. J. Dairy Sci. 102: 1630-1641.
        • Type: Journal Articles Status: Published Year Published: 2018 Citation: Parsons, C. L. M., H. L. M. Tucker, K. M. Daniels and R. M. Akers. 2018. Technical Note: p40 Antibody as a replacement for p63 antibody in bovine mammary immunohistochemistry. J. Dairy Sci. 101: 7614-7617.
        • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Riboni, M. V., V. Palombo, A. J. Geiger, R. M. Akers and J. J. Loor. Level of estrogen in mammary parenchyma explants from weaned Holstein heifer calves increases growth and proliferation through transcriptional mechanisms as evaluated via RNA-sequencing. J. Dairy Sci. 101: (Suppl. 2, Abstract T165, Page 273).
        • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Geiger, A. J., C. L. M. Parsons4 and R. M. Akers. 2018. The impact of pre-weaning nutrition on the myoepithelial cell population within the immature bovine mammary gland. J. Dairy Sci. 101: (Suppl. 2, Abstract 416, Page 380).
        • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Granger, P. D., R. M. Akers, C. L. M. Parsons, A. J. Geiger, B. A. Corl and K. M. Daniels. 2018. Effects of in vivo estradiol administration on abundance and localization of yes-associated protein, an evolutionarily conserved molecule implicated in organ size regulation, in prepubertal bovine mammary tissue. J. Dairy Sci. 101: (Suppl. 2, Abstract T152, Page 269).


        Progress 01/01/17 to 12/31/17

        Outputs
        Target Audience:Scientific publications and popular press articles published and several talks presented. Audience includes other scientists, graduate students, industry professionals, and some dairy producers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Dr. Adam Geiger, received his Ph.D. -- currently employed in the Dairy Indusry as a calf and nutrition expert. His training in all of the aspects of this project prepared him for this position. Further analysis and publications are on going. How have the results been disseminated to communities of interest?Scientific publications and associated talks. As well as multiple popular press articles. What do you plan to do during the next reporting period to accomplish the goals?See above, continued scholarship.

        Impacts
        What was accomplished under these goals? We demonstrated that enhanced feeding of prepubertal calves did indeed enhance the capacity of the mammary tissue to respond to mammogenic stimulation. We are currently working on publications describing changes in specific genes associated with these endocrine linked responses. In particular, terminal ductal structures were especially sensitive to both dietary effects and response to stimulation with estradiol. That is enhance feeding correspondingly enhance the capacity of the these terminal structures to respond. Changes in estrogen receptor expression at the protein level within receptor positive cells were increased by enhanced feeding. Indeed, the publication describing these effects was selected as an Editor's Choice Paper and received extra press in the Journal of Dairy Science.

        Publications

        • Type: Journal Articles Status: Published Year Published: 2017 Citation: Akers, R. M. 2017. Mammary development and lactation  A review. J. Dairy Sci. 100:10332-10352. Geiger, A. J., C. L. M. Parsons, and R. M. Akers. 2017. Feeding an enhanced diet to Holstein heifers during the pre-weaning period impacts steroid receptor expression and increases cellular proliferation. J. Dairy Sci. 100: 8534-8543. Wilson, M. L., S. R. McCoski, A. J. Geiger, R. M. Akers, S. E. Johnson and A. D. Ealy. 2017. Postnatal nutrition impacts reproductive tract and endometrial gland development in dairy calves. J. Dairy Sci. 100:3243-3256.
        • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Owens, C. E., A. J. Geiger, R. M. Akers and R. R. Cockrum. 2017. Growth and metabolic pathways are impacted by milk replacer dietary energy in pre-weaned heifers. J. Dairy Sci. 100: (Suppl. 2, Abstract 34, Page 132-133). Owens, C., E. Bart, A. J. Geiger, C. L. M. Parsons, R. M. Akers, R. R. Cockrum. 2017. Increase in dietary energy of milk replacer increases rumen microbiome diversity in heifer calves. Plant and Animal Genome Conference XXIV, San Diego, CA., January 14-17 2017, P1062. Zhan, S., A. J. Geiger, J. C. McCann, M. Vailati-Roboni, R. M. Akers and J. J. Loor. 2017. A higher plane of nutrition in pre-weaned Holstein heifer calves alters transcriptomic profiles in mammary parenchyma and fat pad. J. Dairy Sci. 100: (Suppl. 2, Abstract T155, Page 284). Zhan, S., A. J. Geiger, J. C. McCann, M. Vailati-Roboni, R. M. Akers and J. J. Loor. 2017. Impact of higher-plane of nutrition and post-weaning exogenous estrogen on transcriptome profiles in mammary parenchyma and fat pad of Holstein heifer calves. J. Dairy Sci. 100: (Suppl. 2, Abstract T156, Page 284-285). Owens, C. E., A. J. Geiger, R. M. Akers and R. R. Cockrum. 2017. Growth and metabolic pathways are impacted by milk replacer dietary energy in pre-weaned heifers. J. Dairy Sci. 100: (Suppl. 2, Abstract 34, Page 132-133). Owens, C., E. Bart, A. J. Geiger, C. L. M. Parsons, R. M. Akers, R. R. Cockrum. 2017. Increase in dietary energy of milk replacer increases rumen microbiome diversity in heifer calves. Plant and Animal Genome Conference XXIV, San Diego, CA., January 14-17 2017, P1062. Zhan, S., A. J. Geiger, J. C. McCann, M. Vailati-Roboni, R. M. Akers and J. J. Loor. 2017. A higher plane of nutrition in pre-weaned Holstein heifer calves alters transcriptomic profiles in mammary parenchyma and fat pad. J. Dairy Sci. 100: (Suppl. 2, Abstract T155, Page 284). Zhan, S., A. J. Geiger, J. C. McCann, M. Vailati-Roboni, R. M. Akers and J. J. Loor. 2017. Impact of higher-plane of nutrition and post-weaning exogenous estrogen on transcriptome profiles in mammary parenchyma and fat pad of Holstein heifer calves. J. Dairy Sci. 100: (Suppl. 2, Abstract T156, Page 284-285).
        • Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Akers, R. M. 2017. Plasticity of mammary development in the prepubertal bovine mammary gland. J. Anim. Sci. (in press).
        • Type: Book Chapters Status: Published Year Published: 2017 Citation: Akers, R. M. 2017. Mammary Development in Calves and Heifers in Large Herd Dairy Management, 3rd Edition, The American Dairy Science Association. Section 9, Chapter 59, 815-827.


        Progress 01/01/16 to 12/31/16

        Outputs
        Target Audience:During the current cycle we reported results from our project at multiple sessions at the Annual Meeting of the American Dairy Science Association Meeting. Dr. Adam Geiger, the primary Ph.D. student involved in the project was the 2nd place award winner in the Ph.D. Oral presentation contest at the annual meeting. We also presented somefindings at an invited meeting -- Mammary Development in Calves and Heifers as part of the Large Dairy Herd Management Conference, Hilton Chicago/Oak Brook Hills Resort and Conference Center, Oak Brook, IL. We also prepared a book chapter for a publication that will appear as a consequence of the conference. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Because of interest in the project by colleagues, tissues collected at the time of slaugher have been used for multiple studies protions of which have been and are being used to support undergraduate research projects for 4-5 undergraduate students, 3-4 additional MS students and one postdoctoral fellow.Some examples include the full papers and conference papers pasted below. I think this is really excellent use of these resources and a testiment to the interest inour project formultiple organs not just mammary gland. Beaudry, K., C. L. M. Parsons, S. E. Ellis and R. M. Akers. 2016. Changes in mammary tissue populations of eosinophils, mast cells, and macrophages during prepubertal mammary growth in the bovine. J. Dairy Sci. 99:796-804. MacGhee, M. E., S. R. McCoski, A. J. Geiger, R. M. Akers, S. E. Johnson and A. D. Ealy. 2016. Postnatal nutrition impacts reproductive tract and endometrial gland development in dairy calves. J. Dairy Sci. (submitted). Holloway, T. L., A. J. Geiger1, J. Malkus, A. D. Ealy, R. R. Cockrum and R. M. Akers. 2015. Exogenous estradiol decreases relative endometrial gene expression for ERα and ERβ in pre-pubertal dairy heifers. J. Dairy Sci. 98: (Suppl. 2, Abstract T223, page 391). MacGhee, M. E., S. R. McColski, A. J. Geiger, E. A. Horton, R. M. Akers and A. D. Ealy. 2015. The role of early postnatal nutrition and estrogen administration in uterine gland development in Holstein Dairy Calves. Soc. Study Reproduction Program 48th Annual Meeting, Page 108, Abstract. 269. Lu, Y., J. S. Bradley, S. R. McCoski, J. M. Gonzalez, A. J. Geiger1, R. M. Akers, A. D. Ealy and S. E. Johnson. 2016. Caloric restriction reduces protein accretion in skeletal muscle by attenuating IGF-I signaling in young calves. J. Dairy Sci. 99: (Suppl 2, Abstract T229, Page 694). Lu, Y., J. S. Bradley, S. R. McCoski, A. J. Geiger1, R. M. Akers, A. D. Ealy and S. E. Johnson. Muscle fiber hypertrophy is associated with increased expression of key transcriptional and epigenome regulatory genes. J. Dairy Sci. 98: (Suppl. 2, Abstract W218, Page 694 How have the results been disseminated to communities of interest?See publications and presentations listings. What do you plan to do during the next reporting period to accomplish the goals?We are continuing with additional laboratory analysis and especially detailed gene expression analysis with Dr. Juan Loor at the Univeristy of IL. As indicated above we expect multiple additional presentations and publications. As a specific example, I will present some of these results at an invited presentation Title: Plasticity of Mammary Development in the Prepubertal Bovine Mammary Gland Where: International Lactation Symposium, Baltimore MD, July 2017 Includes Invited Review Paper

        Impacts
        What was accomplished under these goals? We have demonstrated emphaticallythat changes in prepubertal feeding can dramatically mammary development i.e. 7.3-fold greater development of mammary parenchymal tissue mass in well fed calves. We have found that these differences in tissue development are indeed accompanied by dramatic differences in the expression estrogen receptors in the developing mammary ductal system (reduce in calves with a lower feeding level), this is in accompaniment with a decreased rate of epithelial cell proliferation. Differences were especially pronounced in more distal regions of the developing ductal system. We also noted that use of DEXA scanning was useful to estimate difference in the fat content of the udder in calves but not for demonstrating differences in parenchymal development. Our continuing analysis is focused on gene expression differences induced by dietary manipulation as well as effects of estrogen treatment. We have also noted that diet manipulation impacts myoepithelial cell development and this may be important in control of mammary growth and development. We anticipate 4-5 additional full papers will be submitted/published in 2017/2018. ?

        Publications

        • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Geiger, A. J., C. L. M. Parsons and R. M. Akers. 2016. Enhanced pre-weaning nutrition increases mammary development without negatively affecting tissue composition in Holstein heifer calves. J. Dairy Sci. 99: (Suppl. 2, Abstract 734, Page 345).
        • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Geiger, A. J., C. L. M. Parsons and R. M. Akers. 2016. Efficacy of dual x-ray absorptiometry as a means to measure mammary gland development in dairy heifer calves. J. Dairy Sci. 99: (Suppl. 2, Abstract 869, Page 410).
        • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Geiger, A. J., C. L. M. Parsons4 and R. M. Akers. 2016. Pre-weaning diet and exogenous estrogen alter mammary epithelial cell proliferation and progesterone and estrogen receptor expression. J. Dairy Sci. 99: (Suppl. 2, Abstract 781, Page 368).
        • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Owens, C., A. J. Geiger, C. L. M. Parsons4, R. M. Akers and R. Cockrum. 2016. Sire performance and reproductive breeding values are associated with feed efficiency and growth in dairy heifers. J. Dairy Sci. 99: (Suppl. 2, Abstract 744, Page 350).
        • Type: Journal Articles Status: Published Year Published: 2016 Citation: Geiger, A. J., C. L. Parsons, R. E. James and R. M. Akers. 2016. Growth, intake, and health of Holstein heifer calves fed an enhanced pre-weaning diet with or without exogenous estrogen immediately post-weaning. J. Dairy Sci. 99: 3995-4004.
        • Type: Journal Articles Status: Published Year Published: 2016 Citation: Geiger, A. J., C. L. Parsons, and R. M. Akers. 2016. Feeding a higher plane of nutrition and providing exogenous estrogen positively impacts mammary gland development in Holstein heifer calves. J. Dairy Sci. 99: 7642-7653.