Source: TEXAS A&M UNIVERSITY submitted to NRP
PRENATAL STRESS MODULATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS AND TELOMERE LENGTH
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1019395
Grant No.
2019-67015-29573
Cumulative Award Amt.
$251,000.00
Proposal No.
2018-07136
Multistate No.
(N/A)
Project Start Date
Jun 1, 2019
Project End Date
May 31, 2023
Grant Year
2019
Program Code
[A1251]- Animal Health and Production and Animal Products: Animal Well-Being
Recipient Organization
TEXAS A&M UNIVERSITY
750 AGRONOMY RD STE 2701
COLLEGE STATION,TX 77843-0001
Performing Department
Animal Science
Non Technical Summary
This project will study the potentially enduring effect of prenatal stress in order to develop sustainable solutions to improve the health and well-being and productivity of neonatal, growing cattle. The nature of one's life is shaped by the interaction of genetic and environmental factors. Stressful stimuli exacerbate health issues and reduce productivity of livestock by altering expression of stress and immune response genes. Stress shortens the length of human telomeres, the protective ends of chromosomes that maintain genetic integrity during DNA replication. Genetic and epigenetic mechanisms mediate neuroendocrine responses to environmental, managerial, and pathogenic stressors. Prenatal transportation stress of bull calves differentially methylates DNA (i.e., a chemical modification that alters expression) of genes related to behavior, stress response, and immunity. These modifications are set early in life and may be altered by stress and thus influence gene expression later in life. We propose to use the bovine prenatal stress model to test the concept that stress promotes attrition of telomeres (the protectors of chromosomal DNA). Our overarching hypothesis is that prenatal stress accentuates the negative effects of glucocorticoids and cytokines on telomeres and tissue specific expression of neuroendocrine factors regulating temperament and stress responsiveness. Prenatally stressed calves produced by stressing their mothers multiple times during gestation will be used in our bovine model for prenatal stress. This project will investigate the impact of prenatal stress on targeted neuroendocrine signaling systems and telomere length. Prenatally Stressed and Control calves will be compared in male and female calves at 28 days of age with regard to production of stress-related hormones and the length of telomeres in white blood cells. This research will identify new pathways to target with therapeutics or novel management strategies. There is a clear need for development of sensitive and accurate quantitative early biomarkers (i.e., hormones, methylation patterns or telomere length) of genetic susceptibility or resilience to stress. The proposed project will contribute to development of sustainable solutions to improve the health, well-being and overall productivity of neonatal and growing animals.
Animal Health Component
10%
Research Effort Categories
Basic
75%
Applied
10%
Developmental
15%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
31533101020100%
Knowledge Area
315 - Animal Welfare/Well-Being and Protection;

Subject Of Investigation
3310 - Beef cattle, live animal;

Field Of Science
1020 - Physiology;
Goals / Objectives
The long-term goal of this project is to enhance health, well-being and productivity of livestock by alleviation of the adverse effects of stress. The short-term goal is to gain fundamental knowledge of the relationship of stress with telomere homeostasis and epigenetic control of key stress-responsive neuroendocrine genes in beef cattle. Adverse early life experiences exert long-term negative consequences on health and well-being. Both prenatal stress and early life adversity are linked to: 1) epigenetic changes in nervous, immune, and endocrine systems; and, 2) decreased white blood cell telomere length in human neonates. We propose to use our bovine model of prenatal stress to determine its impact on white blood cell telomere length and DNA methylation in 28-day-old heifers and bulls. We will identify inter-relationships of neuroendocrine function, telomere length, and health and well-being in calves by pursuit of the following specific objectives:Objective 1A: Evaluate the effects of prenatal stress on white blood cell telomere length of neonatal purebred Brahman calves (28-day-old bulls and heifers) born in 2012.Objective 1B: Evaluate the effects of prenatal stress on white blood cell telomere length and DNA methylation of neonatal purebred Brahman calves (28-day-old bulls and heifers) to be born in 2019.
Project Methods
Objective 1A: Evaluate the effects of prenatal stress on white blood cell telomere length of neonatal purebred Brahman calves (28-day-old bulls and heifers) born in 2012.A prior prenatal stress project provided archived blood and DNA samples for the current project. In brief, during the year 2011, 96 pregnant Brahman cows in the research herd at the Texas A&M AgriLife Research Center in Overton, TX were randomly assigned to treatment or control groups within temperament classifications. The treatment group was transported by trailer on 5 occasions (2 h duration for each trip) at 20-day intervals between 60 to 140 days of gestation as an imposed prenatal stressor on their calves (stressed during latter part of 1st trimester and early part of 2nd trimester of pregnancy). Duplicate white blood cell aliquots were obtained from all calves (41 prenatal stress and 44 control) at 0 and 28 days of age. Objective 1A of this project will determine potential adverse effects of prenatal stress on telomere length by extraction of DNA from the archived samples to contrast telomere length of the prenatally stressed and control calves of both sexes at 0 and 28 days of age. The observed telomere length (determined by quantitative polymerase chain reaction) and Southern blot methods will be correlated with concentration of cortisol in the blood samples used to isolate the white blood cells to assess a potential linkage with telomere length in both Control and prenatally stressed male and female calves.Objective 1B: Evaluate the effects of prenatal stress on white blood cell telomere length and DNA methylation of neonatal purebred Brahman calves (28-day-old bulls and heifers) to be born in 2019.In the year 2018 we started the process to establish a new generation of prenatally stressed and control calves to be born in the year 2019 for study in this new project. This was done to test the hypothesis that prenatal stress alters telomere length, DNA methylation, and postnatal neuroendocrine control of stress responsiveness in cattle. In brief, from May 7 to June 30, 2018, 95 cows in the purebred Brahman herd at the Texas A&M AgriLife Research Center in Overton, TX were mated to the same bull by artificial insemination (i.e., a single-sire mating to reduce genetic variation due to multiple sires). Pregnant cows were identified as pregnant by rectal palpation 45 day after their last recorded breeding date. At that time, each pregnant cow was assigned to either the prenatal stress group or the control group based on age, parity, and temperament (transport procedure described below). Dam temperament was balanced between the 2 groups using each cow's pen score, exit velocity, and temperament score at weaning. The prenatal stressor consisted of 5 transportation events at 60, 80, 100, 120, and 140 ± 5 days of gestation. The transportation events took place from mid-Summer 2018 to early Fall 2018. Pregnant cows were transported in the same 3-section trailer (2.4 x 7.3 m) that was towed by a ¾ ton truck on smooth highways for a total of 2 hours at an average speed of 50 mph. This treatment was modeled after our previous studies that resulted in: 1) elevated body temperature, cortisol concentration, and glucose concentration in transported pregnant Brahman cows. From these cows, 32 calves will be studied in 2019 for the new project for Objective 1B (n=16 prenatal stress, 8 male and 8 female; and n=16 control, 8 male and 8 female). At weekly intervals starting in late March 2019, jugular blood samples will be obtained from calves at 21-28 days of age (balanced by prenatal treatment and sex) to isolate white blood cells and determine complete blood count. The white blood cells will be preserved at -80C until DNA and RNA are extracted to determine effects of prenatal stress and sex, and their possible interaction, on DNA methylation (by reduced representation bisulfite sequencing) and telomere length by quantitative polymerase chain reaction and Southern blot methods. Blood concentration of stress related hormones and metabolites will be determined by radioimmunoassays and enzyme linked immunosorbant assays. Data for both projects will be analyzed via the Statistical Analysis System (SAS) programs for repeated measures.

Progress 06/01/19 to 05/31/23

Outputs
Target Audience:Audiences that were targeted in the final year of the project were similar to previously targeted audiences (e.g., professional animal scientists, veterinarians, and beef producers via conferences and publications). Four (4) audiences were targeted to receive results accumulated during this reporting period: 1) participants in the annual meeting of the Multi-state Project W-4173 "Impacts of Stress on Performance, Health, and Well-being of Animals"; 2) participants in the March 2023 annual meeting of "The Telomere Research Network" sponsored by the National Institutes of Health; 3) participants in the "A1251 Project Directors' Meeting" in May 2023; and 4) shortly after the conclusion of the reporting period results were shared with beef cattle producers at the August 2023 Texas A&M Beef Cattle Short Course. Specifically, at the W4173 meeting (https://www.nimss.org/projects/view/mrp/outline/18815)scientific exchange was accomplished by sharing our results withanimal scientists and veterinarians from across the U.S. who work to mitigate adverse effects of stress in several livestock, avian, and aquatic species.Our results regarding the impact of prenatal stress on telomere length and adrenal axis function wereshared with a broad international, interdisciplinary biomedical group known as The Telomere Research Network (https://trn.tulane.edu). Additional stress biology scientists were informed of our findings during the USDA NIFA AFRI A1251 Project Directors meeting. The relevance of prenatal stress and fetal programming of health of calves was covered with beef cattle producers at the annual Beef Cattle Short Course. Current and future efforts will target audiences of animal and veterinary research scientists and producers by continued publication of articles in peer-reviewed journals and industrytrade magazines or extension bulletins as appropriate. Changes/Problems:Some delays were encountered with staffing, supplies, and dependence upon service laboratories in 2021. Thoughthese delays slowed the rate of progress, the project continued. Additionalstatistical assessment continues and will lead to dissemination of additional results beyond the termination date of the project. Efforts will continue by seeking other grant support to investigate tissue specific aspects of telomere dynamics in cattle of divergenttemperaments to determine if telomere length early in life predicts future health and performance. What opportunities for training and professional development has the project provided?This project has provided training and professional development for undergraduate and graduate students. Through meetings and journal article review sessions the knowledge base of the student participantswas enhanced by assessment of research literature pertinent to stress, telomere biology, and epigenetics. This prepared the students to present results at conferences and to write manuscriptsfor publication. The technical capacity of trainees was enhanced via laboratory analytic methods and statistical analyses (including informatics) related to endocrine and 'omics research. How have the results been disseminated to communities of interest?Throughout this project, the results have been disseminated to physiologists, behaviorists, and veterinarians from U.S. institutions and federal agencies as well as progressive beef cattle producers through venues such as the annual meetings of: a) the American Society of Animal Science, b) the A1251 Animal Health and Production and Animal Products: Animal Well-Being Project Directors, c) the Telomere Research Network, and d) the Texas A&M Beef Cattle Short Course. The results will be publicly available via PubMed (www.pubmed.gov) as peer-reviewed journal 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? This project demonstrated that the length of telomeres is sexually dimorphic (average telomere length was greater in female than male calves). Similarly, the serum concentration of the stress-related steroid hormone cortisol wasgreater in female than male calves. Both male and female calves from the prenatal transportation stress treatment group had shorter telomeres than did calves of the non-transported control group. Calves of calmer temperament had greater concentrations of immunoglobulin G, lesser concentrations of cortisol, and greater length oftelomeres in peripheral immune cells. These results portend that animals (calves in this case)starting life with shorter telomeres in the peripheral blood immune cells may experience greater challenges in remaining healthy and productive. The role of telomeres in regulation of productive longevity of cattle merits long-range assessment.The impact of this project is that it is an impetus to assess tissue specific rates of telomere maturation as peripheral telomere function may not be a fully reliable surrogate for non-immune tissues. Also, the findings of this project has led researchers in other institutions to study telomere biology of livestock species.

Publications

  • Type: Journal Articles Status: Published Year Published: 2023 Citation: O'Daniel, S.E, K.J. Kochan, C.R. Long, D.G. Riley, R.D. Randel, and T.H. Welsh, T.H. 2023. Comparison of telomere length in age-matched primiparous and multiparous Brahman cows. Animals 13:2325. doi:10.3390/ani13142325.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2023 Citation: Welsh, T.H. Maternal & Prenatal Stress:Impact on Telomere Length in Cattle. Presented at Telomere Research Network Annual Meeting National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, 31 March 2023
  • Type: Journal Articles Status: Submitted Year Published: 2023 Citation: Zhang, N., E.C. Baker. T.H. Welsh, Jr., and D.G. Riley. Telomere dynamics in livestock. Biology (submitted).
  • Type: Journal Articles Status: Other Year Published: 2024 Citation: Welsh, Jr. T.H., K.J. Kochan, T.B Hairgrove, R.C. Cardoso, C.R. Long, D.G. Riley, and R.D. Randel. Evaluation of prenatal transportation stress on telomere length of calves. Frontiers in Aging (Invited manuscript for a special issue entitled "Telomere Length and Attrition:A Hallmark of Aging"). To be submitted October 2023.


Progress 06/01/21 to 05/31/22

Outputs
Target Audience:Two (2)audiences were targeted to receive results accumulatedduring this reporting period: 1) participants in the March 2022 "A1251 Project Directors' Meeting"; and 2) participants in the upcoming June 2022 "Annual Meeting of the American Society of Animal Science (ASAS)". Specifically, during the A1251 Project Directors' meeting a progress report was delivered as apowerpoint/oral presentationby Zoom. Results (in form of platform and or poster presentationof an abstract) will be delivered to an audience of animal and veterinary research scientists at the upcoming ASAS meeting. Also, itis anticipated that the project's results will be summarized and presented to a third target audience: beef cattle producers at the annual Texas A&M Beef Cattle Short Course in August 2022. Changes/Problems:Some delays were encountered with staffing, supplies, and dependence upon service laboratories in 2021. During the next reporting period the remaining leukocyte samples will be extracted to complete the PCR analyses and the DNA methylation analyses. The final steps will be statistical assessment, preparation of the final report, and dissemination of results. What opportunities for training and professional development has the project provided?During this reporting period the knowledge base of the primary graduate student was enhanced by assessment of research literature pertinent to stress, telomere biology, and epigenetics. Further, the student gained added technical skill by learning to successfully process leukocytes (white blood cells) and extract nucleic acids (DNA, to later determine degree of methylation of DNA; RNA, to determine gene expression). How have the results been disseminated to communities of interest?Over the course of this reporting period, the results were disseminated to physiologists, behaviorists, and veterinarians from U.S. institutions and federal agencies during the March 2022 annual meeting of the A1251 Animal Health and Production and Animal Products: Animal Well-Being Project Directors.In addition, results have been prepared for dissemination as a presentation of an abstract report at the upcoming June 2022 annual meeting of the American Society of Animal Science in Oklahoma City, OK. The audience members will be graduate students, scientists, and veterinarians with an interest in fetal programming by means of prenatal stress. The results will be publically available via PubMed (www.pubmed.gov) upon acceptance and publication of peer-reviewed journal articles. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period we will finalize our evaluationof the effects of prenatal stress, temperament, and cortisol on telomere length of male and female beef calves of a tropically adapted beef breed (Brahman).We will complete the extraction of DNA from white blood cells of the study calves. Samples will be analyzed by two processes this year. By the first process, one set of DNA extracts will be used to determine the extent of DNA methylation byreduced representation bisulfite sequencing methodolog (hypomethylation: more active gene expression;hypermethylation, less active gene expression).By the second process, another set of DNA extracts will be used to determine telomere length by use of realt-time polymerase chain reaction methods. The results of these laboratory analyses will be assessed in conjuction with results of endocrine and behavior tests. These comparisons enable testing of the hypotheses that telomere attritution is negatively affected by prenatal transportation stress; that stress-related hormones (such as cortisol) mediate the inhibitory effect; and that the response is sexually dimorphic.After completion of data analyses and presentation of results at annual science conferences, manuscripts for professional scientific journals and lay magazines will be prepared.

Impacts
What was accomplished under these goals? The early data emergent during this reporting period indicate that prenatal transporation stress was associated with early attrition of telomere length of chromosomes found in leukocytes (white blood cells) of 1-month-old male and female Brahman calves. Consistent with our prior observations, prenatally stressed calves were more temperamental as adjudged by pen score, a subjective measure of flightiness and reactivity to the presence of a human observer. Similarly, serum concentration of cortisol (a stress-related steroid hormone) was greater in both the male and female prenatally stressed calves. Serum concentration of immunoglobulin G, a protein marker of immunity produced by leukocytes, was inversely related to serum cortisol such that it was decreased in the prenatally stressed calves, particularly the females. Telomere length of prenatally stressed female and male Brahman calves was reduced nearly 11% and 5%, respectively, by 1 month of age. By finalization of the remaining analyses, animal health may be improved by integration of knowledge about stress response genes and how stress affects the ability of telomeres to protect chromosomes. The identification of mechanisms of the enduring effects of stress can lead to sustainable solutions to improve the health, well-being and productivity of neonatal, growing livestock.

Publications

  • Type: Conference Papers and Presentations Status: Submitted Year Published: 2022 Citation: Welsh, Jr. T.H., K.J. Kochan, C.L. Wellman, T.B Haigrove, R.C. Cardoso, C.R. Long, D.R. Riley, and R.D. Randel. 2022.Evaluation of prenatal transportation stress on telomere length in neonatal Brahman calves (submission for June 2022 annual meeting of the American Society of Animal Science).


Progress 06/01/20 to 05/31/21

Outputs
Target Audience:During this reporting period oral presentations of research abstracts were deliveredin person and by virtual methods. Results were primarily shared with research animal scientists at professional society conferences. Beef cattle producers also comprised atarget audience via a proceedings paper submitted for presentation at the annual Texas A&M Beef Cattle Short Course. Changes/Problems:Some delays in collection and analysis of samples were encountered during the 2020-2021 reporting periond due to restrictions stemming from the COVID-19 pandemic. The delays are surmountable is back on track. What opportunities for training and professional development has the project provided?The project provided extensive research training and professional development of 1 B.S. student, 1 M.S. graduate student, 2 Ph.D. students, and 1 Research Associate. Via collaborative activities 2 Ph.D. candidates from other research teams gained experience regarding how to work collaboratively in an interdisciplinary manner. The primary graduate students gained experience designing and implementing a project, collecting and processing biological samples, conducting laboratory procedures, analyzing data, preparing proceedings papers for oral delivery, writing a thesis, and preparing written reports for dissemination as articles in scientific and lay-language forms of media. How have the results been disseminated to communities of interest?Over the course of this reporting period, the results were disseminated to physiologists, geneticists, endocrinologists, and nutritionists from U.S. institutions, agencies and corporations as well as from numerous non-US institutions or agencies. Abstracts were presented as posters and slide talks at international scientific conferences of endocrinologists (The Endocrine Society), animal and dairy scientists (the joint annual meeting of the American Society of Animal Science and the Canadian Society of Animal Science; Southern Section of the American Society of Animal Science). Some information was included as a small part of a broad presentation at the Western States veterinary conference. The format for the presentations were in person, hybrid, and virtual. Via internet access one M.S. thesis is available (Texas A&M University Office of Graduate Studies and Library digital archive). Via PubMed a manuscript undergoing peer-review will become accessible online . What do you plan to do during the next reporting period to accomplish the goals?During the next reporting periodwe will evaluate of the effects of prenatal stress, temperament, and cortisol on telomere length of neonatal and weaning age male and female calves on the third set of samples. Samples will be prepared for determination of degree of DNA methylation in order to associate degree of hypomethylation or hypermethylation with telomere attritution. In addition we will attempt to determine tissue specific actions of prenatal stress on telomeres, especially endocrine and immune tissues. Final analyses should provide insight regarding potential linkage of expression of biological clock genes with aging of telomeres derived from prenatally stressed calves. After completion of data analysis and presentation of results at annual meeting of the American Society for Animal Science in 2022, manuscripts for professional scientific journals and lay magazines will be prepared.

Impacts
What was accomplished under these goals? Experiments were conducted to evaluate the effects of acute inflammation (Experiment 1), parity (Experiment 2), and prentatal transportation stress (Experiment 3) on peripheral blood leukocyte telomere length (TL) in Brahman cattle. Experiment 1 utilized 11 heifers (20-21 mo of age) grouped into either control (n=6) or lipopolysaccharide (LPS) treatment (to mimic inflammatory stress response following exposure to gram negative bacteria; n=6) groups. Sickness behavior was observed post treatment. In both experiments, quantitative PCR methods were utilized to determine quantity of telomere sequences and bovine β-2-globulin gene. Statistical analyses were conducted utilizing mixed linear models with the MIX procedure of SAS. A trend was observed for increased days of age and decreased TL. The LPS treatment did elicit a febrile response observed as increased vaginal temperature. No relationship was seen between TL and treatment. A greater degree of endotoxin exposure than utilized in this study may be needed to adequately assess TL response to acute inflammation stressor. Experiment 2 involved 19 cows [primiparous (n=8) and multiparous (n=11)] sampled on d -28, d + 7, and d + 28 preand post-calving. Cows were weighed and BCS recorded on sample days as well as observed for duration of labor and calving ease. A reduction in TL was observed between parity 1 and 2. Parity was negatively associated with peripheral blood leukocyte TL in Brahman cows. Experiment 3 was conducted to assess the influence of prenatal transportation stress on peripheral blood leukocyte telomere length and on immune tissues in 28-day-old Brahman calves. Dams of controls calves were not transported during gestation whereas dams of the PNS calves were transported by trailer for 2-hour periods of time at days 60, 80, 100, 120 and 140 of gestation. Blood and tissue samples were taken from 16 male (n=8 control; n=8 PNS) and 16 female (n=8 control; n=8 PNS) calves at 28 days of age. Thymic gland weight tended to be less in PNS than control calves. Serum cortisol concentration was negatively correlated with weights of the splenic and thymic immune tissues. The DNA of isolated leukocytes was extracted and analyzed for telomere length. Disruption of continuity of effort during the corona virus (COVID-19) pandemic has temporarilydelayed laboratory analysis of all of the samples derived from leukocytes. The third batch of leukocyte samples awaitfurther laboratory analysis. Results from tissue specific analysis of genes in leukocytes versus specific endocrine and immune tissues provide examples of how we will contrast telomere results from leukocytes versus specific tissues relevant to health and well-being of neonatal cattle.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Guy, C.P., C.L. Wellman, D.G. Riley, C.R. Long, R.D. Randel, T.H. Welsh, Jr., S.H. White-Springer. 2020. President Oral Presentation Pick: Prenatal stress increases skeletal muscle mitochondrial volume density and function in yearling Brahman calves. Journal of Animal Science 98:120-120 (Abstract).
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Earnhardt, A.L, D.G. Riley, N. Ghaffari, P.K. Riggs, C.R. Long, R.C. Cardoso, R.D. Randel, and T.H. Welsh, Jr. 2021. Differential expression of circadian clock genes in the bovine neuroendocrine adrenal system. Journal of the Endocrine Society 5(Supplement 1):A66-67 (Abstract).
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Earnhardt, A.L; E.C. Baker, K.Z. Cilkiz, D.G Riley, N. Ghaffari, B.P. Littlejohn, H.C. Collins, P.K. Riggs, C.R. Long, R.C. Cardoso. 2021. evaluation of peripheral blood leukocytes as a surrogate for RNA-Seq detection of gene expression in stress axis tissues of mature Brahman cows. Journal of Animal Science 99(Supplement 2):23 (Abstract) https://doi.org/10.1093/jas/skab096.001
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Kamilar, V. S. West, B.P. Littlejohn, C.R. Long, D.G. Riley, P.K. Riggs, R.D. Randel, T.H. Welsh, Jr., and R.C. Cardoso. 2021. Evaluation of prenatal transportation stress on the number of pituitary corticotrophs in mature Brahman cows. Journal of Animal Science 99(Supplement_2):24-25 (Abstract) https://doi.org/10.1093/jas/skab096.043


Progress 06/01/19 to 05/31/20

Outputs
Target Audience:Beef cattle producers, research scientists, and animal health practitioners comprised the target audience. They were reached via oral presentations and publication of abstracts. Presentations of data were delivered at meetings of professional scientific and veterinary medicine organizations. A manuscript was submitted for publication in a professional scientifc journal in 2021. Changes/Problems:Delays in progress encountered due to COVID-19 pandemic. What opportunities for training and professional development has the project provided?The project provided research training and professional development of 1 M.S. graduate student and 1 Research Associate. The graduate student gained experience designing and implementing a project, collecting and processing biological samples, conducting laboratory procedures, analyzing data, preparing proceedings papers for oral delivery, writing a thesis, and preparing written reports for dissemination as journal articles. How have the results been disseminated to communities of interest?The information was disseminated to veterinarians, animal health experts, physiologists and nutritionists from U.S. institutions, agencies and corporations as well as from numerous non-US institutions or agencies. Two abstracts (one poster and one slide show) were presented at international scientific conferences of animal and dairy scientists (the joint annual meeting of the American Society of Animal Science and the Canadian Society of Animal Science; Southern Section of the American Society of Animal Science). Some information was included as a small part of a broad presentation at the Western States veterinary conference. One thesis was written and is now in the 2-year embargo stage via the Texas A&M University Office of Graduate Studies. One manuscript was submitted for publication in a peer-reviewed scientific journal. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting periods we will evaluate of the effects of prenatal stress, temperament, and cortisol on telomere length of neonatal and weaning age male and female calves. In addition we will attempt to determine tissue specific actions of prenatal stress on telomeres, especially endocrine and immune tissues. After completion of data analysis and presentation of results at annual meeting of the American Society for Animal Science in 2021, manuscripts for professional scientific journals and lay magazines will be prepared.

Impacts
What was accomplished under these goals? Experiments were conducted to evaluate the effects of acute inflammation (Experiment 1), parity (Experiment 2), and prentatal transportation stress (Experiment 3) on peripheral blood leukocyte telomere length (TL) in Brahman cattle. Experiment 1 utilized 11 heifers (20-21 mo of age) grouped into either control (n=6) or lipopolysaccharide (LPS) treatment (to mimic inflammatory stress response following exposure to gram negative bacteria; n=6) groups. Sickness behavior was observed post treatment. In both experiments, quantitative PCR methods were utilized to determine quantity of telomere sequences and bovine β-2-globulin gene. Statistical analyses were conducted utilizing mixed linear models with the MIX procedure of SAS. A trend was observed for increased days of age and decreased TL. The LPS treatment did elicit a febrile response observed as increased vaginal temperature. No relationship was seen between TL and treatment. A greater degree of endotoxin exposure than utilized in this study may be needed to adequately assess TL response to acute inflammation stressor. Experiment 2 involved 19 cows [primiparous (n=8) and multiparous (n=11)] sampled on d -28, d + 7, and d + 28 pre- and post-calving. Cows were weighed and BCS recorded on sample days as well as observed for duration of labor and calving ease. A reduction in TL was observed between parity 1 and 2. Parity was negatively associated with peripheral blood leukocyte TL in Brahman cows. Experiment 3 was conducted to assess the influence of prenatal transportation stress on peripheral blood leukocyte telomere length and on immune tissues in 28-day-old Brahman calves. Dams of controls calves were not transported during gestation whereas dams of the PNS calves were transported by trailer for 2-hour periods of time at days 60, 80, 100, 120 and 140 of gestation. Blood and tissue samples were taken from 16 male (n=8 control; n=8 PNS) and 16 female (n=8 control; n=8 PNS) calves at 28 days of age. Thymic gland weight tended to be less in PNS than control calves. Serum cortisol concentration was negatively correlated with weights of the splenic and thymic immune tissues. The DNA of isolated leukocytes has been extracted and stored; however, the corona virus (COVID-19) pandemic has temporarily delayed further laboratory progress on the project.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: ODaniel, S.E., D.G. Riley, K.J. Kochan, P.K. Riggs, F.M. Rouquette, R.D. Randel, and T.H. Welsh, Jr. 2019. Comparison of telomere length in age-matched primiparous and multiparous Brahman cows. J. Anim. Sci. 97(Suppl. S3):363-364 (Abstract Number PSXIII-13). https://doi.org/10.1093/jas/skz258.726
  • Type: Journal Articles Status: Submitted Year Published: 2021 Citation: ODaniel, S.E., D.G. Riley, K.J. Kochan, P.K. Riggs, F.M. Rouquette, R.D. Randel, and T.H. Welsh, Jr. Comparison of telomere length in age-matched primiparous and multiparous Brahman cows. Journal of Animal Science (submitted).
  • Type: Theses/Dissertations Status: Accepted Year Published: 2019 Citation: O'Daniel, S.E. 2019. Effect of Acute Inflammatory Events and Parity on Length of Telomeres in Brahman Cattle. Master of Science Thesis, Texas A&M University Library, College Station, Texas.
  • Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2020 Citation: Earnhardt, A.L., C.L. Wellman, S.M. West, T.B. Hairgrove, R.C. Cardoso, C.R. Long, D.G. Riley, R.D. Randel, and T.H. Welsh. 2020. Evaluation of the effect of prenatal transportation stress on endocrine and immune tissues in neonatal Brahman calves. Journal of Animal Science (abstract presented at 2020 annual meeting of the Southern Section of the American Society of Animal Science, January 2021, Chattanooga, TN).