Dying produces human remains and is a unique period of human lives that remains poorly understood. The aims of this research were to validate the use of hair cortisol concentration (HCC) analysis in the study of stress at the end of life and to explore the effects of biocultural factors on stress experience in the last months of life. This study examined the dead from the 1st century CE Egypt, 19th-20th century Missouri, and 21st century Florida. A framework of embodiment and the good death was employed to interpret lived experience from HCC and examine the relationships between HCC, death, cause of death, duration of disease, and medical care and treatment. HCC in the dead is higher than in the living, varies considerably between individuals, and can fluctuate across the last months of life. High HCC at the end of life cannot be easily accounted for by medications, serious disease, or decomposition; are within possible biological ranges; and are dynamic. However, leaching of cortisol from the archaeological samples is likely. Duration of disease or presence of multiple medical conditions does not influence HCC. While modern medical advancements do not improve stress levels in the dead, a reduction in stress is observed following hospital entry in the past. HCC is a valid measure of stress at the end of life. The last months of life are periods of significant stress but dying is an inherently personal and dynamic experience that varies between individuals and over many months leading up to death due to the interaction of multiple biocultural factors. These findings contribute to the understanding of a unique period of individual lives, suggest that studies of HCC in bioarchaeology must focus on the dying period and be wary of leaching, and highlight the potential of HCC in palliative care research. / Dissertation / Doctor of Philosophy (PhD) / Today, death is often regarded with uncertainty and even fear, yet little is known about the experience of dying, especially in the past. Dying is difficult to study in modern people because of communication challenges and the number of complex factors at play while studies of the past are limited because human remains do not reveal how individuals felt. A better understanding of the dying experience can help bioarchaeologists clarify the relationship between dying, death, and skeletal remains and could help improve the care of dying people today. This research evaluated a new method of stress assessment to study experiences in the last months of life in archaeological, historic, and modern samples. Hair cortisol concentration (HCC) analysis measures stress hormones in human hair to reconstruct stress experience at the time the hair was growing. High levels of HCC in dead individuals from 1st century AD Egypt, 19th-20th century Missouri, and 21st century Florida indicate that dying is stressful across time and place. HCC values from the Egyptian sample were higher than most living people but were lower than other archaeological samples which may be a result of cortisol leaching out of the hair shaft after death. Although higher than living people, HCC levels still differed between individuals and across individual hair shafts, indicating that stress experience can be different between individuals and change over an individual’s final months. These differences are not a result of biological factors such as duration of disease or the presence of certain preexisting conditions suggesting that stress at the end of life is complex. Despite advancements in medicine, the modern sample displayed similar HCC levels to those from earlier historic periods and for a number of individuals from the historic sample, hospital entry led to a temporary reduction in HCC levels. Together, these findings suggest that, while modern medical advancements have not improved stress levels at the end of life, some aspects of care could reduce stress. The results of this study indicate that dying is a stressful, complex, and dynamic phenomenon that modern medical treatment alone may not be able to improve. Furthermore, studies of HCC in archaeology must focus on the effects of dying and be wary of leaching. Ultimately, HCC analysis could contribute to a greater knowledge of the dying experience, the understanding of past peoples, and improvement of the experience of dying.

Cortisol is a stress hormone which is released from the adrenals in the Hypothalamic-Pituitary-Adrenal (HPA) axis and plays a major role in animal stress response. Cortisol is used as a stress marker and can be sampled using different methods. A good non-invasive method and a good measure of chronic stress is to measure cortisol through hair. Cortisol is stored in hair for months and therefore reflects chronic stress. The aim of this study was to investigate if cortisol concentration differs depending on coat color. Hair samples from 20 black and white Border collie dogs was analysed and used in this study. Cortisol was extracted with methanol and analysed with ELISA. The results showed no significant difference between black and white coat color within the population while there were individual differences. The results also showed that the sexes do not affect the cortisol concentration. In summary, coat color (black and white) has an effect on cortisol concentration which means that the factor color does need to be taken into account when measuring cortisol through hair.

Prenatal stress has been correlated with adverse developmental outcomes affecting infant cognition and behavior. Previous studies have shown that prenatal stress can lead to increased susceptibility to adult disease but few studies have looked at the physiological stress response system by measuring the activity of the hypothalamicpituitary-adrenal (HPA) axis. Cortisol, the output of the HPA axis can be secreted in many different matrices (saliva, blood, urine, feces and hair). Most studies that do, only look at one measure of hormone production instead of examining multiple matrices. Additionally these studies do not look at the relationship between matrices. Hair provides a long-term assessment of cortisol hormone production as related to infant behavior. Four measures of cortisol representative of prenatal and postpartum periods were collected in a sample population of rhesus macaques at the NIH facility. No stress was applied to these animals and cortisol concentrations were assessed in maternal hair, infant hair, amniotic fluid, and mothers’ milk. These cortisol measures were then analyzed first to determine vii the relationships between the four measures and second to relate these cortisol values to infant behavior in the primate neonatal neurobehavioral assessment. Subjects of this study were 30 mothers and infants from the 2015 and 2016 breeding cohort. 25 of which, were unique dyads. Using four statistical analyses and 3 groupings of behavior, we found that maternal hair cortisol concentrations were correlated with different temperaments of infants, while milk cortisol concentrations were correlated with infant’s visual exploration of the environment. Additionally, an inverse relationship was found between hair cortisol concentrations and both hair cortisol concentrations with amniotic fluid cortisol. Together, the four statistical analyses show that Maternal HPA axis activation during and after pregnancy affects infant behavioral development 1 month postpartum.

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<p>Dairy calves in the preweaning period are exposed to a variety of stressors (e.g. disbudding, castration, etc.) and management practices that have the potential to influence their health and productivity later in life. Proper colostrum management at birth is the first step in ensuring calves can reach their full potential in terms of health, growth, and development, while improper management increases a calf’s risk of failed transfer of passive immunity <strong>(FTPI)</strong> which puts the calf at an increased risk of morbidity and mortality. Previous research has indicated there is a difference in colostrum management practices between dairy bull and heifer calves. Due to the marketing of dairy-beef crossbred calves as surplus animals along with dairy bull calves, there is growing interest in the treatment of these calves on farms. The first study presented here (Chapter 2) investigated the relationship between colostrum management practices on 15 farms and the prevalence of FTPI between purebred dairy and dairy-beef crossbred calves on those farms. The results of this study found no influence of calf breed (purebred dairy or dairy-beef crossbred) on the prevalence of FTPI. However, farm tended to influence FTPI. There was also a significant influence of the reported timing of the first colostrum feeding on FTPI, with calves on farms reporting feeding colostrum within 1 hour of birth having decreased odds of experiencing FTPI. In addition to colostrum management at birth, calves are exposed to several management factors during the preweaning period that can cause stressful experiences and result in negative behavioral and physiological outcomes. Early life stress, especially chronic stress, can negatively impact calves later in life. Short term stress load in calves can be quantified by measuring cortisol in the blood serum or saliva; however, these measures are not reflective of chronic stress load because they only measure circulating cortisol. The second study (Chapter 3) considered the efficacy of utilizing hair cortisol concentration <strong>(HCC)</strong> as a measure of stress load in 27 dairy calves exposed to a weekly saline injection or a weekly or biweekly repeated acute stressor (Cosyntropin injection) during the preweaning period. The results revealed no difference in HCC between the treatment groups, though salivary cortisol was increased in calves injected with Cosyntropin. Additionally, calf behavior and growth were not influenced by the treatments in this study. Overall, these studies provided insights into two areas that have not been extensively researched. First, considering dairy-beef crossbred calf management, and second investigating a method to assess chronic stress that has not been extensively researched in calves.</p>

Cognitive impairment in coronary artery disease (CAD) patients can predict poorer quality of life, dementia, and increased mortality. This study aimed to determine the association between long-term cortisol elevations and cognitive function in CAD patients. Participants were recruited at the beginning of a 1 year cardiac rehabilitation program and followed forward. Composite Z-scores were computed from tests measuring memory and executive function at baseline and 1 year. Cortisol deposition (3 months) was measured from a 20 mg, 3 cm hair sample. Analyses of covariance showed less improvement in memory function (F1,50=4.721, p=0.035) but not executive function (F1,49=0.318, p=0.575) in patients dichotomized into a high cortisol group based on a previously established reference range. Prolonged cortisol elevation may be associated with cognitive changes in subjects with CAD.

Cognitive impairment in coronary artery disease (CAD) patients can predict poorer quality of life, dementia, and increased mortality. This study aimed to determine the association between long-term cortisol elevations and cognitive function in CAD patients. Participants were recruited at the beginning of a 1 year cardiac rehabilitation program and followed forward. Composite Z-scores were computed from tests measuring memory and executive function at baseline and 1 year. Cortisol deposition (3 months) was measured from a 20 mg, 3 cm hair sample. Analyses of covariance showed less improvement in memory function (F1,50=4.721, p=0.035) but not executive function (F1,49=0.318, p=0.575) in patients dichotomized into a high cortisol group based on a previously established reference range. Prolonged cortisol elevation may be associated with cognitive changes in subjects with CAD.

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No description available.

Animal welfare is a major concern among livestock producers in the U.S. Heat stress, particularly, compromises animal welfare and productivity, causing >$2B annual economic loss to producers. The presence of toxic alkaloids within tall fescue (Schedonorus phoenix syn Lolium arundinaceum, syn Festuca arundinacea) plants induces a complex of disorders collectively known as fescue toxicosis. Summer slump, a reduction in animal performance due to heat stress, is common and evident of the symptoms. Various techniques for assessing animal physiological and behavioral responses to heat stress were explored in this dissertation, with particular emphasis on fescue toxicosis and its mitigation strategies. In the first study, the physiological and behavioral responses of heifers was evaluated when grazing either toxic tall fescue with wildtype endophyte (WE) or tall fescue with a novel endophyte (NE). Heifers (n = 24) were assigned to either WE or NE pastures for a 56-d grazing study during the summers of 2020 and 2021. Heifer average daily gain (ADG), intravaginal temperature, and degree of hair shedding were recorded during the grazing period. Blood samples were collected through coccygeal venipuncture and hair was collected from the left rump for cortisol analysis. Ear, tail, and hoof temperatures were collected for each heifer using an infrared thermal imaging camera. In 2020, heifers that grazed NE tall fescue had greater (P = 0.0160) ADG over the season (0.22 vs. 0.12 kg day-1). Hair retention score was greater (P = 0.0029) for heifers that grazed WE tall fescue compared to heifers that grazed NE tall fescue across both years. Heifers that grazed WE tall fescue had decreased ear skin temperature (P = 0.0001), tail skin temperature (P = 0.0058), and hoof surface temperature (P = 0.0075) compared to heifers that grazed NE. Heifers that grazed WE had 0.3-0.9 ºC hotter intravaginal temperatures than heifers that grazed NE, especially during daytime. Hair cortisol levels of heifers that grazed WE tall fescue were greater (P < 0.0001) compared to hair cortisol levels of heifers that grazed NE tall fescue. From 1200h-1700h each day, heifers that grazed WE tall fescue spent 1.5 more (P = 0.0003) hours standing and 0.9 fewer (P = 0.0402) hours lying down compared to heifers that grazed NE tall fescue. These results suggest that heat stress and other physiological changes in heifers grazing WE tall fescue could be mitigated by renovating pastures with NE tall fescue that does not impose any negative effects on grazing animals. The second study explored the potential benefits of consuming condensed tannins as a means of negating the effects of toxic alkaloids in tall fescue. Twelve fall-born steers were assigned to one of the two diet supplement treatments - sericea lespedeza pellets (LES) or sericea lespedeza pellets mixed with polyethylene glycol (LES+PEG) for 12 weeks during the summers of 2020 and 2021. The LES+PEG treatment served as a positive control since polyethylene glycol binds tannins, rendering them inactive in the gastrointestinal system. Animal body weight (BW), hair retention score (HRS), rectal temperature, and thermographic images were collected every 4 weeks. Hair and blood samples were also collected for cortisol analysis. Fecal and urine samples were collected and analyzed for total ergot alkaloid (TEA) concentration. Steers on LES had greater (P = 0.0033) ADG compared to steers on LES+PEG in 2021, but not in 2020 (P = 0.8707). In 2021, HRS was greater (P < 0.05) for steers fed LES+PEG compared to steers fed LES. In 2020, ear skin temperature (P < 0.0001) and hoof surface temperature (P = 0.0382) was greater in steers on LES compared to steers on LES+PEG. Rectal temperatures were lower (P = 0.02905) for steers fed LES compared to steers fed LES+PEG in 2021. Plasma cortisol levels did not differ (P ≥ 0.1566) between LES and LES+PEG treatments for both years. In 2020, hair cortisol levels did not differ (P = 0.8295) between treatments while in 2021, the hair cortisol level of steers on LES+PEG was greater (P = 0.0221) compared to hair cortisol levels of steers on LES. This study indicated some changes in animal physiology in response to dietary supplements containing condensed tannins, but results were inconsistent and further studies are needed to better understand the potential benefits of tannins in reducing the effects of toxic alkaloids consumption. In the third study, behavioral and physiological responses of ewes that grazed either mid-stage hardwood silvopastures or open pasture (OP) were compared. The study site consists of 0.27-ha of black walnut (Juglans nigra; BSP) and honeylocust (Gleditsia triacanthos; HSP) silvopastures and open pasture treatments, each replicated three times. During the summers of 2020 and 2021, thirty-six Katahdin ewes were assigned to one of the treatments for a 6-week summer grazing trial. Ewe weights were recorded for two consecutive days at the beginning and end of the study and intravaginal temperatures were recorded for two consecutive days at every 3-week intervals. Trail cameras captured animal behavior. Blood was collected via jugular venipuncture. Hair grown during the trial was collected from the loin region. Blood and hair cortisol concentrations were determined by ELISA. Ewe ADG was greater in HSP compared to OP (P = 0.0456) but did not differ with BSP (P = 0.4686) across both years. Ewes on OP had hotter (P ≤ 0.0343) intravaginal temperatures than ewes on both silvopasture treatments between 1100h-1700h. Plasma cortisol level was lower in ewes on BSP compared to ewes on OP (P = 0.0400) but did not differ with ewes on HSP (P = 0.6954) across both years. Ewes that grazed OP had greater hair cortisol levels compared to ewes on silvopasture treatments both in 2020 and 2021 (P < 0.0001). In 2020, ewes on BSP spent about 20% more time grazing than ewes on OP (P = 0.0054) while in 2021 ewes on BSP spent about 36% more time grazing than ewes on HSP (P = 0.0014). Ewes on OP spent 400% more time standing than ewes on BSP (P < 0.0001) and 750% more time standing than ewes on HSP (P < 0.0001). Ewe on OP spent 20% less time lying down compared to ewes on BSP (P < 0.0001) and 33% less time lying down compared to ewes on HSP (P < 0.0001). Hair cortisol measures and intravaginal temperature sensors can be utilized as reliable and relatively non-invasive techniques for measuring heat stress response in livestock managed in extensive grazing systems. / Doctor of Philosophy / Heat stress compromises animal welfare and productivity, causing > $2B annual economic loss to producers in the U.S. In the southeastern U.S, heat stress in livestock is largely due both to an environmental condition and to the effect of fescue toxicosis caused by toxic alkaloids. Various management strategies to mitigate the effect of heat stress in livestock due to environmental conditions or due to the effect of tall fescue toxicosis are explored in this dissertation. In the first study, behavioral and physiological responses of heifers that grazed either toxic (WE) or novel (NE) endophyte-infected tall fescue was compared. Heifers that grazed WE tall fescue had lower gains, rough hair coat, higher hair cortisol level (stress measure), cooler extremity temperature, and hotter intravaginal temperature compared to heifers that grazed NE tall fescue. These results suggest that heat stress and other physiological changes in heifers grazing WE tall fescue could be mitigated by renovating pastures with NE tall fescue, a forage cultivar that does not impose any negative physiological effects on grazing animals. In the second study, we tested the effect of condensed tannins in reducing the severity of fescue toxicosis in steers. We fed sericea lespedeza pellets to steers in a study to test this effect. All steers were fed sericea pellets, but pellets for half (6) of the steers were treated with polyethylene glycol, which inactivates the condensed tannins in the sericea lespedeza. In our study, we found that the steers fed the sericea lespedeza had higher temperatures at their extremities (ears and tail), but lower rectal temperatures than the control steers. Interestingly, the steers fed the sericea lespedeza pellets also had slicker hair coats and lower levels of hair cortisol (indicating reduced stress) in the second year compared to the control steers. This study showed some potential of condensed tannins in reducing the effects of fescue toxicosis, but needs further study to better understand the potential benefits of tannins in reducing the post-ingestive effects of fescue toxicosis. In the third study, we compared behavioral and physiological (temperature, hair, and blood cortisol) responses of ewes that grazed either mid-stage hardwood silvopastures or open pastures (OP). Ewes on OP showed signs of heat stress with higher hair cortisol levels and hotter intravaginal temperatures during the daytime compared to ewes on silvopasture treatments. Ewes on OP spent 400% more time standing compared to ewes on BSP and 750% more time standing than ewes on HSP. Ewe on OP spent 20% less time lying down compared to ewes on BSP and 33% less time lying down compared to ewes on HSP. Ewes on silvopasture treatments spent 70% less time drinking water compared to ewes on OP. Trees within the silvopasture systems can alter the micro climatic condition thus creating a suitable environment for livestock. This can ultimately reduce stress and improve overall behavioral and physiological responses of livestock in silvopastures compared to open pastures.