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Interaction Of Stocking Density And The Feeding Environment In Lactating Holstein Dairy Cows, Mackenzie Andrew Campbell

Graduate College Dissertations and Theses

Stocking density serves as a sub-clinical stressor impacting natural behavior and affective state of dairy cows. However, cows rarely experience stocking density as an isolated stressor. Understanding the effects of stocking density with additional management stressors such as low-fiber diets or feed restriction is the next step in alleviating stress and improving the well-being of lactating dairy cows housed in freestall barns. The overall goal of this dissertation was to evaluate the interaction of stocking density and the feeding environment on short-term production, behavioral, ruminal fermentation, and stress responses of lactating dairy cattle.

The first two studies (Chapter 2 and …

The Effects Of Hypothalamic Brain-Derived Neurotrophic Factor On Catecholaminergic Regulation Of Cardiovascular Function., Nicholas Christopher Cruickshank

Graduate College Dissertations and Theses

Considerable evidence supports the claim that a hyperactive sympathetic nervous system (SNS) is involved in most cases of human hypertension, and therefore a more thorough understanding of the central regulation of the SNS may help elucidate novel therapeutic options. The PVN is a key region in SNS regulation of blood pressure (BP) and heart rate (HR). Stimulation of the parvocellular PVN neurons has been shown to enhance sympathetic outflow and thereby increase BP. Brain-derived neurotrophic factor (BDNF), a modulator of neuronal activity is upregulated in the paraventricular nucleus of the hypothalamus (PVN) in response to several hypertensive stimuli such as …

Chronic Stress Potentiates The Response To Intra-Bed Nucleus Of The Stria Terminalis (Bnst) Pituitary Adenylate Cyclase Activating Peptide (Pacap) Infusion., Steven Bradley King

Graduate College Dissertations and Theses

Chronic or repeated exposure to stressful stimuli can result in several maladaptive consequences, including increased anxiety-like behaviors and altered peptide expression in brain structures involved in emotion. Among these structures, the bed nucleus of the stria terminalis (BNST) has been implicated in emotional behaviors as well as regulation of hypothalamic-pituitary-adrenal (HPA) axis activity. In rodents, chronic variate stress (CVS) has been shown to increase BNST pituitary adenylate cyclase activating polypeptide (PACAP) and its cognate PAC1 receptor transcript, and BNST PACAP signaling may mediate the maladaptive changes associated with chronic stress. In order to determine whether chronic stress would potentiate the …

The Influence Of Prenatal Stress On Behaviors Associated With Schizophrenia And Autism Spectrum Disorder., Harold Bauerle

Graduate College Dissertations and Theses

Disorders such as schizophrenia (SCZ) and austism spectrum disorder (ASD) have long been associated with prenatal stress. In these three experiments, we attempted to correlate stress during gestation with behaviors considered to have good facial validity with SCZ and ASD in both juvenile and adult animals. To differentiate the effects of prenatal stress (PS) from the effects of early life stress due to a dam's behavior (MS), half of offspring animals were cross fostered to dams treated in the alternative condition as the offspring during pregnancy in experiments 2 and 3. In experiment 1, but not in 2 or 3, …

Gene Expression Noise In Stress Response As A Survival Strategy In Fluctuating Environments, Javier Garcia-Bernardo

Graduate College Dissertations and Theses

Populations of cells live in uncertain environments, where they encounter large variations in nutrients, oxygen and toxic compounds. In the fluctuating environment, cells can sense their surroundings and express proteins to protect themselves against harmful substances. However, if the stressor appears infrequently or abruptly, sensing can be too costly or too slow, and cells cannot rely solely on it. To hedge against the sudden appearance of a stressor, cell populations can also rely on phenotypic diversification through bet-hedging. In bet-hedging, cells exploit noise in gene expression or use multistable genetic networks to produce an heterogeneous distribution of resistance-conferring protein levels. …