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Evaluating A Current Athlete Assessment Program, David Fish May 2024

Evaluating A Current Athlete Assessment Program, David Fish

Electronic Theses and Dissertations

The primary purpose of this dissertation is to evaluate the effectiveness of a questionnaire designed to assess coaches’ perceptions of an athlete monitoring program. There are four reasons for this examination of perceptions: 1) it may serve as a check for understanding of how the coach takes in the information presented to them, 2) identify any gaps in the knowledge of the coach which the sport scientist may help to fill, 3) can serve to open a dialog with the coach for ways in which the information may be better tailored to help them improve their decision-making, and 4) the …


Predicting Marine Teleost Responses To Ocean Warming And Pollution, Akila Harishchandra Aug 2023

Predicting Marine Teleost Responses To Ocean Warming And Pollution, Akila Harishchandra

Electronic Theses and Dissertations

Ocean warming and pollution are two detrimental anthropogenic factors causing rapid marine ecosystem degradation recorded in the past decades. These factors alter the marine environment intolerable for many marine species, forcing them to either adapt or shift their contemporary habitat ranges to reduce the extinction risk embedded with environmental degradation. Estimating marine species’ habitat range shifts, and their potential for developing adaptive mechanisms are critical for ecosystem conservation and management, human health risk assessment, and climate change vulnerability assessments. Given that, for the first chapter of this thesis, we focused on developing a species distribution model (SDM) integrating marine species …


Climate Interactions Drive Tree Physiology And Growth In A Northeastern Forest Ecotone, Alexandra M. Barry Aug 2023

Climate Interactions Drive Tree Physiology And Growth In A Northeastern Forest Ecotone, Alexandra M. Barry

Electronic Theses and Dissertations

Climate change is a threat to global forest ecosystems. In the northeastern United States, forest trees are facing rising temperatures and increasingly inconsistent moisture regimes. In addition to long-term changes in climate conditions, there is concern about the potential for more frequent and intense climate extremes, which can have severe and rapid negative effects on tree physiology and growth. Further, climate extremes may co-occur to produce a greater magnitude of effect than the sum of their parts, with a prominent example being hot droughts, which are increasing in occurrence and severity. The impact of these and other extreme climate interactions …


The Role Of E-Liquid Constituents In E-Cigarette-Induced Cardiac Arrhythmia And Autonomic Imbalance., Cory Kucera Aug 2023

The Role Of E-Liquid Constituents In E-Cigarette-Induced Cardiac Arrhythmia And Autonomic Imbalance., Cory Kucera

Electronic Theses and Dissertations

Introduction. Accumulating evidence indicates that exposure to electronic cigarettes (e-cigs) promotes sympathetic dominance and electrophysiologic instability in the heart, potentially culminating in arrhythmogenesis. E-liquids contain various formulations of nicotine and flavorings, but the effects of specific e-liquid constituents and their concentrations on e-cig-induced autonomic imbalance and electrical dysfunction are unresolved. To that end, we tested the hypothesis that e-cigs modify cardiac autonomic balance and ventricular arrhythmogenesis in mice dependent on e-liquid constituent type and concentration. Methods. Using a crossover design and a serial exposure regimen, ECG-telemetered male C57BL/6J mice underwent whole-body exposure to e-cig aerosols generated from e-liquids containing different …


Local Forearm Heating Does Not Alter Concentrations Of Circulating Notch1 Ecd And Hspg/Cd44, Khushali Shrenik Parikh Jun 2023

Local Forearm Heating Does Not Alter Concentrations Of Circulating Notch1 Ecd And Hspg/Cd44, Khushali Shrenik Parikh

Electronic Theses and Dissertations

Endothelial dysfunction underlies the pathophysiology of cardiovascular disease. While advances have been made for treatment and management, many gaps in knowledge remain. Recently, heat therapy has gained attention for improving vascular endothelial function, tenably through increases in antegrade shear stress (SS). However, no study has examined the molecular mechanisms associated with SS and heating. Accordingly, the aim of this study was to determine how local forearm heating may impact Notch1 and Heparan Sulfate Proteoglycan (HSPG), which are transmembrane endothelial mechanosensors essential for preserving endothelial integrity and signalling. We hypothesized that 40-minutes of increased antegrade SS from forearm heating will increase …


Comparative Energetics Of Mammalian Thermoregulatory Physiology, Ana M. Breit May 2023

Comparative Energetics Of Mammalian Thermoregulatory Physiology, Ana M. Breit

Electronic Theses and Dissertations

Endothermy allows species to decouple body temperature from environmental
temperatures but does not equate to endothermic species maintaining those constant temperatures. Instead, heterothermy fluctuating body temperatures, both in and outside of torpor is common and allows endotherms to expand the limits of thermoneutrality. Thermolability is likely to be more common in the tropics and subtropics, where species live within or above their thermoneutral zone. My dissertation research focused on the heterothermic-homeothermic continuum, specifically quantifying where on the continuum different species fall at certain times and why those species have evolved to be at those points. I quantified the thermal profile …


Use Of Hematological Markers To Assess Physiological Condition And Health Status In Free-Ranging Sand Tiger Sharks (Carcharius Taurus), Chestina N. Craig Jan 2023

Use Of Hematological Markers To Assess Physiological Condition And Health Status In Free-Ranging Sand Tiger Sharks (Carcharius Taurus), Chestina N. Craig

Electronic Theses and Dissertations

The contents of blood can provide information about the physiological condition and health of vertebrates. This study seeks to better understand the stress physiology and blood bacteria presence of the sand tiger shark (Carcharius taurus), as sharks are known to have unique physiology and immune systems. In this study the blood metabolites glucose, lactate, and ketones (3-hydroxybuteric acid and acetoacetate), were used to understand how biotic and abiotic factors affect the acute stress response to capture and handling. Metabolite concentrations from blood plasma were analyzed using colorimetric assays. Glucose and ketones showed no significant responses to capture and …


Return-To-The-Platform: The Case Of A Collegiate Level Weightlifter Recovering From A Meniscus Injury, Nicholas Harden Dec 2022

Return-To-The-Platform: The Case Of A Collegiate Level Weightlifter Recovering From A Meniscus Injury, Nicholas Harden

Electronic Theses and Dissertations

The purpose of this study was to observe physiological metrics relative to training-induced adaptations in conjunction with laboratory- and competition-based performances in a super-heavyweight weightlifter recovering from a meniscus injury. A retrospective analysis was conducted on a collegiate level male weightlifter (23.2 yrs; 131.9 kg; 187.3 cm) over the course of 21-weeks post-meniscus surgery. Body mass, body fat percentage, hydration status, vastus lateralis muscle cross-sectional area, jump performance, and isometric midthigh pull were regularly assessed as part of an ongoing athlete monitoring program. Pre-injury baseline (T0) measurements were collected relative to a major national competition (COMP1). Post-injury measurements took place …


Voltage-Gated Potassium Channel Dependent Mechanisms Of Cardiovascular Adaptation To Chronic Exercise., Sean Raph Dec 2022

Voltage-Gated Potassium Channel Dependent Mechanisms Of Cardiovascular Adaptation To Chronic Exercise., Sean Raph

Electronic Theses and Dissertations

Exercise increases cardiac workload, escalating the demand for oxygen. The myocardial vasculature responds to the greater demand for oxygen by increasing blood flow to match the needs of the heart during augmented work. Increasing blood flow requires the coronary arteries dilate (a.k.a. vasodilation); this is mediated predominantly by vascular smooth muscle cell relaxation. Vasodilation is driven through inhibition of calcium influx into vascular smooth muscle cells. The prevention of calcium influx is largely mediated by efflux of potassium via potassium channels causing membrane hyperpolarization, which in turn closes voltage-dependent (or gated) calcium channels (VDCC). Changes in vascular smooth muscle cell …


Re-Engineering Cardio-Oncology Testing Using Biomimetic Heart Slice Cultures., Jessica Miller Dec 2022

Re-Engineering Cardio-Oncology Testing Using Biomimetic Heart Slice Cultures., Jessica Miller

Electronic Theses and Dissertations

28% of drug withdrawal from the market are due to unforeseen disruptions in cardiomyocyte contractility and electrophysiology. The most commonly used platforms for drug testing are in vivo animal models and in vitro cell culture models. While both have been of paramount importance for the discovery and detection of many cardiotoxicities and mechanisms of action, they lack the ability to model an intact human myocardium. This work aims to establish cardiac tissue slices, which are 300-micron thin tissue sections taken from the left ventricular myocardium, as an alternative platform for cardio-oncology studies, specifically cardiotoxicity testing. Additionally, this work aims to …


Metabolic Foundations Of Exercise-Induced Cardiac Growth., Kyle Fulghum Dec 2022

Metabolic Foundations Of Exercise-Induced Cardiac Growth., Kyle Fulghum

Electronic Theses and Dissertations

Regular aerobic exercise promotes physiological cardiac growth, which is an adaptive response thought to enable the heart to meet higher physical demands. Cardiac growth involves coordination of catabolic and anabolic activities to support ATP generation, macromolecule biosynthesis, and myocyte hypertrophy. Although previous studies suggest that exercise-induced reductions in cardiac glycolysis are critical for physiological myocyte hypertrophy, it remains unclear how exercise influences the many interlinked pathways of metabolism that support adaptive remodeling of the heart. In this thesis project, we tested the general hypothesis that aerobic exercise promotes physiological cardiac growth by coordinating myocardial metabolism to promote glucose-supported anabolic pathway …


Establishing The Efficacy Of Non-Cellular Components Of Adipose-Derived Stromal Vascular Fraction In Promoting Angiogenesis., Daniel Benson Dec 2022

Establishing The Efficacy Of Non-Cellular Components Of Adipose-Derived Stromal Vascular Fraction In Promoting Angiogenesis., Daniel Benson

Electronic Theses and Dissertations

Microvascular disease is hallmarked by pathophysiological conditions such as endothelial senescence, intimal thickening which impairs vasodilation, and regression of the capillary beds causing tissue ischemia in the myocardium or in peripheral vascular networks. Adipose-derived stromal vascular fraction (SVF) has previously demonstrated the ability to revascularize tissue. Increasing evidence shows that regenerative cells elicit their therapeutic benefit by paracrine mechanisms, leaving open extracellular vesicles (EVs) as a potential crux of the cell therapy paradigm. To test this idea, three types of gelatin methacrylate hydrogels were employed: SVF gels, EV gels derived from SVF, and blank control gels, which were used in-vitro …


Importance Of The Microhabitat And Microclimate Conditions In The Northern Gray-Cheeked Salamander (Plethodon Montanus) Across An Elevation Gradient, Trevor Chapman Dec 2022

Importance Of The Microhabitat And Microclimate Conditions In The Northern Gray-Cheeked Salamander (Plethodon Montanus) Across An Elevation Gradient, Trevor Chapman

Electronic Theses and Dissertations

The southern Appalachian Mountains have among the highest salamander diversity in the world, largely due to local speciation in the family Plethodontidae. Plethodontid salamanders (i.e., lungless salamanders) are particularly sensitive to habitat climate conditions due to their reliance on cutaneous respiration, and their immediate environmental conditions (microhabitat) likely influence their dispersion and activity more than the large-scale atmospheric conditions. The Northern Gray-cheeked salamander (Plethodon montanus) is restricted to high elevations in the Appalachian Mountains. Our goal was to investigate the relationship between P. montanus and its microhabitat by examining behavioral preference for climatic conditions, characterizing the microclimate with …


Investigating Host Defenses Of North American Salamanders Against The Recently Emerged Chytrid Pathogen, Batrachochytrium Salamandrivorans, Kenzie Pereira Aug 2022

Investigating Host Defenses Of North American Salamanders Against The Recently Emerged Chytrid Pathogen, Batrachochytrium Salamandrivorans, Kenzie Pereira

Electronic Theses and Dissertations

A recently emerged chytrid fungal pathogen, Batrachochytrium salamandrivorans (Bsal) threatens salamander biodiversity. Bsal susceptibility varies between and within salamander species, but little is known about the mechanisms underlying these differences. Susceptibility is likely influenced by numerous interacting factors, but my dissertation studied the role of host immune responses.

My first aim investigated between species differences by studying the bioactive properties of salamander skin peptides against Bsal and the related pathogen, B. dendrobatidis (Bd). Skin peptides were collected from five salamander species, used for in vitro assays, and analyzed by RP-HPLC. While skin peptides from one …


Role Of Ataxia Telangiectasia Mutated Kinase In Western-Type Diet-Induced Cardiac Outcomes Under Basal And Ischemic Conditions, Mary Wingard Dec 2021

Role Of Ataxia Telangiectasia Mutated Kinase In Western-Type Diet-Induced Cardiac Outcomes Under Basal And Ischemic Conditions, Mary Wingard

Electronic Theses and Dissertations

Ataxia-telangiectasia mutated kinase (ATM), a serine/threonine kinase, plays a role in DNA damage repair, redox sensing, and metabolism. In the heart, ATM contributes significantly in the myocardial infarction (MI)-induced cardiac remodeling with effects on fibrosis, hypertrophy, apoptosis and inflammation. This study investigates the role of ATM deficiency in 14 weeks Western-type diet (WD)-induced cardiac outcomes prior to and 1-day post-MI in a sex-specific manner using wild-type (WT) and ATM heterozygous knockout (hKO) mice. In male mice, ATM deficiency induced rapid body weight gain and preload-associated dysfunction, while WT mice displayed afterload-associated dysfunction 14 weeks post-WD. Myocyte apoptosis and hypertrophy were …


Pyridine Nucleotide Redox Potential In Coronary Smooth Muscle Couples Myocardial Blood Flow To Cardiac Metabolism., Marc Matthew Dwenger Dec 2021

Pyridine Nucleotide Redox Potential In Coronary Smooth Muscle Couples Myocardial Blood Flow To Cardiac Metabolism., Marc Matthew Dwenger

Electronic Theses and Dissertations

The maintenance of myocardial oxygen supply during stress is essential for sustaining cardiac health. Enhancement of coronary blood flow upon increases in myocardial oxygen demand (i.e., hyperemia) relies on regulation of voltage-gated K+ (Kv) channels by their intracellular β subunits (i.e., Kvβ proteins). Considering that, Kvβ proteins are aldo-keto reductases (AKRs) and regulate Kv channel gating, we tested the hypothesis that elevation of myocardial oxygen demand modifies intracellular NAD(H) in arterial myocytes. Furthermore, we tested whether the resultant change in the redox state of the pyridine nucleotide pool directly regulates coronary Kv1 channel activity. High-resolution imaging mass spectrometry and …


Role Of Meibum And Tear Phospholipids In The Evaporative Water Loss Associated With Dry Eye., Samiyyah M. Sledge Dec 2021

Role Of Meibum And Tear Phospholipids In The Evaporative Water Loss Associated With Dry Eye., Samiyyah M. Sledge

Electronic Theses and Dissertations

It is generally believed that the tear film lipid surface film inhibits the rate of evaporation (Revap) of the underlying tear aqueous. It is also generally believed that changes in the composition of the tear film lipid layer is responsible for an increase in Revap in patients with dry eye. Both of these ideas have never been proven. The purpose of the current studies was to test these ideas. Revap was measured in vitro gravimetrically. Lipid spreading was measured using Raman spectroscopy and microscopy. The influence of the following surface films on the Revap of the sub phase of physiologically …


Effects Of Varying Warmup Stimuli On Running Economy, Connor Bigenho Dec 2021

Effects Of Varying Warmup Stimuli On Running Economy, Connor Bigenho

Electronic Theses and Dissertations

Purpose: The purpose of this study was to determine the effects of two potentiating warm-up stimuli (weighted-vest strides and plyometrics) on running economy (RE) over short (5-10 minutes) and longer durations (30+ minutes) of exercise in trained distance runners. Methods: Five recreationally trained male runners were recruited to participate in this study. Each trial consisted of a 10-min self-paced warm-up on the treadmill followed by baseline RE test and baseline leg-stiffness. This was immediately followed by one of two intervention warmup protocols. The protocols consisted of either a series of plyometric movements, 6 x 10-sec strides with a …


The Influence Of Incubation Conditions On Oxygen Consumption During The Development Of Pantherophis Guttatus, Celeste Gallardo Aug 2021

The Influence Of Incubation Conditions On Oxygen Consumption During The Development Of Pantherophis Guttatus, Celeste Gallardo

Electronic Theses and Dissertations

The flexible shell of some oviparous reptiles has led to differences in nutrient mobilization and water relations when compared to their rigid-shelled counterparts. Flexible-shelled eggs gain more water during development, and because of the shell structure, yolk calcium content is higher than that of eggshells. When water availability is altered for reptiles with flexible-shelled eggs, differences in both energy and nutrient utilization are observed. This study was designed to determine the baseline metabolic rate during development for the snake, Pantherophis guttatus under normal conditions, and to observe how changes in eggshell calcium and water availability impact embryonic oxygen consumption. Eggshell …


Characterization Of The Whale Shark (Rhincodon Typus) Melanocortin-2 Receptor, Brianne Hoglin Jan 2021

Characterization Of The Whale Shark (Rhincodon Typus) Melanocortin-2 Receptor, Brianne Hoglin

Electronic Theses and Dissertations

Among bony vertebrates, the melanocortin-2 receptor ortholog is unique among the family of five melanocortin receptors on the basis that it is dependent on its accessory protein, MRAP1, for trafficking and activation, and is selective for activation by ACTH alone. Previous studies on the MC2R orthologs of select cartilaginous fish, the elephant shark (Callorhinchus milii) and the red stingray (Dasyatis akajei), revealed divergent traits in a less obligatory relationship on MRAP1 and its ability to be activated by ACTH or the MSH-sized peptides. However, observed traits were not consistent between these two cartilaginous fish species, posing …


Changes In Pregnancy - Associated Glycoproteins Associated With Fetal Age, Postpartum Interval And Evaluation Of A Chute-Side Lateral Flow Assay, Adalaide C. Kline Jan 2021

Changes In Pregnancy - Associated Glycoproteins Associated With Fetal Age, Postpartum Interval And Evaluation Of A Chute-Side Lateral Flow Assay, Adalaide C. Kline

Electronic Theses and Dissertations

No abstract provided.


Search For New Fertility Markers In Bull Sperm, Saulo Menegatti Zoca Jan 2021

Search For New Fertility Markers In Bull Sperm, Saulo Menegatti Zoca

Electronic Theses and Dissertations

No abstract provided.


Novel Quantification And Localization Of Water And Solute Transporters In The Tissues Of The Spiney Dogfish (Squalus Acanthias), Tolulope B. Ojo Jan 2021

Novel Quantification And Localization Of Water And Solute Transporters In The Tissues Of The Spiney Dogfish (Squalus Acanthias), Tolulope B. Ojo

Electronic Theses and Dissertations

The dogfish, Squalus acanthias is a marine cartilaginous elasmobranch found in the North Atlantic and Pacific oceans. Dogfish synthesize and excrete urea as a product of nitrogen metabolism. They also convert ammonia into urea and retain this urea, such that their plasma is isosmotic or slightly hyperosmotic to the surrounding seawater. To facilitate the regulation of body fluid and to maintain ionic concentrations and osmotic pressure, Dogfish use ion and solute transporters (e.g., NCC, UT-1) and aquaporin water channel proteins. Studies have identified some of the aquaporin genes in the elasmobranch genome, but their functions are mostly uncharacterized. Recent transcriptomic …


Lipid Metabolites As Energy Stores In Four Stingray Species, Lauren Moniz Jan 2021

Lipid Metabolites As Energy Stores In Four Stingray Species, Lauren Moniz

Electronic Theses and Dissertations

Assessing macronutrient transfer is important for estimating ecosystem health and structure. This nutrient transfer is facilitated through trophic position interactions and the consumption of biomass. Lipids are macronutrients that can be used to assess energy flow. Triglyceride (TAG) and free fatty acids (FFA) are important lipids that are obtained from diet and integrate into tissues. They are representative of energy stores and potential energy available for metabolic processes. In marine ecosystems, stingrays occupy the mesopredator niche, facilitating nutrient transfer from lower to higher trophic positions. Stingrays consume a variety of prey items ranging in lipid content, but how lipid metabolites …


Creating A Georgia Southern Spider Collection: Can Dna Barcoding Help?, Guy B. Hobbs Jan 2021

Creating A Georgia Southern Spider Collection: Can Dna Barcoding Help?, Guy B. Hobbs

Electronic Theses and Dissertations

With over 280 spider (Araneae) species recorded within the State of Georgia, USA, the need for a well-documented natural history collection with a usable voucher system is critical to continually assess spider diversity and their future ecological impact in this region. Spider identification can be daunting for the inexperienced taxonomist; it is time consuming and sometimes requires destructive procedures. Previous works have successfully used an alternative method, DNA barcoding, to correctly identify spider species while preserving their morphology. This study set forth to create the core of a well-documented spider collection within Georgia Southern University’s Institute for Coastal Plain Science …


Examining The Function Of Protein Acyltransferase Via The Dhhc Domain Of The Paz5 Protein In The Organism Dictyostelium Discoideum, George M. Stuart-Ranchev Dec 2020

Examining The Function Of Protein Acyltransferase Via The Dhhc Domain Of The Paz5 Protein In The Organism Dictyostelium Discoideum, George M. Stuart-Ranchev

Electronic Theses and Dissertations

Protein S-palmitoylation plays a crucial role in many biological systems. S-palmitoylation involves the post-translational attachment of palmitate to a cysteine residue through a reversible thioester linkage. S-Palmitoylation is used to modify both integral and membrane proteins, many of which are involved in intracellular trafficking, membrane localization, and signal transduction pathways. Intracellular palmitoylation is mediated by a family of protein acyltransferases (PATs). PAT mutations are associated with neurological diseases and cancer progression. Proteins in the PAT family are defined by the presence of a 51-amino acid cysteine-rich domain (CRD), which contains a highly conserved aspartate-histidine-histidine-cysteine (DHHC) motif. The …


Biophysical And Stable Isotopic Profiles Of The Salmon Louse Lepeophtheirus Salmonis (Krøyer, 1837), Emma Taccardi Aug 2020

Biophysical And Stable Isotopic Profiles Of The Salmon Louse Lepeophtheirus Salmonis (Krøyer, 1837), Emma Taccardi

Electronic Theses and Dissertations

The salmon louse Lepeophtheirus salmonis is a parasitic copepod that infects wild and farmed salmonids throughout the northern hemisphere. L. salmonis represents the largest economic hurdle of the Atlantic salmon (Salmo salar) industry, with an estimated annual cost of nearly $1 billion globally due to production losses and anti-parasitic control measures. Salmon farming in Maine has existed for decades and is a critical economic driver, yet the region is underrepresented in global sea lice research. The aim of this work was to examine parasites in the context of animal trophic transfer and characterize physiological condition by quantifying the …


Zebrafish As A Model To Understand The Impact Of Inactivity And Neuromuscular Electrical Stimulation On Duchenne Muscular Dystrophy, Elisabeth Kilroy Aug 2020

Zebrafish As A Model To Understand The Impact Of Inactivity And Neuromuscular Electrical Stimulation On Duchenne Muscular Dystrophy, Elisabeth Kilroy

Electronic Theses and Dissertations

Skeletal muscle plasticity is imperative for functional adaptation to changing demands in activity. Although a great deal is known about the structural and functional plasticity of healthy skeletal muscle, far less is known about plasticity in diseased muscle. Here, we combined the power of the zebrafish model with the adaptability of neuromuscular electrical stimulation (NMES) to study the basic mechanisms of plasticity in the zebrafish model of Duchenne Muscular Dystrophy (DMD). Four NMES paradigms, defined by their frequency, delay, and voltage, were designed to emulate the repetition and load schemes of human resistance training programs. Additionally, two inactivity paradigms were …


Bilateral Muscle Oxygenation Kinetics In Response To Repeat Sprint Cycling In Strong And Weak Individuals, John Abbott May 2020

Bilateral Muscle Oxygenation Kinetics In Response To Repeat Sprint Cycling In Strong And Weak Individuals, John Abbott

Electronic Theses and Dissertations

Repeat sprint ability has been investigated thoroughly, however optimal training methodology to improve RSA remains elusive. Both kinetic and physiological viewpoints have been used to scrutinize aspects of RSA including, initial sprint performance (anaerobic power), maximal cardiorespiratory fitness (VO2max), lactate threshold, anaerobic capacity (mean power), muscle activation (EMG), and local muscle oxygenation kinetics. To our knowledge no study has utilized maximal strength levels as a separate factor among a homogenous group of cardiorespiratory fitness individuals (as determined by peak VO2 during RSA). The purpose of this study was to better understand the relationship between maximal strength, muscular characteristics, and cycling …


Characterization And Effects Of Systemic And Ovarian Gnrh In Beef Cattle, Jerica J. J. Rich Jan 2020

Characterization And Effects Of Systemic And Ovarian Gnrh In Beef Cattle, Jerica J. J. Rich

Electronic Theses and Dissertations

Previous studies evaluating single and multiple GnRH injections at time of CIDR removal/prostaglandin injection using the 7-day CO-Synch + CIDR protocol have reported decreased interval to estrus and increased expression of estrus, or increased conception rates, respectively. Thus, the objective of experiment 1 (Chapter 3) was to compare the effects of supplementing GnRH at prostaglandin injection on expression of estrus and conception rates in beef cows and heifers synchronized with different protocols. The objective was conducted in two parts, in study 1, Beef cows (n = 161) and heifers (n = 1803) from 16 herds over three years were synchronized …