Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 61

Full-Text Articles in Life Sciences

The Effect Of Spirulina Platensis Algae Inclusion In Feed Of Commercial Broilers Subjected To Cyclic Heat Stress, Kirsten Shafer Dec 2022

The Effect Of Spirulina Platensis Algae Inclusion In Feed Of Commercial Broilers Subjected To Cyclic Heat Stress, Kirsten Shafer

Graduate Theses and Dissertations

The effect of Spirulina platensis inclusion in feed of commercial broilers was evaluated over one experiment. The study aimed to investigate the effects of Spirulina platensis freshwater algae inclusion on live performance and processing characteristics of commercial broilers subjected to daily cyclic heat stress. Day old Ross 708 male broilers were placed into 8 environmentally controlled chambers. At d 21, four chambers remained on a control diet containing no algae (CON) while 4 chambers received a diet that included algae at an inclusion rate of 2.5% (ALG). An 8 hour daily cyclic heat stress (24°C to 36°C) was applied to …


Identification Of Genomic, Proteomic, And Metabolomic Signatures Associated With Pulmonary Hypertension Syndrome In Broilers, Duaa Almansaf Aug 2022

Identification Of Genomic, Proteomic, And Metabolomic Signatures Associated With Pulmonary Hypertension Syndrome In Broilers, Duaa Almansaf

Graduate Theses and Dissertations

The present dissertation contains a collection of studies that examine the genomic, proteomic, and metabolomic association to pulmonary hypertension or ascites phenotype in fast-growing broilers. Pulmonary hypertension is a multifactorial metabolic disease influenced by physiological, environmental, and nutritional factors. It is characterized by a number of structural changes including, thrombosis and adverse pulmonary vascular remodeling. Thus, the atrial pressure is increased, and the right ventricle becomes hypertrophied, resulting in heart failure and the death of the bird. Pulmonary hypertension or ascites is a global problem that has negatively impacted the economy. The increased mortality rate of broilers (25%) is estimated …


Riverscape Community Genomics Of Ozark Fishes: A Comparative Framework To Infer Ecological And Evolutionary Determinants Of Genetic Diversity, Zachery D. Zbinden Aug 2022

Riverscape Community Genomics Of Ozark Fishes: A Comparative Framework To Infer Ecological And Evolutionary Determinants Of Genetic Diversity, Zachery D. Zbinden

Graduate Theses and Dissertations

Genetic variation is a crucial component of biodiversity and represents the variability and spatial structure of alleles within and among organisms. Evolution modulates this variability over time through mutation, selection, gene flow, and genetic drift. However, our capacity to test foundational theories of population genetics has always been at the mercy of molecular approaches available to quantify patterns of genetic diversity. Initially, techniques for empirical DNA studies were in their infancy and limited by technologies and the price per unit of genetic information. Because of these constraints, our pursuits have generally been limited to investigations of one or a few …


Characterization Of Genetic Pathways Involved In Resistance To A Novel Antifungal Peptide, Kayla L. Haberman Aug 2022

Characterization Of Genetic Pathways Involved In Resistance To A Novel Antifungal Peptide, Kayla L. Haberman

Graduate Theses and Dissertations

Antibiotic resistance is increasing prevalence, particularly in Candida glabrata. This opportunistic pathogen is closely phylogenetically related to Saccharomyces cerevisiae; however, its characterization is limited. C. glabrata is only second to Candida albicans as a fungal pathogen in immunocompromised patients. Commonly resistant to azoles, the most common fungal therapy, it has become costly and challenging to treat. A histatin 5 derived antifungal peptide, KM29, has a high degree of efficacy in Candida species and S. cerevisiae. The objective of this work is to advance our understanding of the mechanism of action of KM29 against C. glabrata. Previous work in the lab …


Mitochondrial Dna Diversity, Parasite And Pathogen Occurrence, And A Potential Disease Vector In Managed And Unmanaged Honey Bee, Apis Mellifera L. Populations, Dylan Cleary Aug 2022

Mitochondrial Dna Diversity, Parasite And Pathogen Occurrence, And A Potential Disease Vector In Managed And Unmanaged Honey Bee, Apis Mellifera L. Populations, Dylan Cleary

Graduate Theses and Dissertations

The western honey bee, Apis mellifera L., is a globally important pollinator plagued by several harmful stressors impacting colony health and survival. At least eight A. mellifera subspecies were imported and continue to be the genetic ancestors of U.S. honey bee populations today. Successive genetic bottle-neck events have led to reduced genetic diversity in U.S. honey bees. First, the subset of subspecies imported into the U.S. represents only a third of A. mellifera subspecies. Next, the parasitic varroa mite reduced managed and feral populations. Third, ongoing breeding practices have selected for traits from a single genetic lineage and bred from …


The Effects Of Physical Function And Genetics On Cognition And Blood Biomarkers In Individuals At-Risk For Alzheimer’S Disease And Related Dementias, Joshua Louis Gills Aug 2022

The Effects Of Physical Function And Genetics On Cognition And Blood Biomarkers In Individuals At-Risk For Alzheimer’S Disease And Related Dementias, Joshua Louis Gills

Graduate Theses and Dissertations

Alzheimer’s disease and related dementia (ADRD) rates are expected to triple by the year 2050. Early detection and specific mitigation efforts are warranted to blunt the alarming rate. Physical function (PF) declines with age, but higher physical function is associated with better cognitive functioning in middle-to- older age individuals. Moreover, greater physical activity (PA) is associated with better global cognition; however, Apoliporotein e4 carriers may not gain the same benefits with exercise. Additionally, plasma phosphorylated tau 217 (p-tau217) has been identified as a novel diagnostic ADRD biomarker which needs further research to examine associations with risk factors. Therefore, the aims …


Validation Of Whole Genome Resequencing For Mapping The Genetics Of Ascites In Broilers And Viral Susceptibility In Layers, Katherine Pepper Lee Aug 2022

Validation Of Whole Genome Resequencing For Mapping The Genetics Of Ascites In Broilers And Viral Susceptibility In Layers, Katherine Pepper Lee

Graduate Theses and Dissertations

This dissertation focused on the efficacy and validity of whole genome resequencing (WGR) for fine mapping genetic determinants of particular traits in a given organism. Previously, our research group used WGR to identify haplotype blocks of single nucleotide polymorphisms associated with ascites resistance with some as strong candidates for use in marker-assisted selection (MAS). Chapter 2 discusses the completion of a MAS project through evaluation of ascites incidence as well as production traits of economic value to poultry producers. Thus, the MAS project also covered viability of this methodology in the industry. The MAS significantly reduced ascites incidence in broilers …


Impact Of Genetic Variation And Timescale On Diatom Salinity Stress Response, Kala M. Downey May 2022

Impact Of Genetic Variation And Timescale On Diatom Salinity Stress Response, Kala M. Downey

Graduate Theses and Dissertations

Natural environments are dynamic, and organisms must sense and respond to changing conditions. One common way organisms deal with stressful environments is through gene expression changes, allowing for stress acclimation and resistance which occurs over varying time spans in different species. The recent evolutionary history of populations could greatly influence their ability to respond successfully. An evolutionary history in disturbed or fluctuating conditions could promote increased resistance or a more rapid response to these environmental stressors. To understand the impact of genotypic variation and timescales on response and acclimation to salinity changes, we have been exploiting the abilities of euryhaline …


The Role Of Ccaat Binding Factor In The Regulation Of Catalase Gene Expression In Candida Albicans, Zahra Al-Rumaih May 2022

The Role Of Ccaat Binding Factor In The Regulation Of Catalase Gene Expression In Candida Albicans, Zahra Al-Rumaih

Graduate Theses and Dissertations

Candida albicans is a fungal opportunistic human pathogen. Its infections range from surficial infections like skin rash to fatal systemic infections. Filamentation growth mode is associated with C. albicans virulence because it helps penetration of the host’s epithelial cells. The CCAAT-binding factor (CBF) is a conserved heterooligomeric transcription factor found in 30% of eukaryotes genes. In C. albicans it is composed of 4 major subunits, including Hap2, Hap3, Hap4, and Hap5. Hap2 and Hap5 are essential for DNA binding and function. Hap4 has 3 homologous subunits: Hap41 and Hap42 are putative subunits of CBP. Hap43 is the only Hap4 subunit …


Development Of A Long-Read Sequencing Protocol To Assess The Precision And Efficacy Of Gene Editing For Duchenne Muscular Dystrophy, Landon Andrew Burcham May 2022

Development Of A Long-Read Sequencing Protocol To Assess The Precision And Efficacy Of Gene Editing For Duchenne Muscular Dystrophy, Landon Andrew Burcham

Graduate Theses and Dissertations

This work establishes a method for assessing on-target precision due to CRISPR-Cas9 gene editing, especially within the context of exon skipping therapy for Duchenne Muscular Dystrophy. The proposed method utilizes an Oxford nanopore long-read sequencing approach to sequence amplified regions of DNA that have been edited using CRISPR-Cas9. NIH3T3 and C2C12 cell lines were treated with a dual-guide CRISPR-Cas9 system, that targets and deletes exon 23 from the DMD gene in mouse samples. Deletion PCR revealed deletion of exon 23 in both DNA and cDNA samples. Additionally, sequencing using Oxford Nanopore revealed targeted exon 23 deletion as the most prevalent …


Genome-Wide Analyses Of Genomic Variation Regulating Differential Stress Responses In Japanese Quail, Steven Anthony Shumaker Dec 2021

Genome-Wide Analyses Of Genomic Variation Regulating Differential Stress Responses In Japanese Quail, Steven Anthony Shumaker

Graduate Theses and Dissertations

As consumer demands for poultry grow, producers work to improve bird productivity in both meat and egg production. This endeavor is multifaceted, as many different factors play a part in influencing the productivity of birds, including environmental conditions, overall health, and genetic potential. One aspect controlled for in all aspects of poultry production optimization is stress management. Mitigation of stress is of primary concern to producers, as improper stress management can have many deleterious effects on chickens. Stress management requires an understanding of poultry stress responses and their physiological mechanisms, which can be more deeply understood through genomic analysis. Chapter …


Divergent Selection For Water Conversion Ratio In Broiler Populations, Joseph Hiltz Dec 2021

Divergent Selection For Water Conversion Ratio In Broiler Populations, Joseph Hiltz

Graduate Theses and Dissertations

Water scarcity is a global reality and with the anticipated population growth, freshwater resources will be further strained to meet both human needs and agriculture applications. To ensure a water sustainable and food secure future, all aspects of agriculture must become more efficient. Two strategies were explored. The potential of improving water efficiency in broilers was examined. The first strategy was to develop a more efficient and accurate method for measuring water consumption/inputs in agriculture. To date, water measuring technology has lacked the necessary sophistication to assure accuracy and repeatability of low flow water usage.

After establishing a low flow …


Molecular And Genetic Studies Of Robo2 Transcriptional Regulation In The Central Nervous System Of Drosophila Melanogaster, Muna Abdal Rahim Abdal Rhida May 2021

Molecular And Genetic Studies Of Robo2 Transcriptional Regulation In The Central Nervous System Of Drosophila Melanogaster, Muna Abdal Rahim Abdal Rhida

Graduate Theses and Dissertations

Drosophila Robo2 axon guidance receptor is a member of the evolutionarily conserved Roundabout (Robo) protein family that is involved in directing axons that cross the midline to the other side of the animal body. Robo2 roles mainly depend on two factors: The functional domains of the Robo2 protein, which is extensively studied, and the dynamic transcription of robo2 in various subsets of cells throughout embryogenesis which is not fully understood. Thus, knowing robo2 enhancers that transcriptionally regulate robo2 during embryogenesis is significant. To investigate robo2 potential enhancers, we screened 17 transgenic lines of Drosophila that were generated by Janelia Research …


Dynamics Of Hybrid Zones At A Continental Scale, Bradley T. Martin May 2021

Dynamics Of Hybrid Zones At A Continental Scale, Bradley T. Martin

Graduate Theses and Dissertations

Hybridization has traditionally been viewed as a happenstance that negatively impacts populations, but is now recognized as an important evolutionary mechanism that can substantially impact the evolutionary trajectories of gene pools, influence adaptive capacity, and contravene or reinforce divergence. Physiographic processes are important drivers of dispersal, alternately funneling populations into isolation, promoting divergence, or facilitating secondary contact of diverged populations, increasing the potential for hybridization. In North America, glacial-interglacial cycles and geomorphological changes have provided a dynamic backdrop over the last two million years that promoted such oscillations of population contraction and expansion. These biogeographic processes have resulted in regional …


Gene Set Testing By Distance Correlation, Sho-Hsien Su Dec 2020

Gene Set Testing By Distance Correlation, Sho-Hsien Su

Graduate Theses and Dissertations

Pathways are the functional building blocks of complex diseases such as cancers. Pathway-level studies may provide insights on some important biological processes. Gene set test is an important tool to study the differential expression of a gene set between two groups, e.g., cancer vs normal. The differential expression of a gene set could be due to the difference in mean, variability, or both. However, most existing gene set tests only target the mean difference but overlook other types of differential expression. In this thesis, we propose to use the recently developed distance correlation for gene set testing. To assess the …


Neogene And Quaternary Events Shaped Diversification And Speciation In Bhutanese Rheophilic Fishes Of The Family Nemacheilidae (Cypriniformes) And Sisoridae (Siluriformes), Karma Wangchuk Dec 2020

Neogene And Quaternary Events Shaped Diversification And Speciation In Bhutanese Rheophilic Fishes Of The Family Nemacheilidae (Cypriniformes) And Sisoridae (Siluriformes), Karma Wangchuk

Graduate Theses and Dissertations

Biogeography of the Himalayan region [to include the Qinghai-Tibetan Plateau (QTP)] evolved over a ~30M year span, catalyzed by the collision of the Indian and Eurasian plates. The resulting uplift produced major ecological and climatic effects, that in turn drove the diversification of biodiversity. As a result, the QTP is designated as a global biodiversity hotspot particularly vulnerable to cumulative climatic effects, including shrinking distributions, declining numbers, and local extinctions. Understanding how the biodiversity within the Himalaya/ QTP was established and maintained is a necessary first step in prioritizing conservation efforts.

Fishes in global montane regions, such as the Himalaya, …


Development Of Arkansas Net Energy Equation, Katie Hilton May 2020

Development Of Arkansas Net Energy Equation, Katie Hilton

Graduate Theses and Dissertations

The modern broiler is growing at a rapid rate generating tremendous amounts of heat. A sensitive Net Energy (NE) system is needed to measure body heat production (HP) generated primarily by daily maintenance and synthesis and degradation of myofibrillar and sarcoplasmic protein. The first two chapters present evaluation of the classic way to calculate NE versus a new methodology; the Arkansas NE (Ark NE) system, with birds from two genetic lines fed diets with different AA content or different ME content in two different environmental temperatures.

Utilizing together the Net Energy maintenance (NEm), determined from indirect calorimetry, and Net Energy …


Liver Transcriptomic Analysis After Short- And Long-Term Feeding Of Soy Protein Isolate And Its Ability To Reduce Liver Steatosis In Obese Zucker Rats, Melisa Kozaczek May 2020

Liver Transcriptomic Analysis After Short- And Long-Term Feeding Of Soy Protein Isolate And Its Ability To Reduce Liver Steatosis In Obese Zucker Rats, Melisa Kozaczek

Graduate Theses and Dissertations

According to the Centers for Disease Control and Prevention (CDC) the prevalence of obesity in adults in the United States during 2017-2018 was a 42.4%, a high number considering all the risks factors associated with this disorder, such as cardiovascular disease, insulin resistance, diabetes type 2, and fatty liver disease, among others. Fatty liver disease is the accumulation of lipids in the liver that can account for more than 5 to 10% of the liver’s weight. There are two types of fatty liver disease, alcoholic fatty liver disease (AFLD), and non-alcoholic fatty liver disease (NAFLD). AFLD is the detrimental accumulation …


Evolutionary Inference From Admixed Genomes: Implications Of Hybridization For Biodiversity Dynamics And Conservation, Tyler Chafin May 2020

Evolutionary Inference From Admixed Genomes: Implications Of Hybridization For Biodiversity Dynamics And Conservation, Tyler Chafin

Graduate Theses and Dissertations

Hybridization as a macroevolutionary mechanism has been historically underappreciated among vertebrate biologists. Yet, the advent and subsequent proliferation of next-generation sequencing methods has increasingly shown hybridization to be a pervasive agent influencing evolution in many branches of the Tree of Life (to include ancestral hominids). Despite this, the dynamics of hybridization with regards to speciation and extinction remain poorly understood. To this end, I here examine the role of hybridization in the context of historical divergence and contemporary decline of several threatened and endangered North American taxa, with the goal to illuminate implications of hybridization for promoting—or impeding—population persistence in …


The Effects Of Foot And Udder Scoring On Cow And Calf Performance, Clayton Lee Mcguire Dec 2019

The Effects Of Foot And Udder Scoring On Cow And Calf Performance, Clayton Lee Mcguire

Graduate Theses and Dissertations

Foot soundness and udder conformation are essential for longevity in beef cattle. The objective of this study was to investigate the effects of foot angle (FA), claw set (CS), teat size (TS) and udder suspension (US) scores on cowherd performance. Data were analyzed for 1,685 observations on Angus-based cows over a four-year period. At weaning FA, CS, TS, and US were evaluated. Scores are based on nine-point scales. A score of one indicates straight pasterns, divergent toes, enlarged bottle shaped teats, and absence of a median suspensory ligament; nine indicates weak pasterns, curled toes, small symmetrical teats, and a tight …


Functional Importance Of Lipin Phosphorylation, Stephanie Elizabeth Hood Dec 2019

Functional Importance Of Lipin Phosphorylation, Stephanie Elizabeth Hood

Graduate Theses and Dissertations

Highly conserved throughout evolution, lipins are dual functioning proteins found from yeast to humans. Functioning in the cytoplasm as phosphatidate phosphatase enzymes (PAP), lipins produce diacylglycerol that serves as a precursor for neutral fats and membrane phospholipids. Alternatively, nuclear lipins are responsible for the regulation of metabolic genes. Interestingly, both the mammalian lipin 1 paralog and the single Drosophila Lipin ortholog are highly phosphorylated proteins. Target of rapamycin (TOR) has previously been identified as one of the kinases that controls the subcellular localization of both lipin 1 and Drosophila Lipin. However, other serine and threonine kinases are predicted to be …


Estimation Of Genetic Components Related To Infectious Bovine Keratoconjunctivitis Susceptibility In Angus And Angus Derived Cattle Produced In The Southern United States, Eric Oxford Dec 2019

Estimation Of Genetic Components Related To Infectious Bovine Keratoconjunctivitis Susceptibility In Angus And Angus Derived Cattle Produced In The Southern United States, Eric Oxford

Graduate Theses and Dissertations

The economic impact of infectious bovine keratoconjunctivitis (IBK) has been documented in many parts of the world. Many researchers have observed that prevention of this disease is very difficult given current methodologies. This is primarily due to the multifactorial nature of this disease. The objective of this dissertation was to determine the impact of IBK on calf performance and estimate genetic parameters, heritability and estimated breeding values for IBK susceptibility. Data were analyzed using PROC GLIMMIX of SAS; while genetic parameters were estimated using a linear animal model for both single- and two-traits through MTDFREML. Additional evaluations calculated heritability using …


Chasing The Genetics Of Ascites In Broilers Using Whole Genome Resequencing, Alia Parveen Dec 2019

Chasing The Genetics Of Ascites In Broilers Using Whole Genome Resequencing, Alia Parveen

Graduate Theses and Dissertations

We are using whole genome resequencing to identify chromosomal regions associated with resistance or susceptibility to ascites, a form of pulmonary hypertension syndrome, meat-type chickens. Previous Genome Wide Association Studies (GWAS) based on Single Nucleotide Polymorphisms (SNPs) have identified regions on chromosomes 2, 9 and Z. Despite several GWAS and further genotyping, there are no reliable or potential markers for ascites phenotype. We have completed screening of Copy Number Variations (CNVs) and Single Nucleotide Polymorphisms in ascites resistant and susceptible birds from the relaxed, REL, line derived from a commercial elite broiler line. DNA samples from resistant and susceptible birds …


Investigating Growth Performance And Intestinal Barrier Integrity In Heat-Stressed Modern Broilers And Their Ancestor Jungle Fowl, Travis Tabler Dec 2019

Investigating Growth Performance And Intestinal Barrier Integrity In Heat-Stressed Modern Broilers And Their Ancestor Jungle Fowl, Travis Tabler

Graduate Theses and Dissertations

Heat stress (HS) has a negative effect on poultry production sustainability due to its adverse consequence on bird welfare, health, growth, and mortality. Although modern broilers have greater gut mass and higher energy use efficiency than unselected birds, they are more vulnerable to HS that induces “leaky gut syndrome,” or increased intestinal permeability. The aim of the current study was to determine the effect of HS on growth performance and gut barrier integrity in three modern broiler lines and their ancestor the Jungle Fowl. Four chicken populations including Giant Jungle Fowl (JF), Athens Canadian Random Bred (ACRB), 1995 Arkansas Random …


Rescue And Reestablishment Of Chicken Models For Spontaneously Occurring Hashimoto’S Thyroiditis And Systemic Sclerosis/Scleroderma, Joseph Zolton Hiltz Aug 2019

Rescue And Reestablishment Of Chicken Models For Spontaneously Occurring Hashimoto’S Thyroiditis And Systemic Sclerosis/Scleroderma, Joseph Zolton Hiltz

Graduate Theses and Dissertations

The loss of biodiversity is a topic gaining popularity both in the political and scientific forums. Nearly 30 years ago researchers and politicians congregated in Rio de Janeiro (1992) to attend the first Earth Summit. It was the first meeting of its kind discussing the tangible pressing consequences of biodiversity loss as well as the potential long term ramifications. Many of the countries represented at this summit implemented short and long term plans in order to accurately measure losses of biodiversity as well as establishing organizations to help diagnose and remedy the current problems at hand. These new organizations and …


The Functional And Structural Analysis Of Drosophila Robo2 In Axon Guidance, Lafreda Janae Howard Aug 2019

The Functional And Structural Analysis Of Drosophila Robo2 In Axon Guidance, Lafreda Janae Howard

Graduate Theses and Dissertations

In animals with complex nervous systems such as mammals and insects, signaling pathways are responsible for guiding axons to their appropriate synaptic targets. Importantly, when this process is not successful during the development of an organism, outcomes include catastrophes such as human neurological diseases and disorders. It is vital to determine the underlying causes of such diseases by understanding the development of the nervous system. There are many pathways that have been identified to play a role in this, however, we lack an understanding of how these pathways can promote such diverse outcomes in different populations of neurons. These pathways …


The Evaluation Of Genetic And Phenotypic Differences Associated With Short Term Selection Of Four Different Feed Efficiency Strategies In Japanese Quail, Alex David Gilley Dec 2018

The Evaluation Of Genetic And Phenotypic Differences Associated With Short Term Selection Of Four Different Feed Efficiency Strategies In Japanese Quail, Alex David Gilley

Graduate Theses and Dissertations

The concept of feed efficiency (FE), one unit of feed required to improve one unit of desired output, is relatively simple. However multiple outputs are desired in a commercial poultry breeding program, resulting in the need for nutrients to be partitioned in a particular manner. At the broadest level, nutrients are partitioned between production and maintenance requirements. The requirements for production and maintenance varies between birds. It is the poultry breeder’s responsibility to select individuals most aligned with the breeding objective. Irrespective of the breeding objective, various related and non-related traits influence a bird’s FE. To effectively improve FE, the …


Genetic And Epigenetic Investigations On Pulmonary Hypertension Syndrome In Meat Type- Chickens, Khaloud Alzahrani Dec 2018

Genetic And Epigenetic Investigations On Pulmonary Hypertension Syndrome In Meat Type- Chickens, Khaloud Alzahrani

Graduate Theses and Dissertations

This dissertation presents a collection of studies that investigate the genetic and epigenetic associations to ascites phenotype in broiler chickens. Ascites is a significant metabolic disease associated with fast-growing meat-type chickens (broilers) and is a terminal result of pulmonary hypertension syndrome PHS. It is a multi-factorial syndrome caused by interactions between genetic, physiological, environmental, and managemental factors. It was estimated that ascites accounts for losses of about US$1 billion annually worldwide and for over 25% of broilers mortality. Although traditional and molecular genetic methods in the selection and in performance improvements, has greatly reduced ascites frequency, yet it has not …


Evaluation Of Genetic And Environmental Influences On Broiler Meat Quality, Sara Katherine Orlowski Dec 2018

Evaluation Of Genetic And Environmental Influences On Broiler Meat Quality, Sara Katherine Orlowski

Graduate Theses and Dissertations

The effect of both genetic and environmental influences on broiler meat quality were evaluated over three experiments. Selection response was assessed for broiler lines selected for high (HBY4) and low (LBY4) four day percentage breast yield which were formed from a random bred control (RAN). A modern random bred population (MRB) created in 2015 was evaluated for differences in 4 day percentage breast yield and the resulting differences in the incidence and severity of the woody breast and white striping myopathies. Additionally, the use of embryonic thermal manipulation to impact cell division and early caloric feed restriction to slow growth …


Investigation Of Bacterial Taxa As Biomarkers Of Fescue Toxicosis And Heat Stress In Grazing Beef Cows, Sarah Katherine Chewning Aug 2018

Investigation Of Bacterial Taxa As Biomarkers Of Fescue Toxicosis And Heat Stress In Grazing Beef Cows, Sarah Katherine Chewning

Graduate Theses and Dissertations

Fescue toxicosis in grazing beef cattle is caused by consumption of Ergot alkaloids associated with tall fescue (toxic fescue) and is responsible for substantial economic loss to the U.S. beef industry. Cattle consuming toxic fescue suffer adverse physiological responses, such as: hyperthermia, increased respiration rate (RR), poor reproduction and growth performance. Other adverse responses to fescue toxins include the retention of a winter hair coat and vasoconstriction in the extremities, which can lead to tissue necrosis. Identifying cattle with reduced susceptibility to fescue toxins would allow for efficient use of fescue pastures; thus, the objectives of this thesis was to: …