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Partial Characterization Of The Voltage-Gated Sodium Channel Gene And Molecular Detection Of Permethrin Resistance In Rhipicephalus Annulatus (Say, 1821), Guilherme M. Klafke, Hannah C. Moreno, Jason Tidwell, Robert J. Miller, Teresa Patricia Feria-Arroyo, Adalberto A. Pérez De León May 2020

Partial Characterization Of The Voltage-Gated Sodium Channel Gene And Molecular Detection Of Permethrin Resistance In Rhipicephalus Annulatus (Say, 1821), Guilherme M. Klafke, Hannah C. Moreno, Jason Tidwell, Robert J. Miller, Teresa Patricia Feria-Arroyo, Adalberto A. Pérez De León

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Highlights

  • Rhipicephalus annulatus tick is an important vector of diseases to cattle.

  • Pyrethroid resistance was detected in a field population of R. annulatus in the USA.

  • Fragments of the voltage-gated sodium channel gene of R. annulatus were sequenced.

  • A qPCR-HRM was adapted to detect pyrethroid-resistant mutations in R. annulatus.

Abstract

The cattle tick, Rhipicephalus annulatus (Say) is a vector of bovine babesiosis and responsible for direct and indirect losses to cattle producing areas located in temperate and subtropical dry regions. Resistance against pyrethroids has been reported for this species in Asia and Africa, but never before in North America. …


Association Of Single Nucleotide Polymorphisms In Bovine Heat Shock Protein 70, Cytochrome P450, Lactate Dehydrogenase, Interleukin 8 Receptor, And Melatonin Receptor 1a With Hoof And Udder Traits In Beef Cows, Maryrose Warren May 2020

Association Of Single Nucleotide Polymorphisms In Bovine Heat Shock Protein 70, Cytochrome P450, Lactate Dehydrogenase, Interleukin 8 Receptor, And Melatonin Receptor 1a With Hoof And Udder Traits In Beef Cows, Maryrose Warren

Animal Science Undergraduate Honors Theses

Hoof and udder conformation are important to the longevity and productivity of beef cattle. Selection for hoof and udder quality reduces the incidence of lameness and udder disease to improve animal welfare. Genetic selection is an effective means of improving traits such as these, especially through the use of single nucleotide polymorphism (SNP) genotyping to identify indicator traits. This study used genotype data and hoof and udder scores from previous research to determine if there is significant effect between polymorphisms of heat shock protein 70 (Hsp70), cytochrome P450 (CYP450), interleukin-8 receptor (IL8), lactate dehydrogenase (LDH), and melatonin receptor 1A (MTNR1A), …


Effect Of Dietary Spirulina Platensis On Stress Levels And Growth Of Female Broiler Chickens, Victoria Tarkington May 2020

Effect Of Dietary Spirulina Platensis On Stress Levels And Growth Of Female Broiler Chickens, Victoria Tarkington

Animal Science Undergraduate Honors Theses

This study measured the effects of dietary Spirulina platensis supplementation on heterophil to lymphocyte ratio, footpad lesions, and growth performance parameters. One hundred and eighty Ross 708 broiler females were randomly divided evenly into fifteen pens with three dietary treatments for a total of five replications per treatment (twelve birds per replicate) for five weeks. The different treatments were a control diet of 20% crude protein, a diet of 17% crude protein, and a diet of 17% crude protein with 10% S. platensis added to the feed. Body weight, feed intake, and mortality rate was not significantly different between treatments …


Amino Acid Requirements In Horses, Chan Hee Mok, Kristine L. Urschel May 2020

Amino Acid Requirements In Horses, Chan Hee Mok, Kristine L. Urschel

Animal and Food Sciences Faculty Publications

Evaluating amino acid requirements, specifically threonine requirements, in horses will enable better feed formulation and result in economic production, improved animal health, and reduced environmental pollution. However, the current knowledge of protein and amino acid requirements in horses is still limited. Because horses have a unique digestive system and consume a variety of feed ingredients, their protein digestibility may be affected than other species by different feed composition, and thus amino acid requirements are susceptible to vary between situations. Therefore, a careful evaluation of amino acid require ments with a proper method is needed for various conditions. This review will …


Surveillance Of Anaplasma Marginale In Arkansas Beef Cattle Herds, Gabriel Apple May 2020

Surveillance Of Anaplasma Marginale In Arkansas Beef Cattle Herds, Gabriel Apple

Animal Science Undergraduate Honors Theses

Anaplasmosis is an economically devastating disease in cattle that is caused by the rickettsial pathogen Anaplasma marginale. It is estimated that this parasitic bacterium causes over $300 million in expenses for the U.S. cattle industry annually. In Arkansas, the beef cattle industry is the fifth largest agricultural commodity in the state, thus necessitating a better understanding of this disease along with its prevalence. In this study, both polymerase chain reaction (PCR) and competitive enzyme-linked immunosorbent assay (ELISA) tests were used to determine the prevalence of A. marginale infection in Arkansas beef cattle on pasture in the six commonly known geographical …


Glare Reduction By Dark Facial Markings And Bills In Birds, Clara Lebow May 2020

Glare Reduction By Dark Facial Markings And Bills In Birds, Clara Lebow

Electronic Theses and Dissertations

Avian facial plumage, bill coloration, and feather microstructure may serve one or more adaptive functions. Several researchers have proposed that dark eyestripes, bills, and facial masks aid in reducing glare, however, there have been relatively few tests of this hypothesis. Dark facial markings have been shown to have an adaptive glare-reduction function in recent field studies of a few species, but this hypothesis has never been tested in a broad multispecies analysis. It is likely that feather microstructure influences feather brightness and has an effect on the efficacy of glare reduction properties of feathers. I examined the link between dark …


North Dakota Greater Sage-Grouse (Centrocercus Urophasianus) Recovery Project: Using Translocation To Prevent State-Wide Extirpation And Develop Rangewide Protocols, Kade D. Lazenby May 2020

North Dakota Greater Sage-Grouse (Centrocercus Urophasianus) Recovery Project: Using Translocation To Prevent State-Wide Extirpation And Develop Rangewide Protocols, Kade D. Lazenby

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Greater sage-grouse (Centrocurcus urophasianus; hereafter sage-grouse) are the largest grouse species in North America. Sage-grouse occupy 11 western states, extending into North Dakota. North Dakota sage-grouse population is part of the Great Plains Management Zone. Conservation of sage-grouse has been on the forefront of conservation management 1990s. In 2015 the USFWS declared sage-grouse were not warranted for listing based on significant management efforts. Translocations of sage-grouse to prevent populations from extirpation are an example of these efforts.

Translocations have been described as movement and release of animals into a novel environment. There have been more than 7200 sage-grouse …


Use Of Diatomaceous Earth And Copper Oxide Wire Particles To Control Gastrointestinal Nematodes In Lambs, Olivia Jones May 2020

Use Of Diatomaceous Earth And Copper Oxide Wire Particles To Control Gastrointestinal Nematodes In Lambs, Olivia Jones

Animal Science Undergraduate Honors Theses

Abstract

Anthelmintic resistance (AR) urges alternatives to control gastrointestinal nematodes (GIN). Copper oxide wire particles (COWP) are more efficacious when used with other dewormers and little is known on efficacy of diatomaceous earth (DE) to control gastrointestinal parasites. The objective was to examine the effects of DE and COWP on GIN control. Katahdin lambs (n = 32; ~150 d of age; 25.0 ± 1.8 kg) were randomly assigned to receive: 1) DE fed at an estimated 2% dry matter intake (with the assumption of moderate consumption of bermudagrass forage and provided supplement), 2) 1g COWP, 3) both 2% DE and …


Record Fledging Count From A Seven-Egg Clutch In The Cooper’S Hawk (Accipiter Cooperii), Robert N. Rosenfield, Sarah A. Sonsthagen, Ann Riddle-Berntsen, Evan Kuhel May 2020

Record Fledging Count From A Seven-Egg Clutch In The Cooper’S Hawk (Accipiter Cooperii), Robert N. Rosenfield, Sarah A. Sonsthagen, Ann Riddle-Berntsen, Evan Kuhel

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Cooper’s Hawks (Accipiter cooperii) typically lay 3–5 eggs per clutch, rarely 6 eggs, and there are 2 accounts of 7-egg clutches and 1 record of a maximum 8-egg clutch for the species. Brood sizes of 3–5 young are common and the previous maximum brood count is 6 young. However, in 2019, we found an urban nest in Stevens Point, Wisconsin, with 7 eggs that resulted in a record high of 7 fledglings. We genetically confirmed that the attending male sired all the offspring and the attending female laid all 7 eggs. Larger body size of the tending adults …


Tobacco Enhances Bacterial-Induced Periodontal Bone Loss In Mice., Mina Iskander May 2020

Tobacco Enhances Bacterial-Induced Periodontal Bone Loss In Mice., Mina Iskander

Electronic Theses and Dissertations

Background: Tobacco smoking is the leading environmental risk factor for periodontal diseases. Delineation of the mechanisms underlying tobacco-induced or exacerbated periodontitis is hampered by the lack of an appropriate and reliable animal model. Hypothesis: We hypothesized that Porphyromonas-gingivalis-infected, cigarette smoke-exposed mice would represent reproducible models of acute (ligature model) and chronic (oral gavage model) tobacco-enhanced periodontitis that reflect multiple aspects of the disease noted in human smokers. Methods: In a chronic oral gavage disease model, Balb/c mice (6-8 weeks, 4 groups of n = 6 per group) were exposed to smoke produced by a Teague-10 smoking machine from 1R6F research …


Cardiomyocyte Morphology Following Severe Spinal Cord Contusion In Rodents., Addison D. Riney May 2020

Cardiomyocyte Morphology Following Severe Spinal Cord Contusion In Rodents., Addison D. Riney

College of Arts & Sciences Senior Theses

Spinal cord injury (SCI) is typically a traumatic event that impacts a patient's physical, psychological, and social well-being by damaging motor and sensory neurons and altering autonomic function leading to cardiac remodeling (42). Spinal cord injuries are based on a scale of severity, with severe, high-level lesions strongly correlating to the degree of cardiovascular dysfunction. (30)(37)(41). The decline in cardiovascular function is prevalent after high thoracic SCI, with patients suffering from daily bouts of orthostatic hypotension (OH) and autonomic dysreflexia (AD), both of which prevent and delay rehabilitation efforts and lessen quality of life after …


Optimal Calving Time For Beef Cows In Southwest Missouri, Briana Rose Verploeg May 2020

Optimal Calving Time For Beef Cows In Southwest Missouri, Briana Rose Verploeg

Graduate Theses/Dissertations

The purpose of this study is to determine if a optimal time of year exists for beef producers to have cows give birth in southwest Missouri for maximal net returns from calf sales and increased cow reproductive performance. To make this determination, data were collected which included year-round forage nutritive value, calf pre-weaning growth, cow energy efficiency and reproductive performance, and income and cost values. Cow and calf field data were gathered for the 2014-2018 production years at Missouri State University’s Leo Journagan Ranch. Monthly forage samples were collected from study cow pastures from 2016 through 2018. Calf, cull cow, …


Evaluating Methods To Reduce Humpback Whale (Megaptera Novaeamgliae) Ship Strike Mortality In Nearshore Feeding Habitats Within The San Francisco Bay, Alisa Keenan May 2020

Evaluating Methods To Reduce Humpback Whale (Megaptera Novaeamgliae) Ship Strike Mortality In Nearshore Feeding Habitats Within The San Francisco Bay, Alisa Keenan

Master's Theses

Across our world’s oceans, whales are perpetually stuck and killed by large ships. Sea-based commercial trade is increasing on a global scale; therefore, more large ships are circumnavigating through biologically important whale habitats. This is of grave concern to marine resource managers, especially in the United States where major shipping corridors overlap critical whale habitat. It is feared that in these areas with high whale density, ship strikes are reducing populations of whales to levels below what is sustainable for threatened and endangered species, thereby hindering the recovery of depleted whale populations. Humpback whales, a species that is federally-listed as …


The Effects Of Total Body Proton Irradiation On Mouse Myometrium, Lillith Bulawa May 2020

The Effects Of Total Body Proton Irradiation On Mouse Myometrium, Lillith Bulawa

Undergraduate Honors Theses

The boundaries of human space exploration continue to expand with new technology and discoveries making it even more important to investigate the effects of space on biological systems. Although humans have explored space in small increments, reproductive studies must be conducted to determine if stable short- or long-term residences for humans can exist in space. This study explored the effects of whole-body proton radiation on uterine smooth muscle known as the myometrium. Two types of mice utilized in this study were C57BL/6 and B6.129S6Cybbtm1Din/J NOX2 knockout mice. C57BL/6 mice are standard laboratory mice that were used to represent the wildtype …


The Role Of Dopamine In Decision Making Processes In Drosophila Melanogaster, Michelle C. Bowers May 2020

The Role Of Dopamine In Decision Making Processes In Drosophila Melanogaster, Michelle C. Bowers

Undergraduate Honors Theses

Understanding the neural processes that mediate decision making is a relatively new field of investigation in the scientific community. With the ultimate goal of understanding how humans decide between one path and another, simpler models such as Drosophila Melanogaster, the common fruit fly, are often utilized as a way of determining the neural circuits involved in these decision-making processes. One of the most important decisions flies make is the decision of where to lay their eggs (oviposit). Choosing the proper substrate upon which to lay eggs is a crucial decision that can ultimately impact their fecundity. This paper investigates the …


Evaluation Of Novel Additives And Corn Silage As Natural Alternatives To Antibiotics For The Prevention Of Ruminal Acidosis And Liver Abscesses In Beef Finishing Cattle, Hannah C. Wilson May 2020

Evaluation Of Novel Additives And Corn Silage As Natural Alternatives To Antibiotics For The Prevention Of Ruminal Acidosis And Liver Abscesses In Beef Finishing Cattle, Hannah C. Wilson

Department of Animal Science: Dissertations, Theses, and Student Research

Receiving and finishing experiments were conducted to evaluate a non-antibiotic alternative for control of liver abscesses. There was no impact of Ramaekers Immune Primer (RAM; a proprietary blend of vitamins, minerals, prebiotics, and probiotics) treatment on overall performance. Compared to tylosin, RAM was not efficacious in reducing total liver abscesses.

A feedlot study was conducted comparing a natural feed additive (essential oils blend) at varying corn silage inclusion levels on receiving and finishing cattle performance. Inclusion of EO had no effect on performance. Feeding corn silage at greater inclusions decreased daily gain and feed efficiency but increased final body weight …


Effects Of Management For Productivity On Adult Survival Of Snowy Plovers, Eleanor P. Gaines, Stephen J. Dinsmore, Michael T. Murphy May 2020

Effects Of Management For Productivity On Adult Survival Of Snowy Plovers, Eleanor P. Gaines, Stephen J. Dinsmore, Michael T. Murphy

Biology Faculty Publications and Presentations

Understanding the factors contributing to variation in demographic parameters and their influences on population growth is fundamental to effective conservation of small populations, but this information is often not available. Among shorebirds, population growth is generally most sensitive to changes in adult survival so understanding the factors affecting this vital rate is important. We used a long‐term mark–resight dataset and Program MARK to examine the effect of management actions, initiated to improve nesting productivity, on adult survival in a threatened population of Snowy Plovers (Charadrius nivosus ) in Oregon, USA. Apparent adult survival averaged 0.71 ± 0.01 (SE), but …


Laying-Sequence Variation In Yolk Carotenoids Of Eastern Bluebirds, Jessica Barkhouse May 2020

Laying-Sequence Variation In Yolk Carotenoids Of Eastern Bluebirds, Jessica Barkhouse

Theses and Dissertations

Carotenoids are naturally occurring, fat-soluble pigments that play an important role in the embryonic development of songbirds. Female songbirds use different strategies to allocate these important maternal resources to their eggs. Little research has been done on whether North American songbirds exhibit laying sequence patterns in their allocation of carotenoids. We studied the laying-sequence variation in yolk carotenoids and egg metrics of nine full clutches of Eastern Bluebirds (Sialia sialis) in Columbus, Georgia. I predicted that Eastern Bluebirds would exhibit a brood reduction strategy, with the first-laid eggs containing a higher concentration of carotenoids than the last-laid eggs. …


Regional Differences In Wild North American River Otter (Lontra Canadensis) Behavior And Communication, Sarah Walkley May 2020

Regional Differences In Wild North American River Otter (Lontra Canadensis) Behavior And Communication, Sarah Walkley

Dissertations

This study focuses on the vocalization repertoires of wild North American river otters (Lontra canadensis) in New York and California. Although they are the same species, these two established populations of river otters are separated by a significant distance and are distinct from one another. River otters are semi-aquatic social predators that can be found throughout North America. This is the first study to examine the vocalizations of wild river otters, and results are compared across field sites in the different regions. River otter vocalizations and behaviors in New York were recorded using Bushnell Aggressor trail cameras that …


Introducing A Silverback To An Established Group Of Adult Female Western Gorillas (Gorilla Gorilla Gorilla), Claudia Martinez May 2020

Introducing A Silverback To An Established Group Of Adult Female Western Gorillas (Gorilla Gorilla Gorilla), Claudia Martinez

Theses and Dissertations

In May of 2015, an attempt to introduce a new silverback (adult male) to an established group of six western lowland gorillas (Gorilla gorilla gorilla) housed at Gladys Porter Zoo failed. The introduction process was halted and only protected contact among the gorillas was allowed. On May 1, 2018 another introduction was initiated to three adult females.Twelve months of behavioral data were compared across three time periods and two environments. We predicted that an increase in agonistic and affiliative behaviors would occur while anxious behaviors would decrease. We observed a significant increase in affiliative behavior and a significant decrease in …


Organizational Effects Of Exogenous Corticosterone On Vocal Development In A Wild Parrot, Rory Eggleston May 2020

Organizational Effects Of Exogenous Corticosterone On Vocal Development In A Wild Parrot, Rory Eggleston

Theses and Dissertations

Songbirds learn songs during a plastic phase in vocal development, similar to human vocal babbling. Research has focused on male song learning, a process influenced by gonadal steroids. Like humans, parrots are very plastic vocal learners and both sexes learn vocalizations throughout life. It is unclear how the endocrine system mediates environmental information with developing phenotypes in parrots. Corticosterone (CORT) is a sex-neutral hormone that can affect cognitive development, but its role in vocal development has not been experimentally tested in wild parrots. I quantified vocal babbling from nestling Green-rumped Parrotlets (Forpus passerinus) recorded in Venezuela. Nestlings received oral CORT-oil …


Chronoecology Of A Cave-Dwelling Orb-Weaver Spider, Meta Ovalis (Araneae: Tetragnathidae), Rebecca Steele May 2020

Chronoecology Of A Cave-Dwelling Orb-Weaver Spider, Meta Ovalis (Araneae: Tetragnathidae), Rebecca Steele

Electronic Theses and Dissertations

Circadian clocks enable coordination of essential biological and metabolic processes in relation to the 24-hour light cycle. However, there are many habitats that are not subject to this light cycle, such as the deep sea, arctic regions, and cave systems. This study analyzes the circadian pattern of isolated populations of a subterranean spider, Meta ovalis from two Tennessee caves and five Indiana caves. Locomotor activity was recorded with TriKinetics LAM50 Locomotor Activity Monitor under a 12-hour light (L), 12-hour dark (D) (LD 12:12) cycle preceding total darkness (DD). Significant differences were found within and among populations found in Tennessee cave …


Earliest Known Material Of Amia, Bowfin, From The Sentinel Butte Formation (Paleocene), Medora, North Dakota, Abby Grace Moore May 2020

Earliest Known Material Of Amia, Bowfin, From The Sentinel Butte Formation (Paleocene), Medora, North Dakota, Abby Grace Moore

Theses and Dissertations

Amia calva is an icon in the field of comparative osteology, yet we have a poor understanding of the evolution of the genus because many fossil amiid bones have gone unidentified. Here we identify new material of the genus, Amia, with evidence of two unidentified species. Previously, the oldest known material identifiable as Amia cf. A. pattersoni, was a specimen from the Paleocene epoch of Alberta, Canada approximately 58 million years in age. Fossils of the two unidentified species of Amia were found in the Sentinel Butte Formation, a geologic formation of Paleocene age (~ 60 million years …


An Analysis Of Dredge Efficiency For Surfclam And Ocean Quahog Commercial Dredges, Leanne Poussard May 2020

An Analysis Of Dredge Efficiency For Surfclam And Ocean Quahog Commercial Dredges, Leanne Poussard

Master's Theses

Between 1997 and 2011, The National Marine Fisheries Service conducted 50 depletion experiments to estimate survey gear efficiency and stock density for Atlantic surfclam (Spisula solidissima) and ocean quahog (Arctica islandica) populations using commercial hydraulic dredges. The Patch Model was formulated to estimate gear efficiency and organism density from the data. The range of efficiencies estimated is substantial, leading to uncertainty in the application of these estimates in stock assessment. Analysis of depletion experiment simulations showed that uncertainty in the estimates of gear efficiency from depletion experiments was reduced by higher numbers of dredge tows per experiment, more tow overlap …


Ecology, Behavior, And Conservation Of The Mona Coqui (Eleutherodactylus Monensis) In Puerto Rico, Jennifer Stabile May 2020

Ecology, Behavior, And Conservation Of The Mona Coqui (Eleutherodactylus Monensis) In Puerto Rico, Jennifer Stabile

Master's Projects and Capstones

The Mona Coqui (Eleutherodactylus monensis) is a medium-sized, terrestrial frog endemic to Mona Island, Puerto Rico. E. monensis is the only amphibian known to inhabit Mona Island, a small (57 km2) subtropical dry forested island located in the Caribbean between Hispaniola and Puerto Rico. E. monensis is currently listed by the IUCN (2008) as Vulnerable due to its restricted range of less than 100 km2. Other possible threats may include emerging amphibian disease (i.e. Batrachochytrium dendrobatidis (Bd)), invasive species, and climate change. An increase of eco-tourism may also pose an immediate threat to this species if measures are …


Encephalization In Commensal Raccoons: A Unique Test Of The Cognitive Buffer Hypothesis, Peter M. Anderson May 2020

Encephalization In Commensal Raccoons: A Unique Test Of The Cognitive Buffer Hypothesis, Peter M. Anderson

Electronic Theses and Dissertations

This study investigated selective pressures associated with encephalization in mammals and discussed broader implications. Relative brain size as measured by EQ (Encephalization Quotient) was compared between ecological categories. Omnivores had higher average EQ than ecological specialists. Since specialists are disproportionately affected by extinction events, selection for ecological generalism is proposed as encephalization mechanism. This mechanism may reinforce the more widely known Cognitive Buffer Hypothesis (CBH)—the idea that possessing relatively large brains has buffered lineages against environmental change. CBH is tested here by comparing EQs in Procyon lotor (raccoon) in urban and rural environments. CBH predicts that raccoons in the most …


Survival Of Off-Host Rhipicephalus (Boophilus) Annulatus (Acari: Ixodidae) Larvae In Study Arenas In Relation To Climatic Factors And Habitats In South Texas, Usa, Emily Jesselle Zamora May 2020

Survival Of Off-Host Rhipicephalus (Boophilus) Annulatus (Acari: Ixodidae) Larvae In Study Arenas In Relation To Climatic Factors And Habitats In South Texas, Usa, Emily Jesselle Zamora

Theses and Dissertations

The cattle fever tick, Rhipicephalus (Boophilus) annulatus (Say), is an economically destructive arthropod because of its ability to vector bovine babesiosis. Cattle fever ticks can spend more than 90% of their life cycle as questing larvae, but the effect of climatic factors on their off-host behavior and survival is unclear. The goal of this study was to measure the effects of specific ecological factors on off-host larvae in nature. The study was conducted in a south Texas pasture over a 20-mo period, during which time larval populations were surveyed and ambient weather variables - relative humidity and temperatures – were …


Translational Genomics For Improving Sow Fertility, Hiruni R. Wijesena May 2020

Translational Genomics For Improving Sow Fertility, Hiruni R. Wijesena

Department of Animal Science: Dissertations, Theses, and Student Research

Sow fertility traits, such as litter size and number of lifetime parities produced (reproductive longevity), are economically important. Selection for these traits is difficult because they are lowly heritable, polygenic, sex-limited, and express late in life. Age at puberty is an early indicator of reproductive longevity. Gilts that achieve puberty at an early age have a greater probability to produce more parities over their lifetime. However, measuring age at puberty is time consuming and tedious. Identifying pleiotropic polymorphisms that affect age at puberty and other fertility traits, including reproductive longevity, could help to improve the accuracy of genomic prediction for …


Impact Of Cow Size And Validation Of An Electronic Feeder To Optimize Resources In Beef Production Systems, Robert L. Ziegler May 2020

Impact Of Cow Size And Validation Of An Electronic Feeder To Optimize Resources In Beef Production Systems, Robert L. Ziegler

Department of Animal Science: Dissertations, Theses, and Student Research

Optimizing beef production systems is critical in the longevity of an enterprise. In a time of rapid change and innovation, there are increasingly more opportunities to improve efficiency of livestock production by taking advantage of new technologies. Furthermore, production environments vary drastically in all segments of the beef industry, which influence feed resource availability. Therefore, it is critical to realize the cow type that excels in a given production environment according to management objectives. To gain a better understanding of the optimal cow type in the Nebraska Sandhills, a retrospective analysis was conducted to evaluate increasing cow body weight (BW) …


The Impact Of Oxidative Stress On Postmortem Meat Quality, Nicolas J. Herrera May 2020

The Impact Of Oxidative Stress On Postmortem Meat Quality, Nicolas J. Herrera

Department of Animal Science: Dissertations, Theses, and Student Research

Tenderness is the primary factor to influence consumer palatability in fresh meat. The tenderization of muscle is dependent on proteolytic mechanisms, including calcium dependent, non-lysosomal endogenous enzymes such as calpains and proteasomes. These mechanisms have been indicated alongside apoptosis early postmortem as cascades of apoptotic events promote ideal conditions for postmortem tenderization. Recent literature has identified oxidative stress-mediated events to be linked to apoptotic activity. Oxidative stress is defined as the overwhelming production of reactive species compared to homeostatic, endogenous antioxidants present within muscle systems. These conditions exhaust antioxidant function and facilitate reactive species to alter protein, lipid, or nucleic …