Digital Commons Network^™

Mechanisms Of Behavioral Change In Hosts Of Toxoplasma Gondii: A Review, Olivia Grimsley

Senior Honors Theses

The parasite Toxoplasma gondii is a highly ubiquitous parasite that latently infects an estimated 33% percent of the global population. Toxoplasmosis is of obvious clinical significance due to the extremely high risks to the unborn who contract it congenitally. Less attention has been given to a more subtle aspect of latent infection, which is the behavioral alterations that are commonly experienced by those who contract the parasite. Infected individuals commonly display a variety of altered behaviors, such as increased aggression and risk-seeking behaviors, depression, higher tendency towards suicide and self-directed violence, a loss of fear response, and a greatly increased …

A System And Method For Measuring Spatially Varying Surface Appearances With A Study Of Feathers, Jessica Baron-Lis

All Dissertations

Real-world materials, particularly biological structures such as feathers exhibit complex appearances that vary spatially across their surfaces. The field of computer graphics provides a means of understanding such surfaces through material modeling which uses both analytical models and data acquired from light-surface interactions. There are many efforts within the past decade in measuring materials for graphics, but common limitations in these works include not accounting for spatially varying properties and reliance on neural networks and synthetic datasets.

Feathers from modern birds present diverse appearances due to how light interacts with their unique hierarchical microstructures. Variations in those structures lead to …

Stereotypic Behaviors And Physiological Indicators Of Stress Occur In Horses With Restricted Durations Of Turnout, Elizabeth E. Rodgers

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

The confinement of horses to stalls with limited or no turnout time restricts their natural roaming behaviors, which potentially increases stress and behavioral stereotypies. This study investigated the impact of turnout duration on behavioral and physiological stress indicators in healthy horses. Adult horses (n = 11) were enrolled in a 3 treatment (0-, 15-, and 60-minute turnout/day) Latin square design, including 3 12 d experimental periods over 6 weeks. Horses were acclimated to turnout (24.38 x 64.01m indoor arena) and stalls (2.74 x 4.87m - 3.66 x 3.66m) stalls prior to data collection on day 1. Experienced handlers managed …

Digestibility, Palatability, And Nutrient Composition Of Three Species Of Whole Prey In Three Species Of Snakes, Morgan R. Kienzle

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

Snakes in human care often lack diversity in the diet. Rodents account for the majority of meals, while wild snakes are consuming a varied diet composed of multiple different whole prey species. By feeding only one species of prey, the chance of nutrient deficiencies and other health concerns increases. To promote variety in the managed diet, two commercially available whole prey species (mice (Mus musculus) and chicks (Gallus spp.)) and one novel species (Seba’s short-tailed bats (Carollia perspicillata)), were analyzed for their dry matter (DM), organic matter (OM), crude protein (CP), crude fat …

Evaluation Of Two Different Sweet Bran Products On Beef Cattle Digestion Characteristics And A Review Of Ramp As An Alternative Step-Up Program, Emily K. Hoefling

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

Two Sweet Bran products were evaluated at 13%, 18%, and 23% inclusion of the diet on total tract digestibility and rumen fermentation parameters. Seven ruminally cannulated, heifers were used in a 6 x 7 row-column design with 21-d periods consisting of 16-d adaptation period followed by a 5-d collection. Dietary treatments were designed in a 2 x 3 factorial arrangement with 6 periods. Factors included two Sweet Bran products that differed in particle size (Sweet Bran-SP; GMD = 1.79 mm or Sweet Bran-LP; GMD = 2.51 mm) and three dietary inclusion (13%, 18%, or 23% of diet dry matter). The …

Methane Mitigation And Its Effects On Energy Utilization In Lactating Dairy Cattle, Shan C. Sherwood

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

Improved methane (CH₄) mitigation strategies are needed to achieve the greenhouse gas emission goals of the dairy industry. The first experiment was conducted to evaluate the effects of feeding black cumin (Nigella sativa) seed oil and acetate (BCA) on CH₄ production and whole-animal energy utilization. Twelve dry Jersey cows were used in a 2-period crossover design study with 28d periods. The BCA treatment was compared to a control diet with corn oil. Both BCA and corn oil were added to the base diet as a top dress. Results from this study did not show any …

Small Cereal Grain Silage Producer Practices And Key Factors To Consider For Operations, Alexa R. Simons

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

The use of small grain silage to feed livestock has grown in popularity, although the more common source of silage is annual corn. A benefit of producing small cereal grain is double cropping, harvest a forage source in the spring prior to planting the summer annual crop. Although the cereal and corn silage processes are similar there are key differences within management decisions for producers. Objective one was to understand current management decisions from Nebraska producers pre- and post- fermentation surveys along with small cereal silage samples were analyzed. Some best management practices such as the dry matter (DM), DM …

Precision Feeding Methods To Increase Nitrogen And Energy Utilization In Lactating Dairy Cows, Chloe Emily Moss Harris

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

The environmental and economic costs of overfeeding N to dairy cattle are a challenge in today’s dairy industry. Two studies were conducted to address new opportunities for precision feeding N, which is a strategy where producers strive to feed cows the precise amount of N and amino acids that meet their individual requirements.

The objective of the first study was to evaluate the effects of supplementing a rumen protected methionine (RPM) product via automatic milking system (AMS) concentrate on milk protein yield in lactating dairy cows. Fifty-one cows were randomly assigned to control (no RPM) or treatment groups. Milk yield …

Gonadotropin-Releasing Hormone Ii And Its Receptor: Novel Regulators Of Semen Quality And Follicular Function In Swine, Caitlin Elizabeth Ross

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Pigs are the only mammalian livestock species encoding functional proteins for the second form of gonadotropin-releasing hormone (GnRH-II) and its receptor (GnRHR-II). In the first study, GnRHR-II localized to developing germ cells and the connecting piece of ejaculated spermatozoa. Concurrently, GnRH-II was most abundantly produced in the testis compared with other reproductive tract organs and was present within seminal plasma. Moreover, treatment of extended semen with GnRHR-II analogues altered sperm motility, morphology, and kinematics. For remaining studies, we utilized a swine line with ubiquitous knockdown of GnRHR-II (GnRHR-II KD) developed in our laboratory. The second study demonstrated that circulating GnRH-II …

Evaluating The Economic Viability Of Feeding Hydroponic Barley Fodder To Growing Wethers, Fallon Johnson

All Graduate Reports and Creative Projects, Fall 2023 to Present

As the livestock industry combats challenges including rising feed costs and ensuring sustainable production practices, some attention is being given to hydroponic fodder as a feed source. Hydroponic fodder offers a potential alternative to traditional feed sources. Research has demonstrated hydroponic fodder production has increased water efficiency while providing a sustainable green feed source throughout the year. This study seeks to understand how using hydroponically produced barley fodder in a total mixed ration for growing wethers compares economically to feeding traditional feed sources. A stochastic simulation model is used to determine the expected total feed costs, costs of gain, and …

Greater Sage-Grouse Habitat Dynamics And Grazing, A Study Of Vegetation Indices And Survival, Codi R. Backen

All Graduate Theses and Dissertations, Fall 2023 to Present

North American rangelands are vast, open landscapes that support diverse ecosystems and provide many ecosystem services. Many wildlife call sagebrush rangelands home, including the Greater sage-grouse (sage-grouse; Centrocercus urophasianus). Sage-grouse habitat encompasses 165 million acres across western North America, and this bird has been of conservation concern as their populations drastically declined since the 1960s. Rangelands are also grazed by livestock, which has the potential to negatively affect sagebrush ecosystems when overgrazed or overstocked, which could be detrimental to sage-grouse nesting habitat. Additionally, sagebrush rangelands undergo annual variations in precipitation, temperature, growing season length, and vegetation vigor, which has …

Establishing Methods For In Vitro Static Culture Of Gut Microbiomes For Nutritional Intervention Studies, Jeremy Mathew Case

Undergraduate Honors Capstone Projects

Lipid oxidation products (LOPs), which form during high-heat processing of oils common in Western diets, are known to cause inflammation and cellular damage. While LOPs have been implicated in exacerbating colitis and promoting colon tumorigenesis in mouse models, their direct impact on the gut microbiome remains poorly understood. This capstone project aimed to develop a low-cost in vitro protocol to culture the mouse gut microbiome under anaerobic conditions, enabling future investigations into the direct effects of bioactive dietary compounds such as LOPs. The study also assessed whether viable microbial communities could be recovered from fecal samples stored at -80°C. Fecal …

Creating A Stat2 Knock-Out Rat With Crispr/Cas9 Using I-Gonad, Isabella Dejesus

Undergraduate Honors Capstone Projects

Through the use of genetically modified animals, a more holistic understanding of physiologic responses to various diseases and pathologies can be obtained^7,19. The STAT2 gene encodes a protein called Signal Transducer and Activator of Transcription 2 and is an excellent target for genetic manipulation due to its essential role in type I and III interferon signaling pathways¹¹. A member of the STAT family of transcription factors, this protein is directly involved in mediating cellular responses to various cytokines and growth factors, particularly those related to the innate immune response¹¹. While the STAT2 signaling pathway …

Sibship Analysis Of Fall And Spring Spawn Gulf Sturgeon Eggs In The Choctawhatchee River, Florida, Lyric Mccullouch

Honors Theses

The Gulf sturgeon (Acipenser oxyrinchus desotoi) is an anadromous species that inhabits rivers along the northern Gulf of Mexico. Facing challenges from overfishing and habitat alteration, the Gulf sturgeon is listed as threatened under the Endangered Species Act. This study investigated the genetic distinctiveness of fall and spring spawning groups of Gulf sturgeon in the Choctawhatchee River, a critical habitat for the species. In this study, I used microsatellite loci to analyze Gulf sturgeon eggs previously collected in the fall and spring of 2019 and 2020. The goals of this study were to verify the genetic identity of …

Ghrelin And Decision-Making: Exploring Its Role In Food Reward, Novelty-Seeking, And Cost Valuation, Serina A. Batson

Open Access Theses & Dissertations

When low energy levels are detected, Ghrelin, a peptide hormone, is produced in the fundus of the stomach. Referred to as the "hunger hormone", Ghrelin is traditionally associated with increased food intake and blood sugar levels. A key modulator in the gut-brain interaction, Ghrelin's growth hormone secretagogue receptor can be found widely across the cortico-striosomal circuit. Critical for decision-making, Ghrelin-based manipulation of this circuit can directly affect reward and cost valuation. While Ghrelin is uniformly considered to increase the valuation of food-based rewards, little research has explored its impact on non-food-based rewards or its effects on cost valuation. Therefore, to …

Clostridioides Difficile In Feral Horse Populations In Australia, Natasza M.R. Hain-Saunders, Daniel R. Knight, Andrea Harvey, Mieghan Bruce, Brian A. Hampson, Thomas V. Riley

Research outputs 2022 to 2026

Clostridioides difficile is a known cause of diarrhea and colitis in human and non-human animals. While C. difficile is regularly isolated from domesticated horses, little is known about its prevalence in wild or feral populations. In Australia, the horse population encompasses a mix of both domesticated and feral animals, with the feral population of 400,000 estimated to be the largest in the world. This study investigated the presence and characteristics of C. difficile in Australian feral horses and evaluated their potential as a source or reservoir of C. difficile in the wider community. Fecal samples (n = 380) were collected …

Revised Phylogeography Of The Common Brushtail Possum (Trichosurus Vulpecula) Reveals New Insights Into Genetic Structure Across Australia, Shelby C. Middleton, Robert A. Davis, Kenny J. Travouillon, Anna J.M. Hopkins, Harriet R. Mills, Linette S. Umbrello

Research outputs 2022 to 2026

Understanding genetic relationships within species is essential for identifying distinct genetic lineages and informing conservation strategies, particularly for species with fragmented or widespread geographic distributions. One such widespread species that has suffered declines across Australia, despite remaining common in some areas, is the common brushtail possum (Trichosurus vulpecula), a nocturnal and arboreal marsupial. Previous genetic studies on brushtail possums had limited sampling, which has precluded a comprehensive assessment of the relationships within the species and genus. Using both single nucleotide polymorphism markers and the mitochondrial cytochrome b gene, this study employed phylogenetics, ancestry coefficients, and tested genetic differentiation, to examine …

Can Assessment Of Morphometrics Correctly Predict Species In Madtoms?, Harley C. Walden

ATU Scholars Symposium

Species delineation is commonly achieved through genetic analyses, but the utility of morphometrics as an alternative method remains unclear. This study investigates whether morphometric measurements can effectively differentiate species in madtoms (Noturus spp.). A total of 10 morphometric traits were measured from 50 individuals each of three madtom species: the Slender Madtom (Noturus exilis), the Black River Madtom (Noturus maydeni), the Ozark Madtom (Noturus albater), the Ouachita Madtom (Noturus lachneri) and the Freckled Madtom (Noturus nocturnus). Random forest modeling was employed to identify which morphometric variables most accurately distinguish between …

Distribution Of Mussels In Two Intermittent Upland Streams Of The Arkansas Valley Ecoregion, Aaron A. Brady, Seth Drake, Zach Crain, Kendall Moles

ATU Scholars Symposium

Freshwater mussels are facing an increasing need for conservation due to their declining populations. More data is needed on mussel distributions, especially in tributaries of large rivers to properly conserve and restore populations. Big Shoal Creek and Little Shoal Creek are two upland-tributaries of the Arkansas River (Lake Dardanelle) in which no records exist for freshwater mussel populations. We addressed this knowledge gap by sampling a total of 9 sites in Little Shoal Creek and 18 sites in Big Shoal Creek to determine the abundance and distribution of mussels in these streams. Mussels were sampled using a timed search approach. …

Using Guano To Determine Ozark Big-Eared Bat Cave Occupancy In Arkansas​, Lark E. Sybrant

ATU Scholars Symposium

The Ozark big-eared bat (Corynorhinus townsendii ingens) is endangered in Arkansas and is known to have small populations, range restrictions, and specific habitat requirements in the Ozark-St. Francis National Forest. Beyond their known range, there are other potentially suitable areas that have not been confirmed. We aim to test whether the non-invasive genetic analysis of guano samples can identify Ozark big-eared bat cave use and expand their known range. Additional locations need to be surveyed to ensure site protection, as unknown caves are susceptible to human disturbance and damage. Twenty-five sites were surveyed at the southeastern extent of their known …

Comparing Parasitism And Resistance To Flow In Two Populations Of Elimia Virginica, Morgan G. Hicok, Abbie Tomba, Kate Green

Departmental Honors & Graduate Capstone Projects

Snails are important in freshwater ecosystems as primary consumers and are good indicators of the stability of a habitat. Trematodes are parasitic flatworms that infect freshwater snails and can cause changes in metabolic function and growth. Flow rates and water levels are now more variable due to climate change, increasing stress and dislodgment in the snail population. This study investigates how parasites, shell morphology, and native flow environment influence resistance to disturbance. Elimia populations were sampled for differences in parasitism, shell morphology, and ability to withstand high flow environments in two different rivers. Sample sites at the Potomac River were …

Ultrasonography As A Method For Identifying Biological Sex In Captive Hellbenders (Cryptobranchus Alleganiensis), Logan N. Collom

Honors Theses

The hellbender (Cryptobranchus alleganiensis) is the United States’ largest aquatic salamander and is mainly found across the eastern U.S. There are two subspecies of hellbenders, one of which is listed as endangered by the US Fish and Wildlife Service and the other considered a species of conservation concern and a candidate for listing under the Endangered Species Act. There have been several captive breeding programs established at zoos and universities across the U.S., which require a dependable method for sexing their individuals. Ultrasound imaging has previously been used to identify the sex of other amphibian species and track …

Floral Cues And Foraging Preferences In Various Species Of Wild Bumblebees, Olivia A. Dahl

The International Journal of Ecopsychology (IJE)

There are costs and benefits for plants and their pollinators. Bumblebees play a crucial role in the dynamic plant-pollinator system. Flowers co-evolved with insects, birds, and mammals toward mechanisms that benefited, described from a human perspective, both host and forager. Characteristics such color, olfactory cues, and temperature attract pollinators, with bumblebees showing preferences for blue and yellow flowers, as well as flowers that are warmer. This study aims to answer three questions: 1) How does floral temperature at different times of day predict visit length in bumblebees? 2) Does bumblebee size affect visit length? 3) Is there an interaction between …

Quantifying The Decline In Avian Biodiversity: A Global Crisis And Its Implications For Environmental Education, Canaline Osaka

The International Journal of Ecopsychology (IJE)

People care about what they love—and it’s easy to love--and fall in love, with birds. The

opportunities to promote bird diversity are legion, and applicable throughout K-12 education. For example, the Eastern Bluebird needs to nest in the cavities of dead trees, a habitat drastically denuded by large scale farming—or in specialized nesting boxes. A nationwide effort to build and install these boxes has brought the population back to healthy numbers since its 1970 low point. (Once one knows what they look like, one cannot miss these roadside homes—Western Bluebirds also benefit.) Students can also engineer bird houses and deters, …

American Letters: Albert H. Hochbaum

The International Journal of Ecopsychology (IJE)

Excerpt from: Travels and Traditions of Waterfowl (1955)

American Letters: Loren Eiseley

The International Journal of Ecopsychology (IJE)

Except from: The Bird and the Machine, The Immense Journey (1957)

Comparison Of Morphological Characteristics And Dna Sequences Of Platyhelminthes Within Dabbling And Diving Ducks Species, Elise A. Betcher, Karolyn M. Kolstad, Ashley L. Marks, Marguerite C. Reitano, Alexander J. Train

Research & Creative Achievement Day

Platyhelminthes, also known as flatworms, are among the most common parasites found in North American duck species. This phylum of parasites includes tapeworms and flukes. This study focused on identifying various Platyhelminthes found in Minnesota and Wisconsin wild ducks using both morphological characteristics and genetic sequencing. Both diving and dabbling species of ducks were used for this study, including green winged-teal (Anas carolinensis) and ring-necked ducks (Aythya collaris). Platyhelminthes were removed from legally harvested ducks and stained before examining and imaging under the microscope to identify key morphologic features for a presumptive identification. Subsequently, DNA was extracted …

Meta-Transcriptomes Of The Microbial Communities Of The Different Developmental Life Stages Of Anastrepha Ludens (Diptera: Tephritidae), Erin L. Schuenzel

School of Integrative Biological & Chemical Sciences Faculty Publications

The Mexican fruit fly, Anastrepha ludens, is a polyphagous pest that is a constant threat to US agriculture because of its proximity to citrus production in border region of the United States and Mexico. Sterile Insect Technique has been used to manage and eradicate of the Mexican Fruit Fly. SIT, however, requires millions of sterile male flies to be released each week from mass-rearing facilities. The mass-reared colonies must deal with microbial infections that reduce survivorship, fecundity and male-male competition. Meta-transcriptomics joins culturing and next generation DNA sequencing techniques to understand these changing microbial communities. This study uses advances …

A Population Study Of The Freshwater Turtles Of The Recently Expanded Lake Hydaway In Campbell County, Virginia, Joshua Sorenson

Senior Honors Theses

Freshwater turtles are an important part of the ecological systems in central Virginia. At the recently expanded Lake Hydaway, there are several turtle species for which their population characteristics were unknown, especially the prolific Eastern Painted Turtle (Chrysemys picta picta) and Red-bellied Cooter (Pseudemys rubriventris). For five weeks, the lake was surveyed for turtles using hoop nets, and the turtles were marked and measured. Population characteristics such as carapace length and sex ratio for the Eastern Painted Turtle and Red-bellied Cooter were calculated, as well as population estimates for those two species. The Red-eared Slider ( …

Survey And Analysis Of Rumen Microbiota In Yaks At Different Growth Stages, Shengwei Jin, Xinyue Liu, Yin-Cang Han, Yong-Gang Sun, Wei-Qin Ding, Ya-Qian Liu, Fa-Jie Gou, Jian-Yu Chen

The Thai Journal of Veterinary Medicine

This study investigated changes in the richness and composition of the rumen microbiome in yaks at various developmental stages. Eighteen healthy male yaks at the ages of 5 months (M5), 12 months (M12), and 24 months (M24) had samples of their rumen digesta taken for 16S rRNA gene sequencing. The 11087 amplicon sequence variations (ASVs) in total were found; the M5, M12, and M24 groups had 3585, 1146 and 5545 distinct ASVs, respectively. Alpha diversity indices Chao, Shannon, Sobs, and ace indicated significant differences among the groups. The principal coordinate analysis (PCoA) indicated significant changes in microbial community composition across …