Animal Sciences Commons^™

Lipid Deposition In Beef Cattle, Kyra L. Elliott

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

Both the amount and types of lipid deposition in beef cattle are key determinants of carcass value and meat quality. Amounts of intramuscular, subcutaneous, and visceral fat influence carcass grading outcomes, palatability, and composition traits that are important to beef producers as well as consumers. The objectives of this thesis were to: 1) compare beef grading camera estimates of intramuscular fat to amounts of chemically extractable lipid, 2) characterize the lipidomes of beef intramuscular fat, subcutaneous fat, and lean muscle using shotgun lipidomics, and 3) identify and characterize a novel genetic variant in cattle that may have important implications for …

Characterization Of Activity Changes In Gilts During Estrus Using The NuTrack Livestock Monitoring System, Emily P. Aquino

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

Early and accurate detection of estrus in replacement gilts is essential for reproductive success and to ensure efficient production. The objective of this study was to evaluate activity changes occurring relative to first estrus of gilts and subsequent cycles. At ~ 110 days of age, 112 gilts were randomly assigned to 14 pens and placed under continuous video monitoring until the end of the trial at ~ 200 days of age. Daily boar exposure (~ 10 minutes per day) began at ~ 122 days of age. During this period, recorded observations included vulva scores (based on swelling and redness), mounting …

Evaluation Of Maternal Bovine Appeasing Substance Administration And Feed Access Time On Finishing Cattle Performance, Behavior, And Carcass Characteristics, Carsten L. Loseke

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

Novel products and bunk management techniques may significantly influence economically relevant performance metrics of feedlot cattle. The objective of the first experiment was to evaluate maternal Bovine Appeasing Substance (mBAS) administration on performance, carcass, health, and cortisol outcomes of yearling steers. Steers (n = 1,754, initial BW = 423 kg, SD = 25 kg) were received and assigned to pens for treatment allocation. Steers received either 10 mL of the mBAS or a mineral oil placebo at initial processing and reimplant. Hair samples were collected from a subset (n = 4 steers/pen) on d 0 and d 14. …

Integrating Growth Performance And Pathogen Detection To Investigate Disease Resilience In Commercial Swine, Emmalise Hope Marie Meyer

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

Disease resilience is an important trait in commercial swine production, influencing both animal health and growth performance under natural disease challenge. The primary objective of this study was to integrate growth performance data with longitudinal pathogen detection to better understand factors contributing to disease resilience in commercial pigs. A population of 1,014 pigs across four batches was monitored from weaning through the grow-finish phase, with body weights collected to calculate average daily gain (ADG). Genome-wide association analyses were conducted using BayesC and BayesIM approaches to identify genomic regions associated with growth performance. Longitudinal pathogen surveillance was performed using pen-level oral …

Tail Biting In The Nursery: Evaluating Postural, Spatial, And Behavioral Differences Between Tail Biter And Victim Pigs, Storey L. Forster

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

This study examined behavioral differences among pigs classified as tail biters, victims, or neutral during the nursery period. A total of 192 undocked nursery pigs were assigned to eight pens and monitored for 30 days using the NUtrack system. Tail biting events were identified from video observations, and pigs contributing to the top 25% of observed tail biting activity were classified as tail biters. Based on weekly tail scoring, pigs assigned a maximum tail injury score ≥ 2 were classified as victims. All other pigs were considered neutral. A total of 700 tail biting events were observed. Thirty-eight pigs …

Application Of High-Pressure Processing To Improve The Color Of Dark Beef, Kara Ann Reynolds

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

Deviation of beef from the bright cherry-red color preferred by consumers is often discounted or discarded at retail, resulting in substantial annual economic loss to the beef industry. One such deviation is dark cutting beef, which is characterized by a darker lean appearance that is undesirable to consumers and often rejected. Similarly, beef from mature cattle tends to exhibit a darker surface color, which can also reduce consumer acceptability. High-Pressure processing (HPP) has been investigated as a strategy to improve the color of dark cutting beef. Previous studies have focused on identifying pressure levels and holding times that optimize color …

Factors Affecting The Efficacy Of Free Choice Vitamin & Mineral Supplementation Programs, Tanner K. Wansing

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

While free choice vitamin and mineral supplements are widely used within the cow/calf sector, large knowledge gaps exist around the proper management of those supplements. This thesis discusses two factors affecting the efficacy of supplementation. The first interest was the stability of vitamin A when stored with a common free choice mineral supplement. This research addressed a critical data gap by generating information on vitamin A stability within the beef industry, as current data are predominantly based in the swine industry. Vitamin A was discovered to be stable until 4 months of storage regardless of storage conditions, whereas after 4 …

Effects Of Mineral Supplementation On Ovine Performance, Forage Selectivity, And Rangeland Utilization In Southern Utah, Ryan A. Spurling

All Graduate Theses and Dissertations, Fall 2023 to Present

Sheep producers in the Intermountain West region of the US rely on productive rangeland ecosystems that vary widely in forage composition and nutrient availability. As such, supplementation is often necessary to offset dietary deficiencies. Soils and forages grown on rangelands are known to be highly variable in mineral content. Even so, a third to half of the producers in the Intermountain West choose not to provide a complete mineral supplement. Rangeland environments are often characterized by rugged geographical features that make optimal supplement placement difficult. New advances in technology have allowed us to measure individual animal intake on rangelands via …

Effects Of Serum And Commercial Serum-Free Media On Development Of In Vitro Produced (Ivp) Embryos In Cattle, Kyla Miller

All Graduate Theses and Dissertations, Fall 2023 to Present

Serum-containing media has been shown to increase incidence of large offspring syndrome and to alter gene expression, protein synthesis, and cell signaling. These factors together can result in increased pregnancy loss when combined with assisted reproduction technologies. However, there are very few direct comparisons of commercial serum-free media (IVF Bioscience™) and serum-containing media on both IVF and cloned embryo development in cattle. The aim of this study was to determine the role of serum in oocyte maturation and subsequent embryo development. Three culture systems, including in vitro maturation (IVM) and in vitro culture (IVC), were used in this study. Both …

The Hitchhiker's Guide To The Host: Fleas And The History Of Pikas In North America, Josh Pletcher

All NMU Master's Theses

Parasite phylogenetics can offer windows into the cryptic evolutionary history of hosts, often highlighting events that are not recorded by the phylogenetics of the host. Pikas (small lagomorphs) host a diverse parasite community comprising endoparasites (e.g., coccidians, nematodes, and cestodes) and ectoparasites (e.g., fleas and mites). Phylogenetic analysis of pika endoparasites has revealed pikas evolved in Asia and colonized North America in two waves, and that contact between these two pika lineages allowed parasites to be transferred from one lineage to another and to survive the extinction of their original host. To uncover these cryptic histories, understanding the biogeography of …

Mammalian Biodiversity Of The Easley Conservation Stewardship Area, Grayson C. Belt

Honors College Theses

Monitoring wildlife is an important part of conservation and is particularly vital for newly acquired conservation areas to provide a baseline of what is present. In 2025, the 22 ha Murray State University Easley Conservation Stewardship Area (MSU ECSA) was established following a donation to the university by Melissa Easley. I conducted a survey using trail cameras at the ECSA in fall 2025 and winter 2025/26 to record mammalian diversity. The survey consisted of two subprojects: a mesomammal subproject of 18 knee height trail cams and a small mammal subproject using 15 custom small mammal bucket cameras. I uploaded all …

Gaining Mussel: Evaluating Reintroduction Success Of Native Freshwater Mussels In Nebraska And Eastern Wyoming, Travis A. Moore

School of Natural Resources: Dissertations, Theses, and Student Research

Freshwater mussels are one of the most imperiled groups of organisms in North America, with over two-thirds of species considered threatened, endangered, or of special concern. These long-lived bivalves are essential to stream ecosystems, acting as filter feeders that improve water quality and as indicators of aquatic health. In Nebraska and Wyoming, native mussel populations have declined sharply due to habitat modification, pollution, and reduced connectivity. Two species of particular concern are the Plain Pocketbook Lampsilis cardium, listed as Tier I at-risk in Nebraska, and the Fatmucket Lampsilis siliquoidea, a Tier II at-risk species. In response, state agencies …

Honeybee Colony Response To Probiotic Supplementation And Grazing Practices, Katya M. Busenitz

Department of Entomology: Dissertations, Theses, and Student Research

Honeybee health is a complicated issue. Studies were conducted to scale honeybee (Apis mellifera) health from the microbiome to the landscape. Colony health parameters were measured in response to probiotic administration. Colony capped brood production, colony summer weight gain, and Varroa mite incidence were measured. I found that applications of over-the-counter probiotics did not improve the measured parameters of honeybee health compared to a control group. Results suggest that probiotic application was not beneficial but positive benefits may depend on application method, brand, or strain of probiotics used. I also examined how colony health metrics responded to different …

Linking North American Demographic Trends To Mexican Non-Breeding Grounds In A Migratory Warbler, Majuwana Gamage Dulanthi Dileka Kariyawasam

Theses and Dissertations

Migration enables species to exploit seasonal resources despite high energetic costs and mortality risks, making it a key focus for conservation under environmental change. I investigated migratory connectivity in Orange-crowned Warblers using stable hydrogen isotopes (δ²H) from feathers collected at nine non-breeding sites across Mexico. Results indicated generally weak connectivity (MC = 0.18), with most sites hosting individuals from six breeding clusters across Canada and the United States. However, one northwestern breeding group showed strong connectivity, suggesting crosswise migration to eastern Mexico. By integrating these findings with long-term Breeding Bird Survey data, I detected contrasting population trends, with Pacific Coast …

Ontogeny And The Effects Of Perinatal Stress In The First Immature Skeleton Of Teleoceras Aepysoma (Perissodactyla, Rhinocerotidae), Joe Gajewski

Electronic Theses and Dissertations

Recovery of an immature fossil rhinoceros (Teleoceras aepysoma) skeleton (ETMNH 32999) from the Gray Fossil Site in Tennessee offers the first insights into the ontogeny of the species. ETMNH 32999 is interpreted to be a subadult male in an age class equivalent to ~17-20% of potential lifespan. Comparative analyses support the hypothesis that subadults of related taxa are typically ~91% of average adult size in most dimensions. However, certain cranial dimensions are substantially lower than expected in ETMNH 32999, averaging only ~74% of the average conspecific adult. Such departure from typical growth rates is suggested to be attributable …

Landscape Connectivity And Wildlife Access To Water Across An International Border: Barriers And Opportunities For Facilitating Transboundary Movement, Bogdan Chivoiu, Erin L. Koen, Michael J. Osland, Christopher A. Gabler, Jerald T. Garrett, Ernesto Reyes, Stephanie A. Bilodeau, Mitch A. Sternberg, Jude A. Benavides, James Martinez

School of Earth, Environmental, & Marine Sciences Faculty Publications

Rapid global acceleration in the construction of physical barriers along international borders has greatly influenced biodiversity and animal movement. Physical barriers can fragment landscapes, hinder access to essential resources, impact long-distance migrations, and inhibit dispersal and gene flow. The effects of physical barriers on animal movement and landscape connectivity can be exacerbated in dryland environments where access to water is a limiting factor. In recent decades, the construction of border barrier infrastructure has accelerated along the international boundary between the United States and Mexico. Here, we used a landscape connectivity model to investigate the effects of barriers on wildlife access …

Developing An Independent Shallow-Water Survey For The Western Rock Lobster Fishery: Tracking Pre-Recruitment Abundance And Habitat Change, Lucy Rudd, Simon De Lestang, Owen Young, Benjamin Hebiton

Fisheries Research Reports

Background

Puerulus settlement has proven to be a good forecaster of legal recruitment of Western Rock Lobster entering into the commercial and recreational fisheries. However, in 2011, this relationship broke down, with average puerulus settlement levels not being reflected in commercial catch rates four years later. Some northern areas showed unexpectedly low catch rates, while other southern areas showed unexpectedly high catch rates. Since this change followed the 2011 marine heatwave, it was assumed that this event changed some component(s) which were important to the growth and survival of juvenile lobsters. It was determined that a better understanding of this …

Feeding Ecology In Coastal Systems, Randi L. Cannon

Graduate Theses and Dissertations (2019 - present)

Oysters (Crassostrea virginica) are critical foundation species in estuaries, providing numerous ecological and economic benefits. However, oyster populations have diminished worldwide. Effective oyster restoration and aquaculture require a mechanistic understanding of the physiological and environmental factors that govern oyster feeding, growth, and resilience under changing coastal conditions. We investigated how oyster ploidy and environmental conditions influenced oyster feeding and investigated how changes in abiotic conditions affected behavioral performance of oyster drills (Stramonita spp.), a key oyster predator. To better understand feeding responses and behaviors of both predator and prey we 1) used in-situ filter feeding assays to determine if feeding …

Enhancing Walleye (Ogaa) Recruitment: Evaluating Assisted Reproduction As A Mitigation Strategy, Douglass Keiser

Biology Graduate Theses

Over the past several decades, cold- and cool-water fish populations across the Upper Midwest, including Minnesota and Wisconsin, have shown troubling signs of decline. Among the most affected is the walleye/Ogaa (Sander vitreus), a species deeply embedded in the ecological balance, cultural identity, and economic vitality of the region, and central to the lifeways, treaty-reserved rights, and resource stewardship of Tribal Nations, including Ojibwe communities across the Upper Midwest. Despite ongoing stocking efforts and harvest regulations, many lake systems have experienced persistent declines in natural recruitment, prompting resource agencies to investigate the underlying causes. One such system is …

Evaluating Management Strategies And Technology To Improve Grazing Efficiency, Thomas E. Aquino

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

Increasing land costs and labor constraints continue to challenge beef producers. More intensive practices can increase harvest efficiency; however, many producers are deterred from implementing them due to increased labor and management considerations. Virtual fencing (VF) may provide a reduced labor alternative to traditional fencing for managing intensive grazing. This dissertation evaluated management strategies and VF technology to improve grazing efficiency of stocker cattle systems. In Experiment 1, VF was used to effectively manage groups of steers grazing in adjacent paddocks separated by only virtual boundaries. There was no difference in VF containment (99%) when steers were grazing co-fenced, with …

Creatures Of Habit? Impact Of Chick Feeder Tray Location On Feed Consumption At 0-7 Days Of Age, Emily Kate Green

Graduate Theses and Dissertations

Early chick nutrition is critical for establishing target growth performance characteristics in broiler chickens. This study evaluated factors within commercial broiler houses that potentially influence feed consumption during the first 7 days. Three trials were conducted in a 12.2 x 122 m commercial broiler house to assess the effects of house sectioning, spatial barriers, and feedline location. In Trial 1, a one-way experimental design was used in which the house was divided into four equal sections using migration fencing every 30.5 m. House sections served as a fixed factor. Feed was provided using chick trays placed beneath the feed line …

Assessing The Potential Of Taming Chicken Gut Commensal Bacteria Using Random Transposon Mutagenesis, Arjun Chapagain

Graduate Theses and Dissertations

The chicken gut microbiome comprises hundreds of bacterial species whose functional roles remain largely unknown, in part because the tools needed to experimentally manipulate these organisms in their native community context have not been systematically developed or validated. This dissertation addresses the gap through three connected research chapters that progressively build a framework for transposon-based genetic delivery in the chicken cecal microbiome, moving from community-wide accessibility mapping to vector optimization to library preparation refinement. In Chapter 2, we established the community-level insertion landscape in chicken cecal metagenome using Himar transposon delivery via RP4 conjugation and aligned Tn-seq reads to a …

Post-Exercise Vitals Recovery Response In Barrel Horses: A Field Study On Cooling Methods Used By Competitors, Lauran E. Hetrick

Electronic Theses and Dissertations

Barrel racing demands peak physical performance from equine athletes, yet limited research evaluates the field-based strategies used to optimize equine recovery at competition. This study assessed recovery management approaches used by competitors to elucidate their influence of physiological recovery by measuring heart rate, respiratory rate, and body temperature during a high-profile barrel race competition. Physiological data were collected at baseline, immediately post-exercise, and during a 15–30-minute cooldown period to characterize recovery under real-world conditions. Significant increases in HR, RR, and BT occurred from baseline to post-run (p < 0.001), followed by reductions during cooldown (p < 0.01), though values remained elevated (p < 0.05). Rinsing reduced HR and RR (p < 0.01), while shade and fans decreased RR and variably influenced HR. Noise, as a confounding variable, decreased HR but increased BT (p < 0.001). Ultimately, these results emphasize multimodal recovery approaches in competitive equine management in the field.

Evaluation Of Palm Oil As An Ingredient In Finishing Beef Cattle Diets On Performance, Carcass Characteristics, And Meat Quality, And The Composition Of Spayed Heifers To Intact Heifers Fed Melengestrol Acetate On Feedlot Performance And Carcass Characteristics, Tate S. Johnson

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

Heifers represent a large proportion of cattle placed in feedlots, making pregnancy management an important consideration for maintaining performance and carcass value. Melengestrol acetate (MGA) is commonly included in feedlot diets to suppress estrus and prevent pregnancy in intact heifers during the finishing period. Alternatively, spaying has historically been utilized as a management practice to allow heifers to graze alongside breeding cattle without the risk of pregnancy. Despite its historical use, there is limited contemporary research comparing the growth performance and carcass characteristics of spayed heifers with intact heifers managed with MGA under modern feedlot conditions. Therefore, a commercial study …

2nd Place Research Paper: Shaping The Ape: Storytelling, Cultural Reflection, And Boundary Negotiation In Human-Ape Zoo Encounters, Abigail Bond Halling

Kevin and Tam Ross Undergraduate Research Prize

The typical Western zoo functions as a unique environment in which animals are frequently positioned as subjects of education and entertainment through the medium of storytelling. In this sense, the zoological institution can also be read as an extension of popular Western constructions surrounding nonhuman animals, particularly those who are symbolically charged characters in our collective imaginary– the great apes. Given the morphological, behavioral, and psychological similarities between humans and other great apes (chimpanzees, gorillas, and orangutans), nonhuman great ape enclosures at the Western zoo become spaces where humans are most radically confronted with navigating the boundaries of the “human-animal …

Impacts Of Supplemental Fat In Finishing Diets On Digestibility, Performance, Carcass Outcomes, Meat Quality And Methane Production Of Feedlot Cattle, Anna Marie Kobza

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

Rising costs and fluctuating availability of supplemental fats has led to increased interest in alternative fat sources or feed additives that might improve utilization of supplemental fat in feedlot diets. Two separate experiments were conducted to evaluate alternative strategies to overcome high fat prices. The first experiment was a metabolism study, conducted to evaluate digestion parameters of supplemental fat sources with or without LYSOFORTE Extend. The objectives of this experiment were to evaluate LYSOFORTE Extend in beef finishing diets containing a saturated fat source (tallow) and unsaturated fat source (corn oil). Duodenally and ruminally fistulated steers were fed diets containing …

Assessment Of Goose-Beaked Whale Responsesto Mid-Frequency Active Sonar Usinga Hierarchical Hidden Markov Model, Stacy L. De Ruiter, Erin A. Falcone, Shannon N. Coates, Brenda K. Rone, David A. Sweeney, Karin A. Dolan, Susan M. Jarvis, Russel D. Andrews, Stephanie L. Watwood, Gregory S. Schorr

University Faculty Publications and Creative Works

Background

Acoustic disturbance is increasingly recognized as an ecological concern, particularly at sea. In light of marine mammal stranding events associated with use of naval mid-frequency active sonar (MFAS), which often involve goose-beaked whales (Ziphius cavirostris), research has sought to detect and characterize Ziphius behavioral responses to MFAS.

Methods

We deployed Sound and Motion Recording and Telemetry (SMRT) tags on 13 Ziphius in the Southern California Bight. The study area includes the United States Navy’s Southern California Anti-submarine Warfare Range (SOAR), and deployments overlapped temporally with training exercises including MFAS use. We used hierarchical hidden Markov models (HHMMs), which provided …

Aggression And Fish Welfare: Challenges And Opportunities, Christine M. Soper, Peter D. Dijkstra

Animal Sentience

Oldfield & Bonano’s (2024) [O&B] target article discusses the wellbeing and sociality of bony fishes. Many fish species, such as cichlids, are not only social but territorial. Aggression is normal, but territorial aggression in a captive environment can have a negative impact on welfare. Aggression-related injuries and deaths are prevalent in pet stores as well as research settings. We discuss the need to develop effective methods to minimize the negative consequences of aggression.

Geographical And Anatomical Microbiome Variation In Invasive Green Iguanas (Iguana Iguana), Amanda A. Diaz

All HCAS Student Capstones, Theses, and Dissertations

The common green iguana (Iguana iguana) was introduced to South Florida in 1965 and has since been an especially pernicious threat both environmentally and economically. This highly invasive species is also expanding in range and populations at an astonishing rate. Understanding how this reptile is able to adapt and thrive in novel environments is of imperative need in order to begin managing their disruptive populations. Notwithstanding their negative impacts and significance, the microbiome of wild populations has not yet been characterized. Here, using 16S ribosomal RNA gene sequencing, this study is the first to characterize the microbiome composition …

An Integrative Description Of Euscorpius Diagorasi Sp. N. From Rhodes, Greece (Scorpiones: Euscorpiidae), Konstantinos Kalaentzis, Francesco Frigioni, Eliza Kaitetzidou, Alessio Iannucci, Alexandros Triantafyllidis

Euscorpius

The genus Euscorpius Thorell, 1876 comprises a diverse and taxonomically challenging group of scorpions in the Mediterranean, with Greece representing one of its principal centers of diversity. In this study, we provide an integrative description of Euscorpius diagorasi sp. n., a new species from Rhodes Island, Greece. The new species is described on the basis of adult male and female morphology and mitochondrial COI sequence data. It is a small oligotrichous species characterized by a total length of approximately 21–25 mm, pale yellow to light brown coloration with darker reddish-brown pedipalps, pectinal tooth count of 8 in the male …