Animal Sciences Commons^™

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 …

An Empirical Study On The Economic And Policy Drivers Of Livestock Risk Protection Utilization, Milan Chauhan

Department of Agricultural Economics: Dissertations, Theses, and Student Research

Federally supported risk management programs for livestock producers have existed for the last twenty years. Among these, Livestock Risk Protection (LRP) is a federally subsidized insurance tool available for cattle producers to manage downside price risk. In recent years, participation in LRP has surged. This paper examines the key economic and policy variables that partially drive LRP utilization and analyzes the role of risk management educational efforts in the decision to participate and the intensity of the insurance utilization using unique state-level panel data from 2003 through 2023.

The study analyzes three complementary metrics of insurance utilization: market volume (policies …

Walleye And Sauger Movement And Entrainment In Lewis And Clark Lake, William Joseph Radigan

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

Walleye Sander vitreus and Sauger Sander canadensis are both socioeconomically important sportfish species in Lewis and Clark Lake, an interjurisdictionally managed mainstem Missouri River reservoir fishery. Since 2011, adult catch per unit effort (CPUE) of both Walleye and Sauger has remained at approximately 50% of pre-2011 levels. A presumed reason for the suppressed CPUE of adult Walleye and Sauger is substantial entrainment of larval and adult fish resulting from the reservoir’s high turnover rate (7.2 d). Acoustic telemetry was used to quantify adult movement and entrainment and ichthyoplankton trawls were used to assess larval entrainment. Relative importance of factors driving …

Environmental Effects On Preweaning Calf Health, Lindsay L. Waechter-Mead

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

Neonatal calf health is an important factor in the productivity and profitability in the beef cattle industry, influencing preweaning survival, growth, and long-term performance. The overall objective of this thesis is to characterize risk factors that contribute to health issues in young beef calves. The first objective is to review literature exploring the environmental factors affecting preweaning morbidity and mortality, including hypothermia, precipitation, and wind. Management strategies such as the effect of environmental conditions of calving location, body condition score in dams at parturition, and the impacts of dystocia on calf health will also be discussed. Gaps in current research …

Heterotopias Of Confinement: Zoo Architecture And The Loss Of Elephant Agency, Clayton Gill Beasley

Electronic Theses and Dissertations

Zoos functions as a site where human-animal relationships are structured through built environments that mediate control and representation. This study examines zoos as heterotopias—spaces where power and surveillance are negotiated between human observers and captive nonhuman animals. While zoos are often framed as spaces of conservation and education, their architectural design reinforces hierarchies of observation and confinement, shaping both human perceptions of nature and the lived experiences of nonhuman animals. This research focuses on Asian elephants as a critical species within this framework, exploring how their captivity illuminates tensions between human-imposed structures and nonhuman autonomy. Drawing from theories of heterotopia, …

Epidemiological Inferences Of The Impacts Of Winter Ticks On Moose Health, Krishna S. Woerheide

Department of Entomology: Dissertations, Theses, and Student Research

The North American Moose (mooz in Anishinaabemowin, Ojibwe language, Alces alces), a culturally significant subsistence species for the Anishinaabe people, faces population decline due to calf predation, pathogen transmission, and parasitism by the winter tick (Dermacentor albipictus), all exacerbated by climate change. This study explores the impact of winter tick infestations on moose health, with a focus on natural mineral seeps as potential transmission hotspots in moose habitats within the Grand Portage Indian Reservation (Gichi Onigaming), on Isle Royale National Park (Minong), and within the 1854 Ceded Territory (greater northeastern Minnesota) - ancestral and present homelands of …

Ediacaran Paleocommunity Structure, Body Size Evolution, And The Rise Of Complex Animals, Matthew Philip Craffey

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

The Ediacaran period (635-538ma) is a key interval in the evolution of life as it records the first macroscopic animal communities. Major extinction pulses appear to have altered the composition of the global marine biosphere between each sub-interval of the Ediacaran Period: the Avalon, White Sea, and Nama assemblage Zones. While considerable attention has been paid to the causes of these extinction pulses, less has been afforded to the consequences of Ediacaran biotic turnover for community organization and function. Moreover, it is unclear how body size - the defining trait of macrofauna - affected the transition between animal groups across …

Spatial Ecology And Predator–Prey Interactions Of Mountain Lions In California's San Francisco North Bay, Jacob A. Harvey

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

Understanding spatial ecology and predator-prey interactions are central to wildlife ecology and conservation. We tracked mountain lions with GPS telemetry to evaluate space use, predator-prey interactions, and resource selection in California’s San Francisco North Bay, USA. In Chapter 1, we evaluated the influence of human disturbance on home range size, prey composition, and kill rates on black-tailed deer (Odocoileus hemionus columbianus) across an urban-rural gradient. Both males and females increased home range size with increasing development at low to moderate levels of development, but female home range size stabilized across greater proportions of development while male home range …

Assessment Of Sampling Gears For Bigheaded Carp In Mid-Order Prairie Rivers In Nebraska, Brett M. Anderson

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

Silver Carp Hypophthalmichthys molitrix and Bighead Carp H. nobilis (collectively bigheaded carp) have invaded tributaries to the Missouri River and Platte River in Nebraska, USA. Information pertaining to efficient sampling protocols for assessing bigheaded carp populations as well as benefiting removal efforts is needed. Herding is a method used to increase the capture efficiency and detection probability of adult bigheaded carp by simultaneously using active and passive sampling gears. During June-July 2023, four herding techniques were assessed regarding their ability to elicit directional movement past an enclosure gate. The combination of sound and electrofishing resulted in the highest mean …

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 …

The Influence Of Solar Energy Infrastructure On Pollinators And Crops, Deisy Garcia

Theses and Dissertations

As the human population grows, demand for agriculture and renewable energy rises. Landuse competition is caused by the expansion of area-intensive solar photovoltaic (PV) facilities. While solar energy is crucial to mitigate climate change, it presents challenges related to land availability and effects on habitats for essential pollinators. In Chapter II, a spatial analysis was conducted to examine the relationship between solar panel density and pollinator diversity, exploring regions with the least interaction between these two factors. Our findings can inform solar siting and management strategies at landscape levels, in conjunction with field studies, that both mitigate potential interaction and …

A Comparative Study Of Urban And Natural Nesting Gray Hawks In The Lower Rio Grande Valley Of South Texas, Evan Farese

Theses and Dissertations

Urbanization can negatively impact birds of prey, which occupy higher trophic levels. The Gray Hawk (Buteo plagiatus) is a neotropical raptor inhabiting the Lower Rio Grande Valley (LRGV) of Texas, where it is threatened. The species’ ecology has been little studied and it is unclear how urbanization may affect population viability. I studied Gray Hawk reproductive success, diet, and thermal ecology at nests in urban and natural habitats in the LRGV. Camera trap data showed adults at urban nests delivered mostly avian prey, while mammalian prey was most frequently brought to natural nests. Data from temperature loggers showed …

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 …

First Specimen-Based Record Of Barbonymus Schwanefeldii (Bleeker, 1854) (Teleostei: Cyprinidae) From Laguna De Bay, Philippines, Kent Elson S. Sorgon, Marjorie Juliana L. Martinez, Andrei Justin F. So, Mariko Franccesca R. Aboganda, Jazreen Nicole G. Parungo, Aeris Johanne G. Poricallan, Keona Tiffany B. Prieto, Mellissa Jewel S. Magday, Alexa Charlize Dc Geronimo, Ma. Vianca Julia E. Anupol, Derreck O. De Leon

Biology Faculty Publications

The introduction of non-native fish species in the freshwater ecosystems of the Philippines presents a clear threat to native ichthyofauna, making verified reports of such introductions all the more critical. Through the examination of a collected specimen and anecdotes from fisherfolk and social media, we present here the first records of the occurrence of the tinfoil barb, Barbonymus schwanefeldii (Bleeker, 1854), in Laguna de Bay, Luzon Island, Philippines. This represents the addition of another non-native fish species in this lake, which is increasingly becoming dominated by non-native and invasive fishes that have been intentionally or accidentally introduced. Monitoring landed fish …

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 …

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 …

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 …