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The Extraction And Chemical Characterization Of The Avian Pigments Turacin And Turacoverdin, Sarah R. Bekkali

Honors Scholar Theses

Bird coloration is a trait that extends beyond mere aesthetics as it has an extensive range of biological significance. Plumage patterns and hues can influence camouflage, mate choice, social dominance, and physiological performance. Bird fitness, their ability to survive and reproduce, is greatly dependent on color. Melanins, carotenoids, and pterins are well-studied pigment systems that are commonly found across many avian species’. Alternatively, porphyrin-based pigments are rare and less-studied as they only found in turacos a sub-Saharan African bird belonging to the family Musophagidae. This thesis focuses on two pigments of interest: turacin, the deep crimson-red pigment found in …

Effects Of Melatonin Supplementation On Exercise Induced Stress In Horses, Hannah Clark Valigura

Theses and Dissertations

Exercise is a necessary component of athletic conditioning but imposes substantial physiological stress on horses, resulting in oxidative stress, inflammation, muscle damage, and thermal strain that can impair performance and recovery. Melatonin, a neurohormone with potent antioxidant and thermoregulatory properties, has been proposed as a novel nutritional strategy to mitigate these effects. This dissertation aimed to (1) characterize serum melatonin concentrations following oral supplementation, (2) evaluate the effects of melatonin on oxidative stress, inflammation, and muscle damage biomarkers after exercise, and (3) examine its influence on physiological parameters during exercise under warm weather conditions. Across a series of controlled experiments …

Effect Of Accelerated Adaptation Programs On Feedlot Performance And Health Of Steers Drenched With Megasphaera Elsdenii And Quantifying And Partitioning Multi-Year Carbon Dioxide And Methane Fluxes In A Grazed Temperate Pasture, Rebecca Mcdermott

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

With strong consumer demand for beef and increasing concern about the environmental impacts of beef production, improving production efficiency and advancing the understanding of the environmental footprint are critical for the long-term sustainability of beef production systems. The first experiment evaluated the effect of accelerated adaptation strategies, using energy intake and cattle behavior, on feedlot performance, carcass characteristics, and health of yearling steers drenched with exogenous Megasphaera elsdenii. Accelerated adaptation programs (0, 7, or 14 d transition to 100% finisher) were compared to a traditional 21-d adaptation. Dry matter intake responded quadratically across treatments, with the greatest intake observed in …

Investigating The Effects Of Stress On The Passive Transfer Of Antibodies From Colostrum To The Newborn Calf, Audrey F. Dykes

Animal Science Undergraduate Honors Theses

The objective of the current study was to examine passive transfer of immunoglobulins A (IgA) and G (IgG) to the calf in relation to dam’s fecal cortisol and lactoferrin. In July 2024, late-gestation, Angus crossbred heifers pregnant by artificial insemination (n = 30) were moved to the University of Arkansas Division of Agriculture Stocker Unit and housed in 0.42-ha grass paddocks for each heifer. Calving began in mid-August. Heifers were observed routinely throughout the workday and then at 8 p.m., 12 a.m., and 6 a.m. After calving, the calf was allowed to stand and suckle once then dam sample collection …

Assessing The Impact Of Toxic Fescue Consumption During Gestation On Muscle Growth Gene Expression And Beef Color Quality Of The Offspring, Madison Blank

Animal Science Undergraduate Honors Theses

Endophyte-infected tall, toxic fescue is the most common forage for beef cattle in the southeastern U.S. However, exposure to this forage causes detrimental effects on the health of gestating cattle. The exposure to toxic fescue during gestation has been shown to impact fetal development during pregnancy and their offspring’s subsequent growth. However, limited information is currently available on the impact of this exposure on the meat quality of the offspring. Our objective is to determine how the dam’s exposure to toxic fescue during gestation impacts the beef color and quality of the final offspring.

A total of 22 animals (11 …

The Evaluation Of Broiler Lines Divergently Selected For Water Conversion Ratio Under Acute And Chronic Stress, Baileigh B. Cash

Poultry Science Undergraduate Honors Theses

            The importance of water conversion ratio in broiler production influences not only bird physiology but also barn environment, litter quality, and provides potential solutions to environmental stressors. However, very little is known about how genetic selection for water conversion ratio can affect litter characteristics and performance parameters, specifically under heat stress conditions. This study evaluates the effects of genetic lines, environmental conditions, and time, on litter and bird performance characteristics in high water conversion ratio (HWCR) and low water conversion ratio (LWCR) broilers. Litter samples were collected from HWCR and LWCR broilers raised under heat-stress and thermal-neutral conditions, both before …

Effect Of 1,25(Oh)₂D₃ Glycoside Supplementation Duration On Bacterial Chondronecrosis With Osteomyelitis (Bco) Lameness In Broilers, Zoe R. Zeman

Animal Science Undergraduate Honors Theses

Bacterial chondronecrosis with osteomyelitis (BCO) is a significant cause of lameness in commercial broilers, resulting in substantial animal welfare concerns and economic losses. This study evaluated the effect of 1,25(OH)₂D₃ glycoside supplementation duration on the incidence of BCO-related lameness in broilers. Cobb surplus male broiler chicks were assigned to four treatment groups: a wire-flooring positive control, a litter-flooring negative control, and two treatment groups on litter flooring receiving 1 μg 1,25(OH)₂D₃ as glycosides supplementation per kg diet for either 14 or 28 days. Lameness incidence was recorded from day 22 through day 56, and all lame birds were evaluated for …

Effect Of A Probiotic Microbial Gel Jointly With Two Versions Of Supplemental Direct-Fed Microbials In Receiving Cattle Diets On Growth Performance And Health, John Mitchell

Biological Sciences Undergraduate Honors Theses

The objective was to assess the effect of a probiotic microbial gel (BIOFRESH® Microbial Gel, Agrarian Solutions) administered on arrival in combination with feeding one of two different direct-fed microbials (DFM 365a or DFM 365b, Agrarian Solutions) on the health and growth performance of stocker calves at high risk for bovine respiratory disease (BRD). Beef heifer calves (n = 292, BW = 476 ± 5 lb) arriving on 3 separate receiving dates were used in the 42-day receiving study. On arrival (d -1), heifers were processed, stratified by d -1 body weight, and then assigned randomly to 9 pens (10 …

The Effects Of Heat Stress On White Blood Cell Profiles And Antibody Concentrations In Broilers Genetically Selected For Low Water Conversion Ratio Compared To The Modern Random Bred Broiler, Luke B. Janski

Poultry Science Undergraduate Honors Theses

Heat stress (HS) is one of the most significant environmental stressors impacting poultry production worldwide, reducing growth, feed efficiency, welfare, and immune competence. With global temperatures rising, understanding physiological and immunological adaptations to HS is essential for sustainable production. Broiler chickens selectively bred for low water conversion ratio (LWCR) have shown potential for reduced water consumption under environmental challenges; however, their immune resilience under HS conditions compared with modern random-bred (MRB) broilers remains unclear. This study investigated the effects of cyclic HS on red- (RBC) and white- (WBC) blood cells and humoral immunity in LWCR and MRB broilers. Birds were …

A Series Of Investigations On The L. Cornutus Host System And Bivesiculid Sp. Cercariae, Briana K. Zaffiro

All HCAS Student Capstones, Theses, and Dissertations

Rising global temperatures are likely modulating parasite-host interactions, yet the direction and magnitude of these changes remain uncertain. Rarely are these interactions viewed from both a host and parasite perspective. Using both CT_max, or Critical Thermal Maximum, and Clark-type polarographic oxygen microelectrodes, the physiological metabolic effects are investigated. CT_max is examined in Common Shiners, Luxilis cornutus, and is shown to be modulated by parasitism: uninfected fish had the highest CT_max average of 37.0°C, whereas heavily infected fish had decreased CT_max averaging 35°C. Prior to the parasite metabolic investigation, a suitable medium was determined, as …

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 …

The Effect Of Including A Yeast Culture Containing Essential Oils In Receiving Cattle Diets On Growth Performance And Health, Taylor Deanna Foster

Animal Science Undergraduate Honors Theses

Due to the increased risk of bacterial populations developing resistance to current antibiotics, consumer perceptions surrounding the utilization of antibiotics use in cattle, and the endemic incidence of bovine respiratory disease (BRD) among growing and finishing cattle, alternative management strategies to improve the health of cattle must be developed. The objective of this study was to evaluate the use of a supplement containing a yeast culture and an essential oils blend (YEO) on the health and growth performance of stocker calves at high-risk for BRD. Crossbred male beef calves (n = 185) received on two separate dates were used in …

Influence Of Increased Supplementation Of Organic-Complexed Zinc To Beef Cows During Gestation: Effects On Preweaning Health Of Offspring, Naija N. Sharpley

Animal Science Undergraduate Honors Theses

The objective of this study was to determine the effect of increasing zinc supplementation from organic-complexed sources to beef cows during gestation on calf performance. In May 2025, during gestation, Angus crossbred cows were confirmed pregnant with female sexed semen (n = 83) and enrolled in the current study. Cows (4.7 ± 2 years of age and 531 ± 84.4 kg body weight, mean ± standard deviation) were allotted to 4 groups (20 to 21 cows/group) based on, sire of heifer calf, cow age, and cow body weights taken at weaning. Assigned groups received 1 of 2 treatments (2 groups/treatment): …

Sorghum Grain Secondary Metabolites And Underlying Genetics To Reduce Foodborne Pathogens In Poultry, Maria A. Conti

All Dissertations

The rise in antibiotic-resistant pathogens poses a threat to the poultry industry's ability to maintain animal health, prompting growing interest in alternatives to synthetic antibiotics. The use of non-tannin sorghum [Sorghum bicolor (L.) Moench] in poultry rations offers a valuable alternative, as this cereal grain has a high bioactive profile that can provide health benefits, including antimicrobial (AM) activity. The scope of this study was to examine the AM potential of non-tannin sorghum grain against Clostridium perfringens, a major foodborne pathogen that negatively impacts poultry health and production. To that end, the inhibitory effects of a non-tannin sorghum …

Improving Genomic Prediction For Feed Efficiency Traits In Beef Cattle Using Microbiome As An Intermediate Omics, Egodage Bhagya Sewwandi Samarakoon

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

Feed efficiency traits, including feed conversion ratio (FCR), average daily gain (ADG), and average daily dry matter intake (ADDMI), are economically important in beef cattle production. Emerging evidence suggests that host genetics influences feed efficiency traits through the microbiome. This study evaluates the integration of microbiome data as an intermediate layer in the Neural Network Mixed Model (NNMM), which hierarchically models genotype–microbiome–phenotype relationships as a unified regulatory network to improve genomic prediction accuracy. To reduce the computational burden of NNMM, microbiome features dimension were reduced using principal component analysis (PCA) and direct feature selection of top-ranked open reading frames (ORFs) …

The Detection Of Morbidity Using A Remote Sensing Ear Tag On Newly Received Steers And Feedlot Performance And The Effects Of Feeding Experior And Optaflexx On Carcass Characteristics And Meat Tenderness In Beef Steers, Lauryn O. Smidt

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

Two experiments were conducted to evaluate the effects of remote sensing health technology and growth-promoting feed additives on feedlot cattle performance, health outcomes, and carcass characteristics. In the first study, 638 crossbred steers (initial BW = 270 kg; SD = 18.6 kg) were used in a randomized block design to assess the effectiveness of a remote sensing ear tag (RST; HerdDogg, Seward, Nebraska) versus conventional pen-rider observation (PR) for detecting morbidity during a 35-d receiving period and subsequent 180-d finishing period. No differences were detected between PR and TAG for ending BW, average daily gain (ADG), dry matter intake (DMI), …

Carcass Mass And Cooling Dynamics As Determinants Of Beef Color, Tenderness, And Dark-Cutting Risk, Grace C. Johnson

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

Discoloration in beef has important implications to the beef industry. Dark-cutting (DC) beef remains one of the most economically significant color defects; however, industry prevalence has only marginally declined (≈ 0.1%) despite mitigation efforts. This lack of improvement largely stems from research focused on pre-harvest stress and glycogen depletion leading to dark, firm, and dry (DFD) beef. However, not all darkcutting beef originates from DFD phenotypes. Atypical dark-cutting (ATDC) phenotypes have recently been observed and do not exhibit the classic metabolic indicators of DFD. This trend coincides with steadily increasing carcass weights in the beef industry and raises the possibility …

Monitoring Biodiversity Growth In An Oyster Reef Restoration: Understanding How Oyster Reef Life Cycle May Impact Biodiversity., Gabriel A. Roses

Theses and Dissertations

Oyster reefs are vital to marine ecosystem health, improving water quality and providing food and habitat for diverse species. We assessed biodiversity changes for a proposed oyster reef restoration site to help guide management, future assessment, and deepen understanding of how oyster reefs function and their ecosystems dynamics.

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 …

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 …

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 …

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 …

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 …

The Influence Of Additional Zinc Supplementation During Gestation On The Trace Mineral Concentrations Of Tissues, Milk, And Calf Serum At Birth, Hunter Miller

Animal Science Undergraduate Honors Theses

Minerals are known to play a key role in the immune system, growth, and development of animals. An important part of a calf's life is receiving colostrum immediately after birth, which provides the calf with immunoglobulins and necessary nutrients that are required. Furthermore, the gestation period is another very important aspect of the calf's life where they can take in the necessary nutrition. This study compared how two different supplements fed during the gestation period ultimately affected the mineral concentrations of the colostrum, placenta, calf plasma, and cow liver. The supplements that were provided were a 1) control that provided …

The Effect Of Blue-Green Light On Behavioral Repertoire And Fear Responses In Broiler Chickens, Addie Walker

Animal Science Undergraduate Honors Theses

The broiler chicken industry has increased the number of birds produced each year,

making the mitigation of stressors that affect broiler health and meat quality increasingly

important. New management strategies, like lighting protocols, could help combat stressors and

promote behavioral indicators of positive welfare. This study compared the effects of blue-green

and white light on broiler fear response using a tonic immobility test and behavioral repertoire in

the home pen using continuous focal sampling. Day-of-hatch male broiler chicks (N=600) were

randomly divided into 12 pens (n=50 chicks/pen). The pens had either a white LED light

(control, n=6) or a blue-green …

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 …