Animal Sciences Commons^™

Changes In Whole Blood Parameters In Beef Heifers May Contribute To Delayed Pubertal Attainment, Jessica A. Keane

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

Pubertal development in beef heifers is a transient period that has many contributing factors. Previously in our lab, progesterone (P4) concentrations collected from heifers at weaning (Oct) to breeding (May) were used to identify four distinct pubertal groups: Typical, Early, Start-Stop, and Non-Cycling. There is limited research on heifers and the impacts of whole blood cell populations, particularly WBCs, during pubertal development; however, girls with differing puberty onset displayed altered concentrations of hematocrit, white blood cells (WBC), and hemoglobin concentrations. Thus, our hypothesis was that heifer pubertal groups with delayed or precocious puberty may have increased white blood cells or …

Variation In The Genome And Transcriptome Associated With Beef Cattle Production And Investigation Of The Metabolic Consequences Of Beta-Adrenergic Agonist Supplementation, Renae L. Sieck

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

Beta-adrenergic agonists (β-AA) are widely used supplements in livestock production to improve feed efficiency and increase lean muscle mass. Heat stress is one of the largest economic burdens to the livestock industry due to production efficiency losses and morbidity and mortality of animals. Both β-AA and catecholamines released in response to heat stress bind to β-adrenoceptors on the skeletal muscle cell surface to activate downstream signaling pathways. The purpose of this study was to determine if β-AA supplementation and heat stress have an additive effect on the skeletal muscle transcriptome. 3’ RNA sequencing of samples of the longissimus dorsi was …

The Effects Of Different Feed Supplements On Performance Parameters, Egg Measurements, And Eggshell Integrity In Older White Leghorn Laying Hens, Josephine N. Foley

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

Two studies were conducted to evaluate the efficacy of multiple feed additives on the performance of older White Leghorn hens. Study 1 examined the effects of 2 vitamin/mineral supplements and 1 medium chain fatty acid. Study 2 examined the effects of a novel butyric acid product, a tributyrin ester. Both studies followed a completely randomized design with repeated measures and data were analyzed using the Glimmix procedure in SAS version 9.4 for Windows.

The first study took place November 2015 to April 2016. Trt 1 was a control diet, Trt 2 was supplemented with a Ca, Fe, Mn, Cu, Zn …

Evaluation Of Condensed Algal Residue Solubles As An Ingredient In Cattle Finishing Diets And Its Effects On Digestibility And Fatty Acid Flow And A Comparison Of Single And Dual Implant Strategies In Finishing Heifers, John Calvin Gibbons

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

Two experiments, a performance study (Exp. 1) and digestion study (Exp. 2) were conducted to evaluate a novel liquid feed, condensed algal residue solubles (CARS), in feedlot diets. In Exp. 1 and Exp. 2, steers were fed three inclusions of CARS at 0%, 2.5%, 5%. There were quadratic responses for greater carcass adjusted final BW, ADG, G:F, HCW, 12^th rib fat, and yield grade. There was a linear increase in marbling score and a linear decrease in DMI and LM area as CARS increased. In Exp. 2, CARS did not affect intake or digestibility. Fatty acid flow at the …

Interaction Of Urea With Frequency And Amount Of Distillers' Grains Supplementation For Growing Steers On A High Forage Diet, Haley F. Linder

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

Two studies were conducted to determine interactions of urea inclusion to a dried distillers grains plus solubles (DDGS) supplement fed at two amounts and two frequencies to steers on a high forage diet. In Exp. 1, 120 steers were fed individually for 84 d. Steers received ad libitum grass hay and 1 of 8 treatments. Supplement was fed either every day (D) or 3x/week (ALT), amount of supplement fed was 6.36 kg/week (LO) or 12.73 kg/week (HI), and contain either no urea (-U) or 1.3% urea (+U). Hay DMI and steer BW were measured. In Exp. 2, 8 ruminally cannulated …

Improving The Accuracy Of Genomic Predictions: Investigation Of Training Methods And Data Pooling, Johnna Lynn Baller

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

One of the primary factors in the response to selection is the accuracy of selection. This study focused on methodologies to predict breeding values (BV) accurately within multi- and single-step genomic evaluations. Factors including cross-validation methods, dependent variables, and genotyping strategies were assessed on the accuracy of genomic BV while using multi-step prediction in real and simulated data. In both cases, random clustering led to largest estimated accuracies compared to clusters based on k-means, k-medoids, and principle component analysis, but differences in bias were not detected. Using deregressed estimated BV (EBV) to estimate SNP effects led to larger accuracies and …

Energy Metabolism In Jersey Cows: Improving Our Understanding Of Energy Requirements And Utilization, Dennis Morris

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

Energy is the most limiting nutrient for high producing lactating dairy cows and improving our understand of factors affecting energy supply should improve our ability to estimate net energy of lactation (NE_L), milk production, and tissue accretion. To achieve this object, firstly, three experiments were completed to determine 1) maintenance energy requirements; 2) factors affecting heat production; and 3) the relationship between urinary N and energy excretion. Three additional experiments using lactating Jersey cows were completed to evaluate energy utilization of diets varying in 1) supply of Lys and His; 2) fatty acids (FA) and …

Characterization Of Protein And Fat In Dairy Feeds And Implications On Digestibility And Milk Composition, Kassidy Kate Buse

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

A variety of feedstuffs are used to comprise dairy rations, each with their own nutritional contributions. In order to best utilize these feedstuffs to maximize production, characterization of their chemical composition is needed. Through the use of both in vitro and in situ methods, not only can the composition of the feed be determined, but also its digestibility. Also, because of the important role they play in human health, omega 3 fatty acids have received increasing attention. Most individuals consuming Western diets do not meet the recommended requirement for omega 3 fatty acids, and one way to improve that is …

Advancing The Science Of Dry-Aged Beef, Felipe Azevedo Ribeiro

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

In order to tightly control dry aging environmental conditions, we designed and built a computerized dry aging system that is capable of measuring and precisely controlling relative humidity (RH; ± 1%), temperature (± 0.5 °C), air flow (± 0.015m³/min), and mass loss (± 5 g). This dissertation addressed the effects of RH and ultimate pH on meat quality and sensory attributes of dry-aged beef. In study one, we learned that wet-aged steaks had higher L* (P = 0.01), a* (P = 0.03), and b* values (P < 0.001), lower discoloration scores (P < 0.05), and lower TBARS (thiobarbituric acid reactive substance) values (P = 0.03) than dry-aged treatments. Under prolonged …

Influence Of Strategic Supplementation And Genetic Potential For Milk Yield On Forage Digestibility, Amino Acid Utilization, And Livestock Production, Tasha M. King

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

When consuming low-quality forages or at times when nutrient demands are high, ruminants may be unable to meet these requirements resulting in a state of negative energy balance. With feed costs contributing a large portion of production costs, providing dietary nutrients to maintain energy balance must be done so strategically. Additionally, producers must ensure consistent reproductive performance and offspring weaned to maintain a successful livestock enterprise. The objective of these studies was to evaluate the effect of glucogenic precursor supplementation and milk yield on forage digestibility, amino acid utilization, and livestock production. In experiment 1, a metabolism study was conducted …

Effects Of Ndf Digestibility On Lactating Jersey Cows: Observed And Modeled Performance, Kirby Craig Krogstad

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

Improving the digestibility of fiber and our understanding of how to feed it will optimize the ruminants’ niche in our society, which is to convert human inedible products to high quality protein in the form of meat and milk. Neutral detergent fiber (NDF) digestibility has been studied and modeled for decades, but it is increasingly important as livestock production is scrutinized for resource use and sustainability. Increasing the amount of NDF fed and improving models of NDF digestibility will improve sustainability by increasing the precision at which we feed livestock which results in less nutrient and greenhouse gas (GHG) emissions. …

The Role Of Postnatal Adrenergic Manipulation In The Mediation Of Fetal Programming Adaptions In Growth And Skeletal Muscle Glucose Metabolism That Persist In The Juvenile Iugr-Born Lamb, Rachel L. Gibbs

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

Our 1^st study assessed growth deficits in IUGR juvenile lambs and the benefits of treatment with adrenergic and inflammatory mediators. Growth metrics including bodyweight, rate of gain, and crown-rump length were diminished by placental insufficiency-induced IUGR through 2 mo. of age but were recovered by daily clenbuterol or curcumin supplementation. Body composition metrics indicated by bioelectrical impedance, proximate analysis, and loin size revealed that fat-free lean mass, specific muscle group sizes, and protein-to-fat ratios were reduced in unsupplemented IUGR lambs but recovered to or even past controls in clenbuterol-supplemented lambs. From these findings, we conclude that IUGR impairs postnatal …

Translational Genomics For Improving Sow Fertility, Hiruni R. Wijesena

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

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

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

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

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

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

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

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

Energy And Amino Acid Metabolism In Lactating Jersey Cows Consuming Feed Byproducts, Kyle Alvin Mclain

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

Animal protein byproducts are high bypass proteins commonly used in the dairy industry. These bypass proteins can escape the rumen to supply additional amino acids needed to support milk and protein yield. Two of the more popular animal protein byproducts used in the dairy industry are blood meal and hydrolyzed feather meal. In the first experiment, two flow meters were compared using headbox-style calorimeters. The objectives of the first study were to test mass flow meter (MFM) and volumetric flow meter (VFM) by measuring O₂ consumption and CO₂ production and to illustrate the effects of incomplete gas recovery …

Impact Of Diet And Quality Grade On Meat Quality Characteristics And Their Relationship To Oxidative Stress, Nicolas A. Bland

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

Marbling and tenderness in meat are some of the most impactful factors for the consumer eating experience. The cause of the relationship between marbling and tenderness is still unresolved. This study was conducted to evaluate the effects of feeding different types of processed corn, with or without distiller grains on oxidative stress, and how that relates to tenderness and shelf life of beef steaks of differing quality grades. Steers (n = 240) were finished on dry rolled corn (DRC), DRC + 30% dried distillers grains (DDGS), steam flaked corn (SFC), or SFC + 30% DDGS. Cattle were fed 10 …

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

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

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

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

Evaluation Of Maternal Diet And Its Effect On Milk Composition And Piglet Health And Growth Performance, Shana Marie Barnett

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

Both graduate research and graduate teaching duties work together to help to develop a graduate student’s skills both in the classroom and on their research experiments. Being both a GTA and GRA allows a student to form more sound hypotheses, connect better with students, and better understand their own research.

During the time as a GTA and GRA four surveys were developed to analyze different groups of students and their learning environment and two animal experiments were conducted to evaluate maternal diet and its effect on milk composition and piglet health and growth performance.

The surveys given to students consisted …

Investigating Microbiomes And Developing Direct-Fed Microbials To Improve Cattle Health, Alison C. Bartenslager

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

Over the last decade, global beef production has increased to meet the protein needs of the growing population. As a result, the intensification of beef cattle production systems has resulted in broad spectrum prophylactic use of antibiotics and growth promoting agents. With increased concern around antimicrobial resistance (AMR) and emergence of novel pathogenic strains of bacteria, it is critical to understand disease progression and associated changes in the microbiome to develop novel therapeutic alternatives to reduce antibiotic use and control disease. One such approach that is currently being investigated is the development of novel direct-fed microbial strains to outcompete pathogens …

Heat Stress-Induced Deficits In Growth, Metabolic Efficiency, And Cardiovascular Function Coincided With Chronic Systemic Inflammation And Hypercatecholaminemia In Ractopamine-Supplemented Feedlot Lambs: Atypical Cyclicity At Puberty In Beef Cows Is Associated With Early Deficits In Muscling, Metabolic Indicators, And Myoblast Function In Offspring But Does Not Impact Feedlot Performance, Rebecca M. Swanson

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

Our 1^st study evaluated the effects of b-adrenergic agonist (ractopamine) supplementation on growth, health, and wellbeing in heat-stressed feedlot wethers. Chronic heat stress impaired growth, metabolism, and wellbeing even when the impact of reduced feed intake was eliminated by pair-feeding. We observed systemic inflammation and hypercatecholaminemia that were likely mediators of these deficits. Moreover, ractopamine did not diminish any wellbeing indicators and improved muscle growth without worsening the effects of heat stress.

Our 2^nd study assessed the effects of pubertal cyclicity (weaning to 1^st breeding) in cows on myoblast-mediated muscle growth, metabolism, and growth efficiency of their …

Comparison Of Comprehensive Health Score In North American Housed Giraffe And Free-Ranging Giraffe From South Africa, Haley Beer

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

Stress is evident in many animal species and has been correlated to disease prevalence. During stressful events, allostasis is initiated by physiologic systems to maintain or reestablish homeostasis to protect an organism’s viability. Over time, the acclimation to frequent stress causes systematic dysregulation, leading to the phenomena of increased allostatic load. Allostatic load has been assessed in animal species via serum through selection of representative, multi-system biomarker indices. Perception and number of stress events may impact dysregulation severity, yielding allostatic load as a predictive tool. However, the allostatic load methodology poses application limitations to individuals without historical data and those …

Evaluation Of Protein Sources And Holstein Finishing Systems For Organic Beef Production And A Comparison Of Single And Dual Implant Strategies In Finishing Heifers, Elizabeth A. Schumacher

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

Two in situ experiments were conducted to compare the rumen undegradable protein content (RUP) and RUP digestibility of conventional and organic field peas, fish meal, dehydrated alfalfa, and soybean meal. Significant differences were detected between feed samples in both studies for all variables measured. Variation existed between sample types but the data did not suggest that organic and conventional feeds are different when processed with the same methods. A performance experiment was conducted utilizing individually fed Holstein steers comparing the effect of RUP source in a simulated organic production system. Dietary treatments were: no supplemental protein (NONE), field peas (FP), …

Impact Of Myoglobin Oxygenation State On Color Stability Of Beef Steaks During Frozen Storage And Thawed Retail Display, Morgan Lee Henriott

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

Meat color is the most important product characteristic that impacts consumer purchasing decisions. Therefore, the major objectives of this thesis were to determine the impact of myoglobin oxygenation level and frozen storage duration on both frozen and thawed beef color. USDA Choice strip loins (n = 36) were aged for 4 d or 20 d and cut into steaks. Steaks were randomly assigned to a myoglobin oxygenation level [deoxymyoglobin (DeOxy; immediately packaged), oxygenation (Oxy; oxygenated in air for 30 minutes), or high oxygenation (HiOxy; packaged for 24 h in 80% O₂)]. Steaks were then vacuum packaged in …

Impact Of Feeding Distillers Grains Or Isolated Components In Distillers' Grains To Growing And Finishing Cattle, And The Comparison Of Protein Content And In-Situ Digestibility Of Feeds Commonly Used In Feedlot Diets, Brianna B. Conroy

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

The use of distillers' grains originating from biofuel production has become widely used in feedlot diets. Distillers' grains has been identified as having an increased feeding value relative to dry-rolled corn, in recent years the composition of distillers' grains has begun to change due to greater refinement in the ethanol production process. Two feedlot trials were conducted to evaluate the contribution of fat, fiber, and protein from distillers' grains in the diets of growing and finishing cattle. Growing steers were fed a grass hay-based ration, including a corn control diet compared to a diet containing modified distillers' grains plus solubles, …

Effects Of Late Gestation Supplementation And Creep Feeding On Spring Calving Beef Cows In The Nebraska Sandhills, Devin Lynn Broadhead

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

The objectives of this research were to 1) evaluate the effects of late gestation supplementation, synchronization and creep feeding on cow and calf production traits 2) evaluate the pooled effects of 5 studies involving late gestation supplementation on cow and calf traits. Experiment 1 was a three year study conducted on 8 pastures at the Gudmundsen Sandhills Laboratory. Cows were assigned to 1 of 4 late-gestation supplementation treatments, postpartum progestin or control, and 1 of 2 creep feed treatments to make up a 4 x 2 x 2 factorial arrangement. Calves were followed through to slaughter.

Experiment 2 involved 5 …

Effects Of Alternative Carbohydrate Sources And Soybean-Derived Isoflavones On The Microbiome And Immune System Of Nursery Piglets And Intestinal Porcine Epithelial Cell Line J-2, Sydney Kinstler

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

Four experiments were conducted to characterize the microbiome of the piglet and observe effects of diet on growth performance and immunity. In Exp. 1, 96 nursery piglets were fed varying carbohydrate sources and in Exp. 2, 64 piglets were fed a soy protein concentrate or soybean meal as-is or supplemented with an isoflavone concentrate. Body and feeder weights were measured for growth performance estimation. Luminal contents and scrapings were isolated for microbial composition analysis. Fecal and blood samples were extracted in Exp. 2 for microbiome and immunity analysis. Diets did not affect growth performance (P > 0.10); however, Exp. 1 …

Evaluation Of Alpha Amylase Containing Corn On Beef Cattle Performance And Digestibility And Double-Cropped Annual Forages Following Corn Harvest, Mckenna Brinton

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

One digestion and three feedlot trials evaluated the effect of a new corn hybrid containing an α-amylase enzyme trait, Syngenta Enogen Feed Corn (SYT-EFC) on site and extent of digestion, ruminal fermentation parameters, and feedlot performance. Experiments utilized corn containing the enzymatic gene (SYT-EFC) compared to commercially available corn (CON), processed as corn silage (CS) kernel processed or not (KP), dry-rolled corn (DRC), high-moisture corn (HMC), or a blend of DRC and HMC. Growing calves fed high inclusions of CS, displayed increased G:F when CS was KP, resulting in a 6.5% improvement in G:F. Hybrid and kernel processing did not …

Impact Of Beta-Adrenergic Agonist Supplementation And Heat Stress On The Microbiome And Gastrointestinal Transcriptome Of Sheep, Erin Margaret Duffy

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

Improving animal growth and efficiency are critical points of research as the world’s population and demand for agriculture products increase. Therefore, adaptions or changes in the gut are of interest to maximize growth efficiency and wellbeing of livestock. The gastrointestinal tract of the rumen plays many critical roles with the assistance of the associated microbial community. One way to improve animal performance is supplementation of β-adrenergic agonists (β-AA) which are commonly fed to cattle during the last 20-40 days of the finishing period, improving muscle growth by decreasing adipose deposition and increasing muscle accretion. Two β-AA, Ractopamine HCl (β1-AA) and …

Undergraduate Success In Animal Science Courses Based On Demographics, Motivation, And Online Courses, Haylee Anne Lavoie

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

A deeper understanding of student demographics, motivation, and outlook of online vs. face to face courses in Animal Science is needed to allow educators to facilitate greater student success. The purpose of this study was to investigate student factors which effected their final grades. The following courses were surveyed at the University of Nebraska- Lincoln Animal Science Department: Animal Products (ASCI 210), Anatomy and Physiology of Domestic Animals (ASCI 240), Introduction to Companion Animals (ASCI 251), Companion Animal Behavior (ASCI 271), Companion Animal Nutrition (ASCI 321), Equine. Nutrition (ASCI 322), Equine Reproduction (ASCI 342), Animal Welfare (ASCI 370), Processed Meats …