Animal Sciences Commons^™

Environmental Determination Of Gastrointestinal Parasitism In Katahdin Sheep, Brian Arisman

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

Gastrointestinal nematodes (GIN) negatively affect the performance and wellbeing of sheep and are difficult to control due to anthelmintic resistance. Producers are therefore choosing breeds naturally resistant to GIN infection, such as the Katahdin. Katahdin are raised in various climates and management systems in the U.S., and those environmental factors can be combined into eco-management clusters. We hypothesized that GIN challenge varies predictably based on the characteristics of these clusters. Katahdin producers from across the U.S. were surveyed for management information. Body weights (BW), fecal egg counts (FEC) and FAMACHA scores (FAM) were collected on 3,527 Katahdin lambs around 90 …

Evaluation Of Nutritional Factors Affecting Sow Reproductive Longevity, J'Nan E. Wittler

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

Sow reproductive longevity is an important trait for swine operations from a production and economic standpoint. Previous research has shown that a sow needs to produce 3 litters before she covers the costs associated with introducing her to the operation. A literature review of research conducted related to sow longevity is discussed in Chapter 1. Chapters 2 and 3 present data from the University of Nebraska – Lincoln’s long-term sow longevity research. The research looks at the effects of energy restriction with soy hulls during gilt development on sow reproductive longevity through 4 parities. Chapter 2 presents data from replications …

Students' Perceptions Of Online Equine Courses And Their Impacts On Learning Outcomes, Blaire L. (Gibbens) Speck

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

Post-secondary education is always changing and evolving. Over the last few years, significant changes in education have resulted in an increased number of online courses. Approximately 28% of students seeking higher education participate in at least one online course and 14% are enrolled exclusively in distance or online programs (Allen & Seaman, 2016). However, courses that are typically hands-on, like equine science, may be more challenging online. The hands-on experiences in equine science classes help prepare students for future careers. Due to an increase in students choosing to take courses online, a review of online teaching methods was conducted to …

Identifying Early-Life Behavior To Predict Mothering Ability In Swine Utilizing NuTrack System, Savannah Gabrielle Millburn

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

Early recognition of indicator traits for swine reproduction and longevity supports economical selection decision making. Gilt activity is a key variable impacting a sow’s herd life and productivity. The purpose of this study was to examine early- life behaviors contributing to farrowing traits including gestation length (GL), number born alive (NBA), number weaned (NW), and herd life (HL). Herd life was a binary trait representing if a gilt was culled after one parity. Beginning at approximately 20 weeks of age, video recordings were taken on 480 gilts for 7 consecutive days and processed using the NUtrack system. Activity traits …

Evaluation Of The Feeding Value Of Proso Millet In Growing-Finishing Diets For Pigs And Effects Of Feed Ingredients And Medium-Chain Fatty Acids On Porcine Reproductive And Respiratory Syndrome Virus (Prrsv) Survivability, Khang Nguyen

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

The objective of the project were to: 1) evaluate the feeding value of proso millet as a potential substitute for corn in corn-soybean meal-based diets for pigs; and 2) investigate the relationship between feed ingredients and virus survivability, followed by examining feed additive candidates that could mitigate the risk of transmission of viral pathogens.

In Exp. 1, 36 barrows were fed 1 of 4 dietary treatments, including: Diet 1, corn-soybean meal-based (control), and Diets 2, 3, and 4 had proso millet replacing 33%, 67%, and 100% of corn in the control diet, respectively. During Phase 3, pigs consuming the proso …

Impact Of Increasing Level Of Milk Production On Cow And Calf Behavior And Performance In The Nebraska Sandhills, Selby L. Boerman

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

Selection for increased milk production across the United States has resulted in variable cow and calf production responses. Better understanding of calf nursing and grazing behaviors may provide opportunities to help estimate how milk and grazed forage intake influence variability in calf performance. In a 2-yr study, cow-calf pairs (n = 65) were equipped with neck collars containing global positioning system (GPS) units to validate the efficacy of high-frequency GPS data to accurately identify calf nursing events and grazing behavior. Data were collected during 3-wk tracking periods during early lactation (calf age 65.4 ± 10.0 d; EARLY) and late …

Using Strategic Supplementation To Enhance Cow/Calf Productivity In Summer Calving Herds In The Nebraska Sandhills, Nicole M. Woita

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

Young range beef cows consuming low-quality forage may result in an imbalance of energy and metabolizable protein, which can negatively affect the nutrient status of the cow and reproductive performance. In a 2-yr study conducted at Gudmundsen Sandhills Laboratory near Whitman, NE, 2- and 3-yr-old May-calving range cows (n = 181) grazing native range were individually supplemented daily with one of four supplements: 1) mineral with a target intake of 113 g/d (MIN), 2) MIN with 200 mg per head of Rumensin to with a target intake of 113 g/d (RUM), 3) MIN with a 226 g/d of high …

Investigating Bacterial Community Composition And Antimicrobial Resistance Genes In Beef Cattle, Arena E. See

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

While antibiotics have been critical over the last decade for curbing infectious diseases, they have contributed to the rise of antimicrobial resistance (AMR). Infections resulting from antimicrobial-resistant pathogens are correlated with severe morbidity, mortality, and healthcare costs. With the increasing concerns regarding AMR and its emergence, it is paramount to understand not only the effects of antibiotics on microbial community and diversity, but also to develop a novel tool that gives us a better understanding of the spread and functional traits of AMR genes.

To this end, rumen, fecal, and pen surface samples were collected from 72 animals at United …

The Impact Of Steam-Flaked Rye Replacing Steam-Flaked Corn On Performance And Carcass Characteristics Of Yearling Steers And The Effect Of Exogenous Megasphaera Elsdenii Administration Techniques On Ruminal Fermentation And Blood Parameters In An Acidosis Challenge Model, Samantha K. Wagner

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

A feedlot study was conducted to evaluate the effects of replacing steam-flaked corn (SFC) with steam-flaked rye (SFR) in the diets of yearling steers (Exp. 1). A separate study was conducted to evaluate the effects of three different administration techniques of Megasphaera elsdenii NCIMB 41125 on rumen fermentation and blood parameters in an acidosis challenge model (Exp. 2). In Exp. 1, SFC was replaced with SFR to create four different treatments, each differing in the ratio of SFC:SFR. The four treatments were 0:100, 25:75, 50:50, and 100:0 SFR:SFC (as a percentage of the grain inclusion). Increasing inclusions of SFR resulted …

Targeting Inflammation In Heat-Stressed Wethers Improves Growth And Efficiency And Alters Body Composition: A Brief Exploration And Application Of Extension Principles, Micah Samuel Most

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

The objective of our first study was to determine how administering anti-inflammatory dexamethasone and ω-3 polyunsaturated fatty acid (PUFA)-rich fish oil affects growth efficiency and body composition in heat-stressed finishing lambs. Commercial wethers were randomly assigned to be fed under heat stress (35-40 ℃) or thermoneutral (19 ℃, n = 10) conditions for 30 d, and controls were pair-fed to eliminate differential feed intake. Heat-stressed wethers were randomly assigned to receive clinical-dose dexamethasone IM injections every 72 h, twice daily fish oil capsule oral boluses, or placebos. Heat stress decreased (P < 0.05) growth and efficiency, but dexamethasone and fish oil supplementation recovered these performance measures. Heat stress also decreased (P < 0.05) predictive body composition metrics that were at least partially improved by administration of dexamethasone and fish oil. Proximate analyses of muscles showed that heat stress decreased (P < 0.05) percentage of protein and increased (P < 0.05) percentage of intramuscular fat, neither of which was improved by dexamethasone or fish oil. Immunohistochemistry revealed that heat stress decreased (P < 0.05) myoblast differentiation and muscle fiber size, but anti-inflammatory supplementation recovered differentiation only. Plasma IGF-1 concentrations were not different among groups throughout the study. These findings demonstrate how heat stress-induced inflammation contributes to impaired growth, efficiency, and body composition observed in heat-stressed feeder lambs. However, targeting inflammation with dexamethasone or fish oil recovers many of these deficits.

The Cooperative …

Evaluation Of Corn Processing Method And Sweet Bran Inclusion On Beef Cattle Performance And Nutrient Digestion And Individual Sweet Bran Components On Nutrient Digestion, Rebecca L. Sjostrand

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

One feedlot trial (Exp. 1) and one digestion trial (Exp. 2) were conducted to evaluate the interaction of corn processing method and Sweet Bran inclusion on nutrient digestion, ruminal fermentation parameters, and feedlot performance. In Exp. 1 when no Sweet Bran was fed, cattle fed steam-flaked corn (SFC) had greater ADG, HCW and a 12.4% improvement in feed efficiency compared to cattle fed a high-moisture corn/ dry-rolled corn (HMC/DRC) blend. However, as Sweet Bran increased in the diet to 40%, cattle fed HMC/DRC had greater improvements in ADG and HCW than cattle fed SFC resulting in similar performance at 40% …

The Impact Of Plant Cell Wall Lignin On Energy Utilization In Lactating Jersey Cows, Jason D. Stypinski

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

Fiber from forages comprises a significant proportion of dairy cattle rations and by extension, it contributes largely to the energy concentration of the diet. While the proportion of fiber in the diet is important, the composition of fiber is probably more important as the different constituents of this fraction vary in their contributions to the nutritive value of the feed. Lignin has been described as an important factor limiting the digestion of NDF, reducing intake, and compromising milk production. Although lignin’s effects on these responses have been well characterized, the literature lacks data on the use of indirect calorimetry to …

Annotating Gene Expression And Regulatory Elements In Tissues From Healthy Thoroughbred Horses And Identifying Candidate Mutations Associated With Perosomus Elumbis In An Angus Calf, Alexa Mckenna Barber

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

Genome annotation has a direct impact on the success of genomic studies. Transcriptome analyses and chromatin immunoprecipitation and sequencing (ChIP-seq) have been used to functionally annotate genomes. These methods can identify protein-coding genes, non-coding transcripts, and cis-regulatory elements across the genome. The primary objective of the first study was to functionally annotate the equine genome through the assessment of nine tissues: adipose, brain, heart, lamina, liver, lung, skeletal, muscle, testis, and ovary. In the first project, 150 bp, paired-end RNA sequencing (RNA-seq) libraries were generated in stallion tissues and compared to previously generated mare RNA-seq libraries to quantify variation in …

Greenhouse Gas Emissions From Two Contrasting Beef Systems From Birth To Slaughter In Eastern Nebraska, Levi J. Mcphillips

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

Over the last 15 years, the increase in land use for corn and soybean has come at the expense of acres of grasslands and perennial forages employed in conventional beef-production systems. Implementing alternative cow-calf production systems into existing cropping systems may be a solution for reduced land availability and reducing total greenhouse gas emissions (GHG). Therefore, GHG from a conventional (CONV) pasture-based cattle production system with cows wintered on corn residue and summer grazing of brome pasture were compared to partial-confinement system (ALT) with cows and calves in a drylot during the summer and grazing cover crops and corn residue …

Small Grain Cereal Cover Crops For Late Fall Or Early Spring Grazing, Kallie J. Calus

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

Beef cattle operations are confronted with early spring and late fall forage deficiencies. Producers in integrated crop and livestock systems can fill forage gaps using cover crops as a forage source in between cash crops.

A five-year study evaluating forage production, growing calf performance and economics of grazing an oats cover crop planted after corn silage (CS) and high moisture corn (HMC) corn harvests was conducted. The economic analysis accounted for costs of establishing and grazing the oats and the value of calf gain to determine fall grazing system profitability. Steers had greater average daily gain grazing oats after CS …

Management Of Late Summer Planted Annual Forages For Grazing And The Impacts Of Novel Sweet Bran Plus Products On Performance And Carcass Characteristics Of Beef Finishing Steers, Devin Anthony Jakub

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

Two separate grazing studies were conducted to evaluate: 1) the effects of rapeseed inclusion into late summer planted oats on the performance of growing steers during late fall and winter (Exp. 1) and 2) the effects of forage allocation on forage utilization and performance of steers grazing a late summer planted oat-rapeseed mix (Exp. 2). Variation in the corn wet milling process can result in negative effects on animal performance, nonetheless, there remains interest in further exploration and refinement of corn wet milling byproducts to achieve optimal byproduct compositions and cattle performance. Thus, another experiment was conducted to evaluate the …

Impact Of Wood-Sourced Biochar On Carbon And Nitrogen Capture In Beef Feedlot Systems, Jessica L. Sperber

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

A feedlot growing and finishing experiment evaluated the effect of including pine-sourced biochar at 0.8 (growing) and 1.0% (finishing) of dietary DM on steer performance, carcass characteristics, and greenhouse gas (GHG) production (Exp 1). Two nutrient mass balance experiments were conducted during winter and summer seasons to evaluate the effect of spreading unprocessed red cedar biochar on the feedlot pen surface on manure nutrient capture and cattle performance (Exp 2). In Exp. 1, the inclusion of biochar in the growing diet did not impact steer performance. The inclusion of biochar in the finishing diet significantly reduced intake and gain, resulting …

Utilizing Online Resources To Enhance Distribution Of Competitive Animal Evaluation Knowledge And Benefits, Brooke L. Parrish

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

In recent years, the shift toward online education has revealed new challenges for learners to retain information, and for educators to find new and engaging ways to present content. This mixed methods, action research study explores the need and creation of online resources for competitive horse judging through surveys and pilot groups. The study was broken into four cycles. The first was an adult learner analysis survey, distributed through email Listservs and extension social media pages, to aid in answering the research questions: what expert horse judging instructors indicate their students should be learning, and what resources they need. Based …

Evaluation Of Cattle Management For Systems With Limited Perennial Pasture, Morgan Grabau

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

Due to the conversion of perennial pasture and hay land to cropland in the western corn belt region, alternative methods of cow/calf management are being used to decrease reliance on perennial forages. These include grazing corn residue and feeding cow/calf pairs in confinement. Previous research has shown that limit-feeding a diet of low-quality forage and energy-dense co-products to cows in confinement is cost-effective. However, this strategy may limit the intake of the young calf and thus their performance. A study was conducted to evaluate the impacts of two alternative calf management strategies when pairs are in confinement, early weaning or …

Feeding A New Corn Milling Coproduct To Lactating Dairy Cattle: Examination Of Whole Animal Energy And Nitrogen Balance, Addison Lee Carroll

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

New coproducts are continually developed in the ethanol production industry. With that, the new product originates from the dry milling process which is unlike the traditional process as nitrogenous based particles are concentrated from the residual fiber by sieving post fermentation. Although high protein coproducts have been available since the mid 2000’s. These new products must be evaluated for chemical composition so that they can be accurately described in feed libraries that are used in commercial ration formulation software. While chemical composition provides us an initial and useful description of a feed product, in vivo nitrogen and energy balance studies …

Host Genetics And Phenotype Associations Within The Bovine Rumen Microbiome, Waseem Abbas

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

Rumen microbes have a symbiotic relationship with the host where the host provides a suitable environment and microbial fermentation fulfill nearly 70% of the energy needs of the host. Rumen microbes play a central role in host performance and health. To date, most rumen microbiome studies have focused on the influence of diet on microbial species composition. In addition to dietary factors, studies have suggested that host genetic markers could influence the colonization of gastrointestinal microbiota. However, our understanding of the host-microbiome interaction and how host phenotype is influenced by the rumen microbiome is limited. This dissertation demonstrates: (1) host …

The Effects Of Omega-3 Pufa Infusions During Late Gestation On Developmental Pathologies In The Intrauterine Growth Restricted Fetus, Taylor A. Lacey

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

Low birthweight due to intrauterine growth restriction is associated with metabolic disorders after birth. Our 1^st study assessed deficits in skeletal muscle glucose metabolism and pancreatic β cell function in IUGR fetal sheep. We aimed to evaluate the effectiveness of daily intravenous infusions of the anti-inflammatory ω-3 polyunsaturated fatty acid (PUFA), eicosapentaenoic acid (EPA), as a means of improving deficits previously observed in the IUGR fetus by targeting fetal systemic inflammation. The presence of systemic inflammation in IUGR fetuses was evident by increased total circulating populations of total leukocytes, lymphocytes, and monocytes. However, these were …

The Role Of Fatty Acids In Ruminant Diets And Novel Feed Ingredients High In Omega-3 Fatty Acids Fed In Feedlot Diets, Mitchell M. Norman

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

A finishing study evaluated the performance, carcass characteristics and fatty acid profiles of steers fed four inclusions of a novel feedstuff Green Grass. Green Grass is a product comprised of sesame meal, giant kelp, cassava, and sorghum containing high concentrations of polyunsaturated fatty acids. No differences were observed in initial BW, final BW, BW gain, HCW, LM area, 12^th rib fat depth, calculated YG, or liver abscess %. Dry matter intake linearly increased as Green Grass inclusion increased in the diet. Steers fed Green Grass had lower G:F than control cattle, and steers fed 30% Green Grass had a …

Low-Oxygen Dry Aging Of Beef, Joseph A. Sonderman

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

The objective of this research project was to determine the effects of removing oxygen from the beef dry aging process. Boneless upper 2/3 Choice beef strip loins (n = 18) were randomly assigned to three aging treatments: wet aging, traditional (aerobic) dry aging, and low-oxygen dry aging. All treatments were aged for 41 days at 2 ± 1°C. The dry-aged treatments were held at 50% relative humidity (RH) with a fan speed of 2,200 revolutions per minute (RPM). Low-oxygen dry-aged samples were aged in chambers housed within an oxygen impermeable film bubble. After aging, yield was determined for the …

Estimation Of Breed Effects And Genetic Parameters For Age At Slaughter And Days To Finish In A Multibreed Beef Cattle Population, Lindsay Rae Upperman

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

Cattle efficiency during the finishing phase is a crucial factor in determining profit in the beef cattle industry. Economically relevant traits associated with efficient production include age at slaughter (AAS) and days to finish (DtF). Selection to reduce the number of days an animal takes to reach a finish endpoint would ultimately reduce production costs, increase net profits, and result in a more sustainable production system. However, most harvested animals are from commercial herds, necessitating the use of indicator traits from seedstock animals for selection. Potential indicator traits include ultrasound measurements that could be genetically correlated to DtF traits. The …

Enhancement Of Dry-Aged Beef Quality By Dietary Supplementation Of High Levels Of Vitamin E, David Manuel Velazco Marroquin

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

Crossbred cattle (n = 150; 10/pen) were grain-finished with the dietary addition of 2,200 international units of vitamin E (α-tocopherol) per head per day for 100 days. One low-Choice carcass (n = 12) was selected, and strip loins were collected. Low Choice control carcasses (n = 12) were randomly selected from commercial, fed-cattle production to serve as controls. Strip loins were randomly assigned to wet or dry aging for 42 days. On day 42, control dry-aged and control wet-aged loins had the highest TBARS values and vitamin E wet and dry-aged loins had lower TBARS values ( …

Quantification And Repeated Measurements Of Conformation Traits In Replacement Females To Optimize Sow Longevity, Melanie D. Trenhaile Grannemann

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

The objectives were to 1) assess the reliability of objective conformation trait measurements between evaluators, 2) evaluate effects of dietary energy and lysine during development and housing system during first gestation on longevity, reproductive performance, and conformation, 3) characterize conformation changes throughout life, 4) identify phenotypic associations between conformation and longevity, 5) estimate heritability of conformation traits, and 6) assess genetic relationships between conformation traits measured throughout life in sows. Sows (n = 622) were fed a standard, energy restricted, or standard energy with increased lysine diet during gilt development and housed in either a group pen or stall …

The Effect Of Heat Stress And Beta-Adrenergic Agonists On Fatty Acid Mobilization And Their Individual And Interacting Impact On The Adipose Transcriptome Of Ruminant Livestock, Rachel R. Reith

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

Heat stress reduces livestock efficiency, induces inflammation, and alters adipose tissue metabolism through stress-induced epinephrine acting on beta-adrenoreceptors (β-AR). Supplementation of beta-adrenergic agonists (β-AA) improve livestock growth and carcass traits, also by acting on β-AR located in skeletal muscle and adipose tissue. The binding of β-AR in adipose tissue results in changes in adipose tissue metabolism including increased lipolysis and decreased fatty acid synthesis. Due to their similar effects on stress response pathways, the possible interaction of heat stress and β-AA could negatively impact animal well-being. The purpose of the first study was to understand how ractopamine (RAC), a beta-one …

Evaluation Of Grain Type And Processing Method On Steer Performance, Carcass Characteristics, And Nutrient Digestion, Caitlin A. Coulson

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

A feedlot finishing study evaluated the effect of replacing corn with dry-rolled wheat in diets containing wet distillers grains plus solubles (WDGS; Exp 1). Two studies were conducted to evaluate the effect of corn type [dry corn (DC), high-moisture corn (HMC), or a blend of dry and high-moisture corn (BLEND)] processed with either AutomaticRoller Mill (ROLL) or hammer mill (HAMMER) on steer performance, carcass traits, and nutrient digestibility (Exp. 2 and 3). In Exp. 1, steers were fed diets containing 100% dry-rolled corn (DRC) or a 50:50 blend of dry-rolled corn and wheat (WHEAT) in diets containing 12 …

Understanding Rumen Microbial Community Structure And Function Towards Decreasing Methane Emissions, Allison L. Knoell

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

Resource use is continually being limited due to this growth, therefore, production of high-quality animal protein sources, such as meat and milk, are challenged. The rumen microbiome is extensive and serves to provide several metabolic requirements for the animal for growth. Recently, a significant amount of research is being driven towards understanding the rumen microbiome due to its large effect on metabolic requirements.

A study was conducted to replace alfalfa with nonforage fiber sources in dairy cows. It was determined milk yield and intake are maintained when nonforage fibers replace forage sources, while decreasing methane levels. Water consumption decreased when …