Animal Sciences Commons^™

Effect Of Dietary Urea In Gestating Beef Cows: Circulating Metabolites, Morphometrics, And Mammary Secretions, Ligia D. Prezotto, Jennifer F. Thorson

Department of Animal Science: Faculty Publications

Prolific use of supplementation strategies, including the utilization of urea, are practiced in beef cattle production systems. Unfortunately, the influence of urea supplementation on metabolics, adipose tissue mobilization, and mammary secretions is limited in beef cows. Therefore, the objectives of this experiment were to assess the influence of urea supplementation on metabolic profiles, morphometrics, and mammary secretions. Pregnant, multiparous beef cows were fed individually and assigned to treatment (n = 4/treatment) as Control or Urea Supplementation. Blood samples and body weight were collected every 28 d throughout gestation. Backfat thickness was measured via ultrasonography on days 28 and 280 of …

Effect Of Dietary Urea In Gestating Beef Cows: Circulating Metabolites, Morphometrics, And Mammary Secretions, Ligia D. Prezotto, Jennifer E. Thorson

Department of Animal Science: Faculty Publications

Prolific use of supplementation strategies, including the utilization of urea, are practiced in beef cattle production systems. Unfortunately, the influence of urea supplementation on metabolics, adipose tissue mobilization, and mammary secretions is limited in beef cows. Therefore, the objectives of this experiment were to assess the influence of urea supplementation on metabolic profiles, morphometrics, and mammary secretions. Pregnant, multiparous beef cows were fed individually and assigned to treatment (n = 4/treatment) as Control or Urea Supplementation. Blood samples and body weight were collected every 28 d throughout gestation. Backfat thickness was measured via ultrasonography on days 28 and 280 of …

Use Of High-Pressure Processing To Improve The Redness Of Dark-Cutting Beef, Cole Reesman, Gary Sullivan, Mary-Grace C. Danao, Morgan Pfeiffer, Sunil More, Gretchen G. Mafi, Ranjith Ramanathan

Department of Animal Science: Faculty Publications

The objective was to evaluate the effects of high-pressure processing (HPP) levels on retail color of dark-cutting beef. Eight USDA Choice (mean pH = 5.5; normal-pH beef) and 12 dark-cutting (mean pH = 6.3) strip loins were obtained from a commercial packing plant within 2 d of harvest. Dark-cutting loins were cut into equal sections, vacuum packaged, and randomly assigned to 0 (no HPP), 300, 450, and 600 MPa of pressure for 90 s using chilled water. Following 48 h of dark storage at 2°C, dark-cutting loin sections were cut into 1.9-cm-thick steaks, placed in Styrofoam trays overwrapped in polyvinyl …

The Effect Of Spirulina Platensis Algae Inclusion In Feed Of Commercial Broilers Subjected To Cyclic Heat Stress, Kirsten Shafer

Graduate Theses and Dissertations

The effect of Spirulina platensis inclusion in feed of commercial broilers was evaluated over one experiment. The study aimed to investigate the effects of Spirulina platensis freshwater algae inclusion on live performance and processing characteristics of commercial broilers subjected to daily cyclic heat stress. Day old Ross 708 male broilers were placed into 8 environmentally controlled chambers. At d 21, four chambers remained on a control diet containing no algae (CON) while 4 chambers received a diet that included algae at an inclusion rate of 2.5% (ALG). An 8 hour daily cyclic heat stress (24°C to 36°C) was applied to …

Evaluation Of The Effects Of Pine-Sourced Biochar On Cattle Performance And Methane And Carbon Dioxide Production From Growing And Finishing Steers, J. L. Sperber, B. C. Troyer, Galen E. Erickson, Andrea K. Watson

Department of Animal Science: Faculty Publications

A feedlot growing (77-d) and finishing (111-d) experiment was conducted to evaluate the effects of feeding biochar on steer performance, methane and carbon dioxide emissions, and carcass characteristics. Two treatments were evaluated, a control diet without biochar and the same diet with biochar included at 0.8% of dietary DM (growing) or 1.0% of dietary DM (finishing). The growing diet consisted of 40% corn silage, 40% wheat straw, 15% modified distillers grains plus solubles, and 5% supplement, with 0.8% biochar replacing fine ground corn in supplement. The finishing diet consisted of 55% high-moisture corn (HMC), 35% Sweet Bran, 5% wheat straw, …

Assessment Of United States Department Of Agriculture Food Safety Inspection Service Humane Handling Enforcement Actions: 2018–2020, Karly N. Anderson, Ashlynn A. Kirk, Kurt D. Vogel

Department of Animal Science: Faculty Publications

Federally inspected slaughter establishments in the United States must adhere to the Humane Methods of Slaughter Act and regulations that enforce it. Failure to comply with this law results in a Humane Handling Enforcement Action (HHEA) issued by the United States Department of Agriculture Food Safety Inspection Service (USDA FSIS). The objective of this study was to systematically analyze and describe HHEAs issued between 2018 and 2020. Enforcement action notification letters were accessed from the USDA FSIS website and date, location, regulatory action, reason for noncompliance, species, and follow up action for each HHEA was recorded. …

Assessment Of United States Department Of Agriculture Food Safety Inspection Service Humane Handling Enforcement Actions: 2018–2020, Karly N. Anderson, Ashlynn A. Kirk, Kurt D. Vogel

Department of Animal Science: Faculty Publications

Federally inspected slaughter establishments in the United States must adhere to the Humane Methods of Slaughter Act and regulations that enforce it. Failure to comply with this law results in a Humane Handling Enforcement Action (HHEA) issued by the United States Department of Agriculture Food Safety Inspection Service (USDA FSIS). The objective of this study was to systematically analyze and describe HHEAs issued between 2018 and 2020. Enforcement action notification letters were accessed from the USDA FSIS website and date, location, regulatory action, reason for noncompliance, species, and follow up action for each HHEA was recorded. …

Epidemiological Aspects Of Equid Herpesvirus-Associated Myeloencephalopathy (Ehm) Outbreaks, Eva Klouth, Yury Zablotski, Jessica L. Petersen, Marco De Bruijin, Gittan Gröndahl, Susanne Müller, Lutz S. Goehring

Department of Animal Science: Faculty Publications

: Equid Herpesvirus Myeloencephalopathy (EHM) is a multifactorial disease following an EHV-1 infection in Equidae. We investigated a total of 589 horses on 13 premises in Europe in search of risk factors for the development of EHM. We found that fever (p < 0.001), increasing age (p = 0.032), and female sex (p = 0.042) were risk factors for EHM in a logistic mixed model. Some breeds had a decreased risk to develop EHM compared to others (Shetland and Welsh ponies; p = 0.017; p = 0.031), and fewer EHV-1-vaccinated horses were affected by EHM compared to unvaccinated horses (p = …

Inactivation Of Salmonella In Nonintact Beef During Low-Temperature Sous Vide Cooking, Heather B. Hunt, Samuel C. Watson, Byron D. Chaves, Gary Sullivan

Department of Animal Science: Faculty Publications

Sous vide cooking is a method of food preparation in which food is vacuum sealed and cooked in a water bath that is set to a precise temperature and circulated by a sous vide device. Due to ease of use and affordability, this cooking method has grown increasingly popular in food service kitchens and domestic settings. However, low‐temperature, long holding time sous vide cooking recommendations from manufacturers and chefs in popular press raise food safety concerns – specifically those for the preparation of nonintact beef products. The objective of this experiment was to address these concerns by validating a 5 …

Evaluation Of Growth Performance, Carcass Characteristics, And Methane And Co2 Emissions Of Growing And Finishing Cattle Raised In Extensive Or Partial-Intensive Cow-Calf Production Systems, Zachary E. Carlson, Levi J. Mcphillips, Rick R. Stowell, Galen E. Erickson, Mary E. Drewnoski, Jim C. Macdonald

Department of Animal Science: Faculty Publications

An experiment was conducted over 2 yr to measure performance and greenhouse gas (GHG) emissions of weaned calves from two cow-calf production systems. Crossbred steers and heifers (n = 270, initial body weight (BW) = 207 kg, SD = 35) were used in a randomized complete block design, with treatments applied to the cow-calf system. Treatments were: 1) a traditional system consisting of April to June calving with smooth bromegrass pasture and grazed corn residue as forage resources (TRAD); 2) an alternative system consisting of July to September calving utilizing partial-drylot feeding, summer-planted oats, and corn residue grazing (ALT). …

The Effect Of Corn Silage Hybrid And Inclusion On Performance Of Finishing Steers And Silage Hybrid Effects On Digestibility And Performance Of Growing Steers, F. Henry Hilscher, Curt J. Bittner, Jana L. Gramkow, Melissa L. Jollyy-Breithaupt, Mitch M. Norman, Hannah C. Wilson, Andrea K. Watson, James C. Macdonald, John N. Anderson, Galen E. Erickson

Department of Animal Science: Faculty Publications

Three experiments evaluated the effects of three corn silage hybrids, inclusion, and nutrient digestibility in growing and finishing diets. The three hybrids tested included a control (CON), a hybrid containing a brown midrib (bm3) trait (BM3), and an experimental bm3 hybrid with the soft endosperm trait (BM3-SOFT). Experiment 1 utilized 360 crossbred steers (body weight [BW] = 334; SD = 25 kg) to evaluate inclusion of silage in a finishing diet at (15% or 45% of diet dry matter [DM]) and silage hybrid (CON, BM3, or BM3-SOFT). Experiment 2 and 3 utilized 216 crossbred steers (BW = 324; SD = …

Design And Development Of A Broiler Mortality Removal Robot, Guoming Li, Gary Daniel Chesser, Joseph L. Purswell, Christopher L. Magee, Richard S. Gates, Yijie Xiong

Department of Animal Science: Faculty Publications

Manual collection of broiler mortality is time-consuming, unpleasant, and laborious. The objectives of this research were: (1) to design and fabricate a broiler mortality removal robot from commercially available components to automatically collect dead birds; (2) to compare and evaluate deep learning models and image processing algorithms for detecting and locating dead birds; and (3) to examine detection and mortality pickup performance of the robot under different light intensities. The robot consisted of a two-finger gripper, a robot arm, a camera mounted on the robot’s arm, and a computer controller. The robot arm was mounted on a table, and 64 …

The Effects Of Administering Different Metaphylactic Antimicrobials On Growth Performance And Health Outcomes Of High-Risk, Newly Received Feedlot Steers, Carley M. Coppin, Taylor M. Smock, Cory L. Helmuth, Jeff L. Manahan, Nathan S. Long, Ashley A. Hoffman, Jeffery A. Carroll, Paul R. Broadway, Nicole C. Burdick Sanchez, James E. Wells, Samodha C. Fernando, Kristin E. Hales

Department of Animal Science: Faculty Publications

Bovine respiratory disease (BRD) is the primary animal health concern facing feedlot producers. Many antimicrobial mitigation strategies are available, but few studies have compared feedlot performance during both the receiving and finishing periods following application of different antimicrobials used as metaphylaxis at arrival. The objective of this study was to compare antimicrobial metaphylaxis methods on clinical health and growth performance across both the receiving and finishing periods. A total of 238 multiple-sourced steers in two source blocks were used in a generalized complete block design. The four treatments included: 1) a negative control, 5 mL of sterile saline injected subcutaneously …

The Effect Of Infection Risk On Female Blood Transcriptomics, Brenna M. G. Gormally, Patricia C. Lopes

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Defenses against pathogens can take on many forms. For instance, behavioral avoidance of diseased conspecifics is widely documented. Interactions with these infectious conspecifics can also, however, lead to physiological changes in uninfected animals, an effect that is much less well understood. These changes in behavior and physiology are particularly important to study in a reproductive context, where they can impact reproductive decisions and offspring quality. Here, we studied how an acute (3 h) exposure to an immune-challenged male affected female blood transcriptomics and behavior. We predicted that females paired with immune-challenged males would reduce eating and drinking behaviors (as avoidance …

Tree To Tree: Phylogenetics Of Diverse Anura Using Portable Lab Equipment: Primer Optimization, Bioinformatic Pipeline, And Phylogenetic Analyses Reveal Potential New Species And Ability To Identify Evolutionary Relationships In A Hyper Diverse Anura Clade Using Nanopore Sequencing, Elinor Sterner

Independent Study Project (ISP) Collection

The Corredor Llanganates-Sangay is an extremely significant region for conservation, coined a “gift to the earth” by the World Wildlife Fund. Understanding amphibians species and populations is key due to their roles as hyper sensitive bioindicators. In recent years, portable sequencing equipment (Mini PCR thermocyclers, Oxford Nanopore Technology’s MinION sequencer, etc) make genetic data collection in remote areas possible, greatly increasing potential for conservation genetics and genomics. This study uses portable equipment to sequence two mitochondrial loci in 104 Anuran samples collected in four sites in the Corridor and presents phylogenies of each gene as well as a concatenated phylogeny. …

Evaluation Of The Effects Of Wood-Sourced Biochar As A Feedlot Pen Surface Amendment On Manure Nutrient Capture, Jessica L. Sperber, Galen E. Erickson, Andrea K. Watson

Department of Animal Science: Faculty Publications

Feedstuffs utilized in U.S. feedlot finishing rations incorporate high concentrations of N and P, with less than 15% of fed N and P retained by the animal. The remaining N and P are excreted in the manure, where the opportunity for manure N loss via ammonia (NH3) volatilization from the feedlot pen surface is a risk to the environment and lowers the value of manure as a fertilizer. Two nutrient mass balance experiments were conducted during the winter and summer seasons to evaluate the effects of spreading unprocessed Eastern red cedar biochar onto the feedlot pen surface on manure nutrient …

Type 2 Polysaccharide Storage Myopathy In Quarter Horses Is A Novel Glycogen Storage Disease Causing Exertional Rhabdomyolysis, Stephanie J. Valberg, Zoë J. Williams, Carrie J. Finno, Abigail Schultz, Deborah Velez-Irizarry, Marisa L. Henry, Keri Gardner, Jessica Lynn Petersen

Department of Animal Science: Faculty Publications

Background: Both type 1 (PSSM1) and type 2 polysaccharide storage myopathy (PSSM2) are characterised by aggregates of abnormal polysaccharide in skeletal muscle. Whereas the genetic basis for PSSM1 is known (R309H GYS1), the cause of PSSM2 in Quarter Horses (PSSM2-QH) is unknown and glycogen concentrations not defined.

Objectives: To characterise the histopathological and biochemical features of PSSM2-QH and determine if an associated monogenic variant exists in genes known to cause glycogenosis.

Study design: Retrospective case control.

Methods: Sixty-four PSSM2-QH, 30 PSSM1-QH and 185 control-QH were identified from a biopsy repository and clinical data, histopathology scores …

Vitamin And Mineral Supplementation And Rate Of Weight Gain During The First Trimester Of Gestation In Beef Heifers Alters The Fetal Liver Amino Acid, Carbohydrate, And Energy Profile At Day 83 Of Gestation, Matthew S. Crouse, Kacie L. Mccarthy, Ana Clara B. Menezes, Cierrah J. Kassetas, Friederike Baumgaertner, James D. Kirsch, Sheri Dorsam, Tammi L. Neville, Alison K. Ward, Pawel P. Borowicz, Lawrence P. Reynolds, Kevin K. Sedivec, J. Chris Forcherio, Ronald Scott, Joel S. Caton, Carl R. Dahlen

Department of Animal Science: Faculty Publications

The objective of this study was to evaluate the effects of feeding heifers a vitamin and mineral supplement and targeting divergent rates of weight gain during early gestation on the fetal liver amino acid, carbohydrate, and energy profile at d 83 of gestation. Seventy-two crossbred Angus heifers were randomly assigned in a 2 × 2 factorial arrangement to one of four treatments comprising the main effects of vitamin and mineral supplementation (VTM or NOVTM) and feeding to achieve different rates of weight gain (low gain [LG] 0.28 kg/day vs. moderate gain [MG] 0.79 kg/day). Thirty-five gestating heifers with female fetuses …

Vitamin And Mineral Supplementation And Rate Of Gain In Beef Heifers Ii: Effects On Concentration Of Trace Minerals In Maternal Liver And Fetal Liver, Muscle, Allantoic, And Amniotic Fluids At Day 83 Of Gestation, Kacie L. Mccarthy, Ana Clara Ana, Cierrah J. Kassetas, Friederike Baumgaertner, James D. Kirsch, Sheri T. Dorsam, Tammi L. Neville, Alison K. Ward, Pawel P. Borowicz, Lawrence P. Reynolds, Kevin K. Sedivec, J. Chris Forcherio, Ronald Scott, Joel S. Caton, Carl R. Dahlen, Kacie L. Mccarthy

Department of Animal Science: Faculty Publications

We evaluated the effects of vitamin and mineral supplementation (from pre-breeding to day 83 of gestation) and two rates of gain (from breeding to day 83 of gestation) on trace mineral concentrations in maternal and fetal liver, fetal muscle, and allantoic (ALF) and amniotic (AMF) fluids. Crossbred Angus heifers (n = 35; BW = 359.5 ± 7.1 kg) were randomly assigned to one of two vitamin and mineral supplementation treatments (VMSUP; supplemented (VTM) vs. unsupplemented (NoVTM)). The VMSUP factor was initiated 71 to 148 d before artificial insemination (AI), allowing time for the mineral status of heifers to be altered …

Yearling Bulls Have Reduced Sperm Concentration And Increased Seminal Plasma Interleukin-8 After A 28-Day Breeding Season, Alexandria P. Snider, Kacie L. Mccathy, Elane C. Wright-Johnson, Jeffrey D. Ondrak, William T. Oliver, Carl R. Dahlen, Robert A. Cushman, Matthew S. Crouse

Department of Animal Science: Faculty Publications

We hypothesized that yearling bulls selected for a 28-d breeding season would have reduced sperm concentrations and morphology, and have increased seminal plasma concentrations of pro-inflammatory cytokine interleukin-8 (IL-8). Yearling bulls were selected based on a breeding soundness examination (BSE) at approximately 415 d of age and contained at least 750 million sperm in the ejaculate, with 12 bulls randomly selected for breeding (BREEDERS) and 12 bulls not selected for breeding (NON-BREEDERS). After a 28-d breeding period, all bulls underwent a BSE. Plasma and seminal plasma were collected at each time point for analysis. Data were analysed utilizing either the …

A Survey Of The Microbial Communities Of Commercial Presliced, Packaged Deli-Style Ham Throughout Storage, Rebecca A. Furbeck, Chad G. Bower, Samodha C. Fernando, Gary Sullivan

Department of Animal Science: Faculty Publications

The goal of this study was to evaluate the variation in spoilage microbiota associated with sliced, prepackaged deli-style ham from varying processing environments available in the retail market in the United States. Three different brands of presliced ham, water added were purchased at local markets and evaluated every 2 wk beginning 4 wk prior to the sell-by date until 4 wk beyond the sell-by date. Analysis of 16S ribosomal RNA genes using operational taxonomic units showed that Brand A had a different bacterial community structure compared with Brands B and C, according to unweighted (P = 0.006) and weighted …

Primary Myoblasts From Intrauterine Growth-Restricted Fetal Sheep Exhibit Intrinsic Dysfunction Of Proliferation And Differentiation That Coincides With Enrichment Of Inflammatory Cytokine Signaling Pathways, Robert J. Posont, Micah S. Most, Caitlin Cadaret, Eileen Marks-Nelson, Kiristen A. Beede, Sean W. Limesand, Ty B. Schmidt, Jessica L. Petersen, Dustin T. Yates

Department of Animal Science: Faculty Publications

Intrauterine growth restriction (IUGR) is linked to lifelong reductions in muscle mass due to intrinsic functional deficits in myoblasts, but the mechanisms underlying these deficits are not known. Our objective was to determine if the deficits were associated with changes in inflammatory and adrenergic regulation of IUGR myoblasts, as was previously observed in IUGR muscle. Primary myoblasts were isolated from IUGR fetal sheep produced by hyperthermia-induced placental insufficiency (PI-IUGR; n = 9) and their controls (n = 9) and from IUGR fetal sheep produced by maternofetal inflammation (MI-IUGR; n = 6) and their …

Identification Of Genomic, Proteomic, And Metabolomic Signatures Associated With Pulmonary Hypertension Syndrome In Broilers, Duaa Almansaf

Graduate Theses and Dissertations

The present dissertation contains a collection of studies that examine the genomic, proteomic, and metabolomic association to pulmonary hypertension or ascites phenotype in fast-growing broilers. Pulmonary hypertension is a multifactorial metabolic disease influenced by physiological, environmental, and nutritional factors. It is characterized by a number of structural changes including, thrombosis and adverse pulmonary vascular remodeling. Thus, the atrial pressure is increased, and the right ventricle becomes hypertrophied, resulting in heart failure and the death of the bird. Pulmonary hypertension or ascites is a global problem that has negatively impacted the economy. The increased mortality rate of broilers (25%) is estimated …

Validation Of Whole Genome Resequencing For Mapping The Genetics Of Ascites In Broilers And Viral Susceptibility In Layers, Katherine Pepper Lee

Graduate Theses and Dissertations

This dissertation focused on the efficacy and validity of whole genome resequencing (WGR) for fine mapping genetic determinants of particular traits in a given organism. Previously, our research group used WGR to identify haplotype blocks of single nucleotide polymorphisms associated with ascites resistance with some as strong candidates for use in marker-assisted selection (MAS). Chapter 2 discusses the completion of a MAS project through evaluation of ascites incidence as well as production traits of economic value to poultry producers. Thus, the MAS project also covered viability of this methodology in the industry. The MAS significantly reduced ascites incidence in broilers …

Estimates Of Daily Oxygen Consumption, Carbon Dioxide And Methane Emissions, And Heat Production For Beef And Dairy Cattle Using Spot Gas Sampling, C. Lee, K. A. Beauchemin, J. Dijkstra, D. L. Morris, K. Nichols, Paul J. Kononoff, D. Vyas

Department of Animal Science: Faculty Publications

A simulation study was conducted to examine accuracy of estimating daily O₂ consumption, CO₂ and CH₄ emissions, and heat production (HP) using a spot sampling technique and to determine optimal spot sampling frequency (FQ). Data were obtained from 3 experiments where daily O2 consumption, emissions of CO2 and CH4, and HP were measured using indirect calorimetry (respiration chamber or headbox system). Experiment 1 used 8 beef heifers (ad libitum feeding; gaseous exchanges measured every 30 min over 3 d in respiration chambers); Experiment 2 used 56 lactating Holstein-Friesian cows (restricted feeding; gaseous exchanges measured every 12 min …

Genetic Protocols For Dna Extraction From White-Tailed Deer Cast Antlers To Confirm Individuality, Zach Carter, Brian C. Peterson, Casey W. Schoenebeck, Kimberly A. Carlson

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

White-tailed deer (Odocoileus virginianus) are the most sought-after deer species in America. The antlers of mammals, such as deer, are one of the fastest regenerative tissues in the world and are grown and naturally cast every year. Research on cast antlers have been used for a variety of purposes including population comparisons and impacts of deer health due to climatic stressors. When investigating cast antlers, it is important to confirm individuality of match sets in addition to antlers of the same individual between years. Therefore, individuality must be confirmed genetically, and protocols must be developed and established to …

Vitamin And Mineral Supplementation And Rate Of Gain In Beef Heifers I: Effects On Dam Hormonal And Metabolic Status, Fetal Tissue And Organ Mass, And Concentration Of Glucose And Fructose In Fetal Fluids At D 83 Of Gestation, Ana Clara B. Menezes, Kacie L. Mccathy, Cierrah J. Kassetas, Friederike Baumgaertner, James D. Kirsch, Sheri T. Dorsam, Tammi L. Neville, Alison K. Ward, Pawel P. Borowicz, Lawrence P. Reynolds, Kevin K. Sedivec, J. Chris Forcherio, Ronald Scott, Joel S. Caton, Carl R. Dahlen

Department of Animal Science: Faculty Publications

Thirty-five crossbred Angus heifers (initial BW = 359.5 ± 7.1 kg) were randomly assigned to a 2 × 2 factorial design to evaluate effects of vitamin and mineral supplementation [VMSUP; supplemented (VTM) vs. unsupplemented (NoVTM)] and different rates of gain [GAIN; low gain (LG), 0.28 kg/d, vs. moderate gain (MG), 0.79 kg/d] during the first 83 d of gestation on dam hormone and metabolic status, fetal tissue and organ mass, and concentration of glucose and fructose in fetal fluids. The VMSUP was initiated 71 to 148 d before artificial insemination (AI), allowing time for mineral status of heifers to be …

Breeding Sustainable Beef Cows: Reducing Weight And Increasing Productivity, Warren M. Snelling, R. Mark Thallman, Matthew L. Spangler, Larry A. Kuehn

Department of Animal Science: Faculty Publications

Programs for sustainable beef production are established, but the specific role of beef cows in these systems is not well defined. This work characterized cows for two traits related to sustainability, cow weight (CW) and cumulative weight weaned (WtW). Cow weight indicates nutrient requirements and enteric methane emissions. Cumulative weight weaned reflects reproductive performance and avoidance of premature culling for characteristics related to animal health, welfare, and worker safety. Both traits were evaluated with random regression models with records from a crossbred population representing 18 breeds that conduct US national cattle evaluations. The genomic REML analyses included additive and dominance …

Insights Into The Speciation Process From Genomic And Phenotypic Analysis Of An Avian Hybrid Zone In Amazonia, Glaucia Christina Del-Rio

LSU Doctoral Dissertations

Understanding the outcome of secondary contact is essential to shed light on the mechanisms governing species formation and maintenance. In Amazonia, closely related bird taxa with limited dispersal abilities are often separated by rivers, which presumably act as dispersal barriers. However, at the headwaters, rivers cease to be dispersal barriers, and this generates opportunities for secondary contact. In my dissertation, I studied genomic mechanisms associated with phenotypic differences, mitochondrial DNA structure, and putative reproductive barriers between two hybridizing Amazonian bird species in the genus Rhegmatorhina, a group of antbirds that find their arthropod prey exclusively by following army-ant swarms. …

Beta-Adrenergic Agonists Alter Oxidative Phosphorylation In Primary Myoblasts (Short Communication), Renae Sieck, Leah K. Treffer, Anna M. Fuller, Martonio Ponte Viana, Oleh Khalimonchuk, Ty B. Schmidt, Dustin T. Yates, Jessica Lynn Petersen

Department of Animal Science: Faculty Publications

Beta-adrenergic agonists (β-AAs) are widely used supplements in beef and pork production to improve feed efficiency and increase lean muscle mass, yet little is known about the molecular mechanism by which β-AAs achieve this outcome. Our objective was to identify the influence of ractopamine HCl and zilpaterol HCl on mitochondrial respiratory activity in muscle satellite cells isolated from crossbred beef steers (N = 5), crossbred barrows (N = 2), Yorkshire-cross gilts (N = 3), and commercial weather lambs (N = 5). Real-time measurements of oxygen con­sumption rates (OCRs) were recorded using extracellular …