Animal Sciences Commons^™

Utilization Of The NuTrack System To Objectively Evaluate Changes In Active And Passive Behaviors Of Group-Housed Nursery Pigs Exposed To An Endotoxin Challenge, Aaron Holliday

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

This study aimed to evaluate the changes in activity of group-housed, newly weaned pigs challenged with lipopolysaccharide (LPS). At weaning, pigs (n = 192, 5.73 ± 1.8 kg) were stratified by sex, litter, and body weight (BW) and randomly assigned to one of three treatments (16 pigs/pen, 4 pens/treatment): 1) Saline-injected (SAL), 2) 50% challenged [50%-LPS) – only half of the pigs in a pen (8 pigs) were challenged with LPS and 3) 100% challenged (100%-LPS) – all pigs in a pen were challenged with LPS. Pigs in the SAL and 32 in the 50%-LPS treatment received a 3.0 …

Adding Parasite Resistance To A Hair Sheep Breeding Objective, Bob Forbes

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

The U.S. Hair Sheep Index was designed to increase total weight of lamb weaned per ewe lambing (TW) using estimated breeding values (EBV) for direct (DWWT) and maternal (MWWT) weaning weight, and number of lambs born (NLB) and weaned (NLW), as selection criteria. Producers are interested in adding post-weaning fecal egg count EBV (PFEC), an indicator of parasite resistance, to the index to achieve genetic change in both TW and PFEC.

First, the effects of adding PFEC alongside TW to the breeding objective of indexes that used either phenotypes or EBV as selection criteria were studied. Since MWWT is …

Feeding Dried Distillers Grains With Solubles To Lactating Dairy Cattle: Whole Animal Energy Utilization And Manure Biogas Production, Grant Michael Fincham

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

When DDGS are fed to lactating dairy cattle, the observed response in energy supply, milk production, and methane production varies among studies. One potential reason for these observed discrepancies is the nature of the diet formulation itself. Furthermore, little research has been conducted to examine how dietary changes can affect dairy cattle manure composition and methane production in an anaerobic manure digester. In order to gain a better understanding of these topics, we conducted two experiments. The first experiment was conducted to test how the manipulation of lactating dairy cattle diets affects energy utilization, milk production, methane production, and manure …

Artificial Insemination And Fetal Programming In Beef Production Systems, Dempster Christenson

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

Pregnancy to artificial insemination and late gestation fetal programming of the next calf crop are central to genetic development, reproductive longevity, calf crop productivity, and efficiency of cow/calf ranching. The purposes of this research are to find methods to improve pregnancy rate to artificial insemination, the growth and reproductive health of pregnant heifers, and the productivity of their offspring. In the first of four studies we found that extending the period of progesterone administration in an estrus synchronization protocol did not significantly hasten estrus response or increase pregnancy rate to artificial insemination, but timing of estrus within the melengestrol acetate …

Feed Value And Utilization Of Corn Residue: Implications For Cow Performance And Grazing Strategies, Kaylee E. Wheeler

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

Two experiments were conducted to determine the correlation of corn residue feed value and utilization on cow performance and potential grazing strategies. A qualitative observation of corn residue grazing by 13 cattle herds across Nebraska was conducted over two years. Based on producer reported grain yields and stocking rates, it was found that these producers were generally not as aggressive as the recommended 1.2 animal unit months (AUM) for each 6,280 kg/ha (100 U.S. bushels/acre) of harvested grain. They stocked 17 to 101% of the recommendation and on average used 63% of the carrying capacity. Across herds, average body condition …

Investigation Of Breeding Objectives And Indexes-In-Retrospect, Hunter F. Valasek

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

This thesis presents two projects that investigate the impacts of breeding objectives and indexes-in-retrospect within the beef cattle industry. The first project synthesized how changes due to planning horizon, breeding system, and sale endpoint in the economic breeding goal of cattle influence the relative emphasis of traits as well as the re-ranking of selection candidates. A total of three breeding systems that represent straightbred and crossbred cattle were used along with six planning horizons (2, 5, 10, 20, 30, and 50 yrs.) for both a weaning and slaughter point of sale. The combination of these different breeding objective attributes resulted …

Supplemental Table 1. Influence Of The Count Of Positive Days On Dmi, Milk Yield, Milk Fat, Milk Protein, And Pregnancy Rate, Addison Carroll, Paul J. Kononoff

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

Response

Intercept

Devstarch

Devfat

DevNDF

DevPro

BIC

Dry-Aged Beef Flavor Development, And The Effect Of High Levels Of Vitamin-E On Beef Color Stability, Nicolas Herrera

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

Palatability and consumer purchasing are essential factors of fresh meat. To meet consumer expectations during purchasing and consumption, fresh beef must maintain desirable cherry-red color at retail and achieve desirable cooked flavor. Dry-aged beef popularity has grown, and identifying methods to ensure quality dry-aged meat is necessary to maintain demand. To understand dry-aged palatability, this dissertation addressed effects of moisture loss and aging time, fundamental factors of dry-aged beef, using bone-in and boneless strip loins. Study two investigated flavor development using cookery methods and internal temperatures in boneless and bone-in dry-aged beef. In study one, increased dry-aging time (creation effect) …

Identification And Assessment Of Lameness In Sows Through The Utilization Of Nutrack And Gaitfour Systems, Lexi M. Ostrand

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

Lameness is a financial concern for producers and a welfare concern for the animals. Utilizing both the GAITFour and NUtrack systems, gilts’ natural tendencies and gait were analyzed to better understand the onset of lameness and what indicators can be identified in a commercial setting. Beginning at 20 weeks of age, video on replacement gilts was collected for 9 consecutive days and processed using the NUtrack System to identify individual gilts’ distance travelled (m), avg speed (m/s), angle rotated (degrees), and time standing (s), sitting (s), eating (s), and laying (s). NUtrack is a deep learning-based multi-object …

Consequences Of Cow-Calf Production With Limited Perennial Forage Grazing, Hannah Speer

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

Conversion of perennial grasslands to cropland and rising land prices prompts a need to evaluate alternative beef cow-calf production systems. A 3-yr study was conducted comparing beef cow-calf performance between two August-calving cow systems: perennial forage and corn residue grazing; or summer drylot, fall grazing of late-summer-planted cover crop, and corn residue grazing. Cow body condition score differed between systems, but condition of cows in both systems never fell below adequate. There were no differences in pregnancy rates between systems. Calf weaning weights differed between systems each year; differences are attributed to feedstuff quantity, quality, and type available to calves …

Impact Of Distillers Removal And Impact Of Lowering Inclusions Of Distillers Grains Plus Solubles And Different Roughage Quality On Finishing Cattle Performance, Sofia Suarez Lorences

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

A feedlot trial (Exp. 1) was conducted to evaluate the impact of removing modified distillers grains plus solubles (MDGS) on performance and carcass characteristics. Cattle with MDGS removed on either d 79 or d 43 had reduced final BW, DMI, and ADG. Cattle with MDGS removed on d 43 were 5% less efficient than cattle fed 20% MDGS throughout the entire 124-d feeding period. Cattle fed 20% MDGS throughout the whole feeding had the greatest HCW and LM area. There were no differences in backfat and marbling scores among treatments, and no differences in percent of abscessed livers. In conclusion, …

Mid-Gestation Maternofetal Inflammation Impacts Growth, Skeletal Muscle Glucose Metabolism, And Inflammatory Tone In The Ovine Fetus During Late Gestation, Zena Hicks

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

Our 1^st and 2^nd studies assessed the impact of mid-gestation maternofetal inflammation on growth, skeletal muscle glucose metabolism, and inflammatory tone in the late gestation ovine fetus. The objective was to determine if inducing maternofetal inflammation during peak placental growth would lead to more profound IUGR characteristics in the fetus. MI-IUGR fetuses exhibited reduced body and skeletal muscle weights and hallmark asymmetric growth at late gestations. Fetuses had higher baseline glucose:insulin ratios and reduced glucose-stimulated insulin secretion. Moreover, hindlimb glucose oxidation was impaired independent of glucose uptake. Skeletal muscle specific glucose uptake and oxidation was reduced in MI-IUGR …

Effect Of Supplementation Prior To Artificial Insemination And During Gestation In Beef Females, Landon Tadich

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

Objectives of Experiment 1 was to evaluate the impact of increased energy prior to AI on BW, ADG, and reproductive efficiency in heifers developed on range or in a dry lot. During the winter development period (131 ± 3.5 d/yr) heifers (n= 100/yr) were assigned to either upland range (RANGE) or fed a dry lot diet in two pens that either remained constant (DLLO) or increased in energy prior to AI (DLHI). Heifers developed on RANGE grazed upland winter range until 38 d prior to AI where they then received the DLLO diet. Pre-breeding BW was greater (P £ …

Winter Hardy Small Cereals For Grazing Or Silage In Eastern Nebraska, Abigail Sartin

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

Two, 3-year studies were conducted to evaluate the value of cereal rye, winter wheat, and winter triticale as forage sources for either for silage or early spring grazing. For silage, the objective was to evaluate species and maturity effects on dry matter yield, nutritive value, and fermentation of small cereal silage. There are no major differences between wheat, rye, or triticale in terms of the relative timing of each species reached each maturity stage. There are no differences among species in dry matter (DM) yield, except for wheat which tends to decline at soft dough due to senescence of the …

Methods To Reduce Nitrogen And Carbon Losses From Finishing Beef Cattle, Hanna Cronk

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

A finishing experiment evaluated the effect of incremental supplemental rumen-protected lysine on beef cattle performance. All cattle were fed the same diet of high moisture corn, dried rolled corn, modified distillers grains plus solubles, corn silage, and supplement with inclusion levels of lysine ranging from 0 to 7 grams/day, in 1 g increments. Dry matter intake (P 0.04) and ADG (P ≤ 0.04) decreased linearly as supplemental lysine increased in the diet with no effect on final carcass adjusted feed efficiency (P ≥ 0.34). In the initial 64 days of the experiment, increasing lysine in the diet …

The Evaluation Of Encapsulated Megasphaera Elsdenii In An Accelerated Beef Step-Up Program And An Acidosis Challenge Model And The Evaluation Of Ramp Versus A Traditional Forage Grain Adaptation Strategy On Methane And Respired Carbon Dioxide, Cindy D. Mansfield

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

A metabolism experiment (Exp 1) was conducted to evaluate daily feeding of encapsulated Megasphaera elsdenii (M. elsdenii) NCIMB 41125 along with a one-time drench of 1×10¹¹ CFU of M. elsdenii on dry matter intake (DMI), in-vitro lactate utilization, volatile fatty acid (VFA), and lactate concentration. Treatments consisted of steers which were fed no M. elsdenii (CONTROL), steers drenched with the commercial dose 1×10¹¹ CFU of M. elsdenii (LactiproNXT) on d 1 of the experiment and received no other M. elsdenii (DRENCH), and steers drenched with a commercial dose of LactiproNXT on d 1 of the experiment …

The Invisible Meat Microcosmos - Investigations Of Processed Meats' Specific Spoilage Organisms, Rebecca Furbeck

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

As humankind grows in population, so will our need to compete against bacterial populations which spoil foodstuffs before we are able to consume them. This dissertation aims to identify the bacterial communities responsible for meat spoilage, and the mechanisms that govern the behaviors of these organisms. The literature review summarizes the state of knowledge regarding factors that influence meat microbiome composition, and how analytical methods can influence research outcomes. Study 1 aimed to identify the impact of additional ingredients and processing steps on the microbial ecology of processed turkey products. The main specific spoilage organisms (SSOs) belonged to the orders …

Molecular Mechanisms Underlying Aberrant Circulating Steroid Hormones In Gnrhr-Ii Knockdown Boars And Their Control Littermates, Dorothy Elsken

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

Swine are the only livestock species that produce a functional protein for both GnRH-II and its receptor (GnRHR-II). Our laboratory reported that the interaction between GnRH-II and GnRHR-II facilitates testosterone production, independent of LH stimulation. To further examine GnRHR-II function, we developed a swine line with 70% reduced GnRHR-II mRNA levels (GnRHR-II KD) compared to control littermates. Mass spectrometry analysis of serum revealed that circulating levels of gonadal steroids were reduced in mature transgenic vs. control boars. Paradoxically, evaluation of testicular tissue indicated no difference between lines for gonadal steroid hormone levels. To address a potential cause for this discrepancy, …

Variance Component Estimates For Growth Traits In Beef Cattle Using Selected Variants From Imputed Low-Pass Sequence Data, Chad A. Russell

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

A beef cattle population (n=2,343) was used to assess the impact of variants identified from imputed low-pass sequence (LPS) on the estimation of variance components and genetic parameters of birth weight (BWT) and post weaning gain (PWG). Variants were selected based on functional impact and were partitioned into four groups (Low, Modifier, Moderate, High) based on predicted functional consequences and re-partitioned based on consequence of mutation, such as missense and untranslated region variants, into six groups (G1-G6). Each subset was used to construct a genomic relationship matrix (GRM) for univariate animal models. Multiple analyses were conducted to compare the proportion …

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 …

Impacts Of Feeding Biochar To Beef Cattle On Greenhouse Gas Emissions And Performance And Characterizing Yearling Steers Grazing Smooth Bromegrass Pasture Using Gps, Holly Heil

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

As global warming continues to rise, the pressure and growing demand for sustainable animal production is increasing. Livestock naturally produce greenhouse gas emissions through enteric fermentation. Dietary manipulation strategies have been sought out to decrease emissions in ruminants using feed additives.

Two independent finishing feedlot experiments evaluated two types of biochar and its effects on animal performance, carcass characteristics and greenhouse gas emissions. Experiment 1 utilized pistachio shell biochar and experiment 2 utilized biochar sourced from ponderosa pine wood waste, both types included at 1% of the diet DM. The addition of biochar to the diet did not impact animal …

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 …

Identifying Early-Life Behavior To Predict Mothering Ability In Swine Utilizing Nutrack System, Savannah 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 include …

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 RUP …

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 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 lactation …

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 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 Extension Service, …

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