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 …

Forages And Technology Management In Growing And Finishing Beef Cattle Systems, Kelton Adair

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

A systems study evaluated the effects of an implant [25.7 mg estradiol (Compudose; Elanco Animal Health)] at two rates of gain (LOW: 0.45 kg/d and HIGH: 0.9 kg/d) applied during the winter backgrounding phase in drylot and winter grazing systems and its effects on subsequent phases of production. HIGH supplementation with an implant during the winter backgrounding phase in the drylot system yielded the greatest ending body weight (EBW) during the summer backgrounding phase (P = 0.04). LOW supplementation, without an implant, improved summer backgrounding average daily gain (ADG; P = 0.05) while achieving similar carcass adjusted final body …

Predicting Body Weight Of Cattle And Nutrient Digestion Of Individual Sweet Bran Components To Improve Beef Cattle Production Efficiency, Dalton J. Anderson

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

Efficiency is of high importance to beef cattle producers to ensure that beef cattle are being raised without unnecessary resource use. Two separate experiments were conducted to evaluate potential strategies to improve efficiency in beef cattle production. A metabolism study was conducted to evaluate digestion parameters of individual Sweet Bran components. The objective was to determine the effects of diet components on nutrient digestion and rumen fermentation parameters. The individual components of Sweet Bran (Corn bran, solvent-extracted germ meal, and corn steep liquor) were included at 40% diet dry matter (DM) in a steam-flaked corn (SFC) based diet. A SFC-based …

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 …

The Evaluation Of Feed Additives On Reducing Enteric Methane Production From Cattle, Reba L. Colin

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

Environmental sustainability can be positively impacted by the inclusion of feed additives to reduce enteric methane production from cattle. Methane production can be affected by feed additives that either alter the rumen environment or act as methanogenesis inhibitors. A reduction in methane from cattle can contribute to meeting carbon neutrality.

A metabolism study was conducted to evaluate Alga 1.0, a product containing bromoform, fed to cattle to evaluate the effects on gas emissions. Treatments were (0, 69, or 103 g/d Alga 1.0) fed in a corn-based diet. Headbox-style indirect calorimeters were used to measure gas emissions. Feeding Alga 1.0 linearly …

The Impact Of Silage Inclusion In Diets With Different Corn Processing And The Effect Of Natural And Conventional Feeding Programs On Finishing Cattle Performance, Jessica L. Miller

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

A finishing experiment was conducted to determine the effects of natural and conventional feeding programs on finishing performance of steers and heifers. Factors were conventional and natural feeding programs in steers and heifers. Cattle assigned to the conventional program were fed diets that contained Rumensin (Elanco Animal Health), Tylan (Elanco Animal Health), MGA (Zoetis), and received growth promoting implants whereas cattle in the natural program received neither. Compared to natural fed cattle, G:F was improved by 15.5% when heifers were fed in a conventional program (P < 0.01) and 23.8% when steers were fed in a conventional program (P < 0.01). The incorporation of implants and feed additives within the finishing period increased …

Factors Affecting Forage Quality And The Subsequent Response In Production And Energy Metabolism In Lactating Jersey Cows, Kassidy Kate Buse

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

Forage quality is the potential of a forage to produce a production response in animals. Because of how essential they are in dairy cattle rations, forages can have major influence on the behavior and production of dairy cattle. In experiment 1, the effect of forage fragility on the rumen environment and digestibility was evaluated. Increasing the inclusion of a less fragile forage led to greater rumen retention time, which resulted in lower rumen pH and greater NDF digestibility. Experiment 2 evaluated the effects of diets high in either corn silage or alfalfa haylage supplemented with either corn- or soybased protein …

Early-Life Supplementation Of Omega-3 Polyunsaturated Fatty Acids Improved Growth And Skeletal Muscle Glucose Metabolism In The Heat Stress-Induced Iugr Neonatal Lamb, Melanie Ryann White

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

Our 1^st study determined whether metabolic deficits of IUGR-born neonatal lambs can be improved by ameliorating elevated inflammatory tone. Supplementation with ω-3 polyunsaturated fatty acids (ω-3 PUFA) improved hindlimb insulin-stimulated glucose oxidation rates and basal lactate secretion. Ex vivo skeletal muscle-specific glucose oxidation rates were improved when heightened inflammatory tone was moderated. Pancreatic β cell function in response to hyperglycemia was improved by ω-3 PUFA supplementation. Tempered inflammatory tone also partially recovered skeletal muscle glycogen stores. Thus, we found that targeting heightened inflammatory tone inherent in IUGR-born neonatal lambs moderately improved glucose metabolism and pancreatic β cell …

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

Students' Attitudes Towards Animals Influences Youth Development Constructs Based On Interactions With Different Animal Species Prior To College, Allison K. Pachunka

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

Human-animal interactions (HAI) are commonplace in society and play a consequential role in a variety of situations such as companion animal ownership, agriculture, or youth programs such as 4-H or FFA. Interacting with animals has been shown to provide developmental benefits to children. Positive youth development (PYD), measured by the Five Cs Model, is a framework that focuses on fostering youth’s potential through positive activities which has been studied specifically in 4-H. However, this framework has not been applied to other organizations such as the National FFA Organization (FFA) or to other young adults with less formal interactions with animals. …

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 …

The Nebraska 4-H Equine Advancement Level Program’S Role In Positive Youth Development Using The Five Cs Model: An Exploratory Study, Eunhye Mccarthy

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

Positive youth development (PYD) focuses on developing the strengths of youth through positive activities and behaviors rather than reducing negative tendencies. A well-researched model of PYD is the five C’s model that is popularly used in youth development organizations such as 4-H. The Nebraska 4-H Equine Advancement Level program was intended to serve as a guidebook for instruction and assessment of youth as they learn more about horses and horsemanship skills. Each of the four levels has an emphasis in developing a 4-H member’s responsibility, self-discipline, self-reliance, patience, and pride of accomplishments. The program was started approximately 30 years ago …

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 …

Students' Perceptions Of Online Equine Courses And Their Impacts On Learning Outcomes, Blaire (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 …

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 …