Animal Sciences Commons^™

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 …

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 …

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

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

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

The Utilization Of Brown Midrib Corn Silage Hybrids And Kernel Processing To Improve Corn Silage Value And The Use Of High Protein Distillers Grains To Evaluate Starch Digestion, Lauren A. Ovinge

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

Three studies evaluated the effects of corn silage hybrid, inclusion level and kernel processing in growing and finishing diets. Two more studies were conducted on high protein dried distillers grains and its effect in finishing diets. Experiment 1 and 2 evaluated three corn silage hybrids; standard (CON; hybrid-TMF2H708), brown midrib (bm3; hybrid-F15579S2) and Unified™ brown midrib with SilaSoft™ kernel technology with a floury endosperm (bm3-soft; hybrid-F15578XT) harvested with or without kernel processing on growth and metabolism. Experiment 3 evaluated a brown midrib hybrid (bm3; hybrid-F27F627; Mycogen® Seeds) or a control (CON; hybrid-TMF2H708) in the diet …

Assessing Plant-Wax Markers As A Tool To Estimate Intake And Diet Composition In Beef Cattle, Emily J. Hilburger

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

Estimating feed efficiency of ruminants in grazing environments is difficult due to challenges in measuring intake and diet composition of animals that are freely grazing. Plant-wax markers, especially n-alkanes (ALK), have been shown to be a potential tool to calculate intake and diet composition.

Two indoor experiments were conducted in successive years to assess ALK reliability to facilely estimate DMI (EDMI) and diet composition. Heifers were fed a ration of 69.8% corn silage and 30% ground alfalfa with a daily supplement containing a ALK marker (C₃₂). Using a pooled fecal sample increased the …

Use Of Byproducts In Forage-Based, Post-Weaning Beef Systems And Effects Of Serial Slaughter On Performance And Profitability, Robert G. Bondurant Jr.

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

Crude glycerin was included in high-forage beef growing diets at 0, 4, 8, and 12% diet DM to determine the effect on fiber digestion by evaluating changes in microbial species abundance, NDF digestibility, and VFA concentrations. Total tract NDF digestibility decreased with increasing inclusion of GLY in high-forage diets. However, there was no decrease in in situ NDF digestibility and Fibrobacter succinogenes microbial populations were unaffected, indicating that fiber digestion was not directly affected by inclusion of GLY. Acetate decreased while propionate and butyrate VFA proportions increased as GLY increased.

Spayed heifers were utilized in a 2-yr study to evaluate …

Effects Of Field Pea Usage In Growing And Finishing Diets For Beef Cattle, Hannah L. Greenwell

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

The value of field peas (FP) as a feedstuff has not been thoroughly assessed and compared to other feeds, such as corn, to better establish an economic value. Field peas are characterized by a high CP content (23-26%), a large portion (80%) being rumen degradable protein (RDP), and containing almost a third less starch (31-40%) than corn. Three research trials were performed to better understand the value of FP as a grazing supplement, finishing diet component, and any effects on digestion. Experiment 1 assessed the value of FP as a grazing supplement compared to corn. Grazing was followed by a …

Evaluation Of The Metabolic Response, Blood Chemistry Profile, And Cardiac Morphology Of Beef Heifers Supplemented With Zilpaterol Hydrochloride Followed By An Endocrine Induced Stress Challenge, Joe O. Buntyn

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

The objective of this study was to determine the metabolic, stress, hematology, organ weights, histology and cardiac anatomical features of beef heifers supplemented with zilpaterol hydrochloride (ZH) when exposed to a corticotropin-releasing hormone (CRH) and arginine vasopressin (VP) challenge. Crossbred heifers (n = 20; 556 ± 7 kg BW) were randomized into two treatment groups: 1) Control (CON): no ZH, and 2) Zilpaterol (ZIL): supplemented with ZH at 8.33 mg / kg (DM basis). The ZIL group was supplemented ZH for 20 d, with a 3-d withdrawal period. On d 24, heifers received an intravenous bolus of CRH (0.3 µg …

Evaluation Of Hematological And Serum Biochemical Profiles Associated With The Supplementation Of Zilpaterol Hydrochloride To Feedlot Heifers, Sara Elizabeth Sieren

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

Supplementation of zilpaterol hydrochloride (ZH; Zilmax^®) to cattle has been suggested to have a negative impact on well-being of cattle. The objective of this study was to evaluate the hematological and serum biochemical profiles in feedlot heifers supplemented with ZH in a minimal stress environment. Heifers were randomly assigned to one of two treatment groups: Control (CON no ZH), or ZH (supplemented with ZH at 8.33mg/kg of feed on a DM basis). The study was conducted over a period of 25 d (-2 to 23), with three serum collection periods [-2 to 4 d (ZH supplementation began on …

The Effect Of Diet On The Bovine Rumen Microbial Community Structure And Composition And Its Effects On Methane Production In Growing And Finishing Cattle, Allison L. Knoell

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

Methane is a potent greenhouse gas (GHG) that contributes to global warming. A natural by-product of ruminant fermentation is the production and eructation of methane. Methane is produced by a small unique group of microorganism’s called methanogens that belong to the domain Archaea. Enteric methane represents 2-12% energy loss in ruminants. It is well established that diet affects the microbial community structure and composition. Fermentative products of the mixed microbial population (bacteria, fungi, and protozoa) become the substrates for methanogens. These substrates influence which microorganisms will thrive. However, the effect of diet on the microbial community while simultaneously calculating …

Dietary Strategies For Mitigation Of Methane Production By Growing And Finishing Cattle, Anna C. Pesta

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

Interest in reducing methane (CH₄) emissions by cattle has increased recently. Loss of feed energy as CH₄ represents both an environmental concern and an energetic loss to the animal. Manipulation of dietary composition has proven to be an effective mitigation strategy. Experiments were conducted to evaluate the effect of several dietary characteristics on CH₄ production in growing and finishing cattle, and to develop a novel, non-invasive method for quantifying emissions from animals in a production setting. Short-term gaseous emissions of CH₄ and carbon dioxide (CO₂) were measured and the CH₄:CO_{2 …}

Changes In Corn Residue Quality Throughout The Grazing Period And Effect Of Supplementation Of Calves Grazing Corn Residue, Amanda J. Burken

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

Corn residue is an abundant feed source in Nebraska that can be utilized as an alternative winter feed. Calves were backgrounded on corn residue in order to determine gain and estimate forage intake when supplemented with distillers grains (DGS). Calves grazing the non-irrigated field gained more (1.03 kg/calf daily) when compared to those grazing the irrigated field (0.90 kg/calf daily; P < 0.01). In year 1, a quadratic effect for intake of DGS was present (P < 0.01) while year 2 observed a linear effect for increasing level of DGS (P < 0.01). The nutritional quality of corn residue was evaluated over time in order to determine changes in blade/sheath, cob, husk/shank and stem. Minimal changes in DM of the forage components occurred was grain reached 15.5% moisture. Digestibility of the blade/sheath declined linearly over time (P < 0.01) while the husk remained constant (P = 0.40). Cob digestibility decreased quadratically (P < 0.01) throughout the sampling period with few changes once grain reached 15.5% moisture. Differences observed in the digestibility of the blade/sheath were attributed to the effects of weathering. A third set of trials was conducted to evaluate the effects of by-product supplementation of calves grazing irrigated corn residue and supplemented with DGS or continuous access to lick tubs. The DGS treatment gained more (0.62 kg/calf daily) than the lick tub treatment (0.38 kg/calf daily; P < 0.01). Calves offered DGS consumed more supplement as a percentage of BW (0.52%) when compared with calves offered lick tubs (0.36%; P < 0.01) on a DM basis. Calves supplemented with DGS had a higher supplement efficiency (46.3% to 42.9%, DM basis) although no differences were present between treatments (P = 0.49). When analyzed on an OM basis, however, calves offered lick tubs had a numerically higher supplement efficiency (50.4%) in comparison to calves …

Feedlot Manure Management Considerations Including Anaerobic Digestion Potential And Mineral Retention, Andrea K. Watson

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

Three anaerobic digestion trials were conducted to evaluate methane production from feedlot manure. As organic matter content of manure decreased, degradation of manure and methane production also linearly decreased (P ≤ 0.02). Quality, or organic matter content of manure, had a greater impact on anaerobic digestion than diet (with and without distillers grains) fed to cattle. Minerals are concentrated in effluent removed from anaerobic digesters.

Knowing mineral retention within cattle allows for more accurate calculation of mineral excretion in manure. Three serial slaughter trials measured mineral retention in growing and finishing cattle. During a growing phase, beef cattle gaining …

Feeding Alkaline Treated And Processed Crop Residue To Feedlot Cattle, Sarah J. Peterson

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

Chemical treatment and decreased particle size are methods used to improve digestibility and utilization of the available nutrients in low quality forages. Previous research has indicated that chemically treated corn residue can take the place of corn when included in finishing rations containing distillers grains. Also, decreasing particle size utilizing methods such as pelleting has been shown to improve DMI and ADG. However, limited research has been completed on use of chemical treatment and pelleting in growing and receiving rations. Also, an ideal distillers inclusion has not yet been identified when including alkaline treated stalks in finishing rations. Therefore, a …

Determining Forage Intake Of Nursing Calves Grazing Native Sandhills Rangeland, Jennifer A. Walker

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

Effective management of grazing lands is important for longevity and productivity. Accurate calculations of stocking rates per animal unit will aid in long term sustainability. Calculating stocking rates for cattle can prove challenging for cows and nursing calves. Limited research has been conducted to determine forage intake of the nursing calf pre-weaning. The objective of Trial 1 was to determine nursing calf forage intake over time until weaning. Trial 1 used 8 crossbred cow-calf pairs in experiment 1 and 12 pairs in experiment 2. Pairs were separated into two groups rotating between grazing upland range or housed in individual pens …

Model Development For The Prediction Of Intake And Carcass Measures To Be Used As Economic Marketing Determinants For Calf-Fed Steers, Mallorie F. Wilken

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

Accurate prediction of intake and carcass characteristics can assist in projecting input costs and potential premiums when cattle are sold at optimum finishing so net profit/loss can be anticipated. Currently published DMI prediction equations and dietary NE values are based off of data collected over 50 years ago and have been shown to inaccurately predict intake compared to a prediction equation based of off performance data. Calculating dietary NE values from performance data increased precision and accuracy of prediction. Additionally, prediction accuracy was increased for diets containing ethanol byproducts. Since ethanol byproducts have been shown to have 110 to 140% …

Effect Of Residue Removal On Subsequent Year Quality And Quantity Of Corn Residue And Cattle Performance While Grazing Corn Residue At Different Stocking Rates, Adam L. Mcgee

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

Two studies evaluated the impact of residue removal; study 1, grazed in the fall or spring, study 2, removed by grazing at two stocking rates, light (LG), heavy (HG), or baled(B). There were no differences in pre-grazing treatments for digestibility, CP, NDF, plant fraction as a percent of residue and kg/25.5 kg of grain. Digestibility was highest in husk and lowest in stem. CP was greatest in leaf blade and lowest in husk. NDF was highest in the leaf sheath and lowest in the cob while stem is the greatest percentage of the plant and husk the smallest. The fractions …

Effects Of Feeding Insect-Protected Corn And Corn Residue To Cattle, And Evaluation Of Distillers Grains Storage When Mixed With Crop Residue On Cattle Performance, Barry Weber

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

Research has been conducted on genetically modified corn fed to livestock since the introduction of insect resistant hybrids. While the overwhelming conclusion of these trials demonstrate nutritional equivalency to corn from non-transgenic hybrids, the introduction of new transgenes and combinations of resistance traits necessitates continued evaluation of genetically modified corn hybrids. Expansion of the ethanol industry has resulted in the increased availability of co-products for use as a livestock feed, as well as an increase in crop residues that offer unique opportunities for use by cattle producers. A finishing trial was conducted with corn and corn silage from MON 89034, …

Supplementing Distillers Grains In Extensive Beef Cattle Systems, Kelsey Rolfe

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

A 3-yr study evaluated effects of supplementing modified wet distillers grains with solubles during summer grazing and subsequent feedlot sorting on long yearling steers. During summer grazing, supplemented steers had greater ADG and were more profitable than non-supplemented steers. At feedlot entry, supplemented steers were 48 kg heavier than non-supplemented steers. Feed efficiency and DMI were not different between supplementation treatments during finishing. Supplemented steers were fed 24 fewer days to reach a similar 12^th rib fat thickness, had greater LM area, and lower marbling compared to non-supplemented steers. Overall profitability favored supplementing steers because less expensive summer gains …

The Use Of High Distillers Grains And Nutrient Management In Beef Feedlots, Amy R. Rich

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

Two experiments were conducted to determine the effect of feeding wet distillers grains (WDGS) at 70% and wheat straw at 25% (DM basis) on finishing steer performance and N mass balance in open feedlot pens. Four treatments were tested as a 2x2 factorial with factors being diet and pen cleaning frequency (monthly or at the end of the feeding period). In both experiments the CON treatment (corn based diet) had greater DMI, ADG, HCW, marbling and fat depth. There was greater N intake and N excretion for both the WINTER and SUMMER experiments on the WDGS. Not all the additional …

Ethanol Byproduct Feeds: Determining Accurate Fiber Content, Nutrient Composition And Variability, Storing With Low-Quality Forages, And Fiber Utilization In Finishing Diets, Crystal D. Buckner

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

The growing ethanol industry has produced vast quantities of distillers grains plus solubles (DGS) in the wet (WDGS) and dry forms and Sweet Bran wet corn gluten feed (SB). Previous research has demonstrated that these byproduct feeds result in improved feeding values compared to grass in growing diets and corn in finishing diets, with positive economic returns. Four experiments were conducted to evaluate dry matter determination methods and variability of nutrient composition for WDGS, determining the accurate method for measuring NDF in corn and DGS, compare feeding WDGS mixed with straw as either fresh or ensiled, and evaluate fiber digestibility …