Life Sciences Commons^™

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 …

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, …

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 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 …

Genes Involved In Feed Efficiency Identified In A Meta-Analysis Of Rumen Tissue From Two Populations Of Beef Steers, Amanda K. Lindholm-Perry, Allison M. Meyer, Rebecca J. Kern-Lunbery, Hannah C. Cunningham-Hollinger, Taran H. Funk, Brittney N. Keel

Roman L. Hruska U.S. Meat Animal Research Center: Reports

In cattle, the rumen is an important site for the absorption of feed by-products released by bacterial fermentation, and variation in ruminal function plays a role in cattle feed efficiency. Studies evaluating gene expression in the rumen tissue have been performed prior to this. However, validating the expression of genes identified in additional cattle populations has been challenging. The purpose of this study was to perform a meta-analysis of the ruminal transcriptome of two unrelated populations of animals to identify genes that are involved in feed efficiency across populations. RNAseq data from animals with high and low residual feed intake …

Using Pooled Data For Genomic Prediction In A Bivariate Framework With Missing Data, Johnna L. Baller, Stephen D. Kachman, Larry A. Kuehn, Matthew L. Spangler

Department of Animal Science: Faculty Publications

Pooling samples to derive group genotypes can enable the economically efficient use of commercial animals within genetic evaluations. To test a multivariate framework for genetic evaluations using pooled data, simulation was used to mimic a beef cattle population including two moderately heritable traits with varying genetic correlations, genotypes and pedigree data. There were 15 generations (n = 32,000; random selection and mating), and the last generation was subjected to genotyping through pooling. Missing records were induced in two ways: (a) sequential culling and (b) random missing records. Gaps in genotyping were also explored whereby genotyping occurred through generation 13 …

Interaction Of Replacing Corn Silage With Soyhulls As A Roughage Source With Or Without 3% Added Wheat Straw In The Diet: Impacts On Intake, Digestibility, And Ruminal Fermentation In Steers Fed High-Concentrate Diets, Bryan W. Neville, Wayde J. Pickinpaugh, Lea J. Mittleider, Rebecca L. Moore, Kendall C. Swanson, Joel S. Caton

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Six ruminally cannulated steers [475.0 ± 49.6 kg initial body weight (BW)] were used in a 6 × 3 incomplete Latin square design (six treatments and three periods), to evaluate the impacts replacing of corn silage with pelleted soyhulls as roughage in high-concentrate finishing diets containing 30% modified distillers grains with solubles. Treatments were based on increasing dietary inclusion of soyhulls and consisted of: (1) Control (0), roughage supplied by dietary inclusion of 20% corn silage [dry matter (DM) basis]; (2) 50% replacement of corn silage with soyhulls (50); (3) 100% replacement of corn silage with soyhulls (100), and the …

Impacts Of Added Roughage On Growth Performance, Digestibility, Ruminal Fermentation, And Ruminal Ph Of Feedlot Steers Fed Wheat-Based Feedlot Diets Containing 30% Modified Distillers Grains With Solubles, Wayde J. Pickinpaugh, Bryan W. Neville, Rebecca L. Moore, Joel S. Caton

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Two experiments were conducted to evaluate the inclusion rate roughage in wheat-based diets containing modified distillers grains with solubles (MDGS) on feedlot performance (Feedlot Experiment), as well as digestibility, ruminal pH, and ruminal fermentation characteristics (Digestibility Experiment). The feedlot experiment utilized 72 Angus steers (392 ± 46.3 kg initial body weight) which were randomly assigned to 1 of 12 pens, 3 pens per treatment, to evaluate feedlot performance and carcass characteristics. Dietary treatments were 1) control; 10% roughage, 2) 12% roughage, 3) 14% roughage, and 4) 16% roughage. The digestibility experiment used four ruminally and duodenally cannulated steers (393 ± …

Genetic Parameters, Heterosis, And Breed Effects For Body Condition Score And Mature Cow Weight In Beef Cattle, André Mauric F. Ribeiro, Leticia P. Sanglard, Warren M. Snelling, R. Mark Thallman, Larry A. Kuehn, Matthew L. Spangler

Department of Animal Science: Faculty Publications

Understanding the genetic relationship between mature cow weight (MWT) and body condition score (BCS) is useful to implement selection programs focused on cow efficiency. The objectives of this study were to estimate genetic parameters, heterosis, and breed effects for MWT and BCS. In total, 25,035 and 24,522 overlapping records were available for MWT and BCS on 6,138 and 6,131 cows, respectively, from the Germplasm Evaluation program, a crossbred beef population at the U.S. Meat Animal Research Center. Pedigree was available for 48,013 individuals. Univariate animal models were used to estimate heritabilities for each trait by parity. …

Interaction Of Urea With Frequency And Amount Of Distillers Grains Supplementation For Growing Steers On A High Forage Diet, Haley F. Linder, Josh E. Sebade, Zac E. Carlson, Hannah C. Wilson, Tyler J. Spore, Mary E. Drewnoski, Jim C. Macdonald

Department of Animal Science: Faculty Publications

Two studies were conducted to determine interactions of urea inclusion to a dried distillers grains plus solubles (DDGS; 29.4% crude protein, 5.48% ether extract) supplement fed at two amounts and two frequencies to steers on a high forage diet. In Exp. 1, 120 (247 kg; SD = 20) steers were fed individually for 84 d. Steers received ad libitum grass hay (6.8% crude protein) and one of eight treatments. Treatment design was a 2 × 2 × 2 factorial. Supplement was fed daily or three times per week, amount of supplement fed was 6.36 kg dry matter (DM)/week [0.37% body …

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

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

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

Impact Of Feeding Syngenta Enogen® Feed Corn Compared To Control Corn In Different Diet Scenarios To Finishing Beef Cattle, Stacia M. Volk, Hannah H. Wilson, Kathryn J. Hanford, James C. Macdonald, Galen E. Erickson

Department of Animal Science: Faculty Publications

The objective of this pooled statistical analysis was to evaluate Syngenta Enogen® Feed Corn (EFC) versus conventional corn (CON) when fed as either dry-rolled corn (DRC) or highmoisture corn (HMC) for effects on finishing beef cattle performance and carcass characteristics. Corns were evaluated in diets with byproduct inclusion rates of 0, 15, 18, 20, and 30% distiller grains or 25 and 35% Sweet Bran® (a commercial corn gluten feed product). Seven trials (n = 1856) consisting of 200 pen means comparing 26 diet treatments were analyzed using regression in a pooled analysis. When EFC was processed as DRC, the gain …

Breed And Heterotic Effects For Mature Weight In Beef Cattle, Madeline J. Zimmermann, Larry A. Kuehn, Matthew L. Spangler, R. M. Thallman, Warren M. Snelling, Ronald M. Lewis

Department of Animal Science: Faculty Publications

Cow mature weight (MWT) is heritable and affects the costs and efficiency of a breeding operation. Cow weight is also influenced by the environment, and the relationship between the size and profitability of a cow varies depending on production system. Producers, therefore, need tools to incorporate MWT in their selection of cattle breeds and herd replacements. The objective of this study was to estimate breed and heterotic effects for MWT using weight-age data on crossbred cows. Cow's MWT at 6 yr was predicted from the estimated parameter values-asymptotic weight and maturation constant (k)-from the fit of the Brody function to …

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

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

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

Genetic Parameter Estimates For Bull Prolificacy And Its Relationship With Scrotal Circumference In A Commercial Beef Cattle Population, Chad A. Russell, E John Pollak, Matthew L. Spangler

Department of Animal Science: Faculty Publications

The commercial beef cattle industry relies heavily on the use of natural service sires. When artificial insemination is deemed difficult to implement, multisire breeding pastures are used to increase reproductive rates in large breeding herds or to safe-guard against bull injury during the breeding season. Although each bull might be given an equal opportunity to produce offspring, evidence suggest that there is substantial variation in the number of calves sired by each bull in a breeding pasture. With the use of DNA-based paternity testing, correctly assigning calves to their respective sires in multisire pastures is possible and presents an opportunity …

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

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

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

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

Assessment Of Alternative Models For Genetic Analysis Of Worm And Tick Infestation In Nellore Cattle, T. L. Passafaro, F. B. Lopes, Thomas W. Murphy, B. D. Valente, R. C. Leite, G. J.M. Rosa, F. L.B. Toral

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Worms and ticks are important parasites in beef cattle, especially in tropical areas, causing significant economic and production losses. Understanding animal-to-animal variation on infestation for these parasites might guide genetic selection and improvement of management practices to attenuate its detrimental effects. Statistical models used to analyze such traits usually assume a Gaussian distribution for the observed data. However, this assumption is quite often inappropriate for counting data. Therefore, the objectives of this study were: 1) Estimate genetic parameters for worms and tick infestations in Nellore cattle, and 2) To compare the overall performance of six data analysis approaches for worm …

Genetic Changes In Beef Cow Traits Following Selection For Calving Ease, Gary L. Bennett, Richard M. Thallman, Warren M. Snelling, John W. Keele, Harvey C. Freetly, Larry A. Kuehn

Roman L. Hruska U.S. Meat Animal Research Center: Reports

One approach to reducing calving difficulty is to select heifers with higher breeding value for calving ease. Calving ease is often associated with lower birth weight and that may result in other possible effects on lifetime productivity. Females from experimental select and control calving ease lines within each of the seven populations were compared. Random samples of 720 heifers from lines selected for better calving ease breeding values and 190 heifers from control lines selected for average birth weights were followed through four parities. Select and control lines within the same population were selected to achieve similar yearling weight breeding …

Environmental Conditions And Gas Concentrations In Deep-Pit Finishing Cattle Facilities: A Descriptive Study, Erin L. Cortus, Brian P. Hetchler, Mindy J. Spiehs, Warren Rusche

Roman L. Hruska U.S. Meat Animal Research Center: Reports

There is a lack of data to describe the range of environmental and air quality conditions in beef cattle confinement buildings with deep-pit manure storage. The objective of this article is to describe the environmental conditions, manure nutrient concentrations, and aerial gas concentrations for three deep-pit manure storage finishing beef cattle facilities and varying weather conditions. Measurements were collected from three barns finishing beef cattle with deep pits in Minnesota on three sampling days per barn in summer, fall, and spring weather conditions. The air temperatures throughout the barns closely mirrored the ambient temperature conditions, although significantly lower temperatures were …

Interaction Of Urea With Frequency And Amount Of Distillers Grains Supplementation For Growing Steers On A High Forage Diet, Haley F. Linder

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

Two studies were conducted to determine interactions of urea inclusion to a dried distillers grains plus solubles (DDGS) supplement fed at two amounts and two frequencies to steers on a high forage diet. In Exp. 1, 120 steers were fed individually for 84 d. Steers received ad libitum grass hay and 1 of 8 treatments. Supplement was fed either every day (D) or 3x/week (ALT), amount of supplement fed was 6.36 kg/week (LO) or 12.73 kg/week (HI), and contain either no urea (-U) or 1.3% urea (+U). Hay DMI and steer BW were measured. In Exp. 2, 8 ruminally cannulated …

Improving The Accuracy Of Genomic Predictions: Investigation Of Training Methods And Data Pooling, Johnna Baller

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

One of the primary factors in the response to selection is the accuracy of selection. This study focused on methodologies to predict breeding values (BV) accurately within multi- and single-step genomic evaluations. Factors including cross-validation methods, dependent variables, and genotyping strategies were assessed on the accuracy of genomic BV while using multi-step prediction in real and simulated data. In both cases, random clustering led to largest estimated accuracies compared to clusters based on k-means, k-medoids, and principle component analysis, but differences in bias were not detected. Using deregressed estimated BV (EBV) to estimate SNP effects led to larger accuracies and …

Evaluation Of Protein Utilization In Low And High Protein Forage Sources And The Economic Value Of Supplementing Field Peas (Pisum Sativum) To Growing Cattle Grazing Crested Wheatgrass Pastures, Braden C. Troyer

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

Field peas are widely grown in the panhandle of Nebraska; however, markets quickly become saturated. A two year experiment was conducted comparing field peas to dry distillers grains with solubles (DDGS) as a protein supplement. The objective was to establish a price producers could pay for field peas relative to DDGS. There was a significant difference in ADG due to type of supplement (P = 0.02). Field pea supplemented heifers had 10% lower ADG compared to DDGS supplemented heifers. Economically, this means if DDGS is priced at or $124.58/ 909 kg DM a producer could pay $2.89/ 27 kg, …

Evaluation Of The Effects Of Biochar On Diet Digestibility And Methane Production From Growing And Finishing Steers, Thomas Winders, Melissa L. Jolly, Hannah C. Wilson, James C. Macdonald, Galen E. Erickson, Andrea K. Watson

Department of Animal Science: Faculty Publications

The objectives of these studies were to evaluate the effects of biochar (0%, 0.8%, or 3% of diet dry matter) on diet digestibility and methane and carbon dioxide production from cattle on growing and finishing diets. The growing diet consisted of 21% brome hay, 20% wheat straw, 30% corn silage, 22% wet distillers grains plus solubles, and 7% supplement. The finishing diet consisted of 53% dry-rolled corn, 15% corn silage, 25% wet distillers grains plus solubles, and 7% supplement. In both trials biochar replaced fine ground corn in the supplement. Six crossbred steers (initial body weight [BW] 529 kg; SD …

Comparison Of Different Functions To Describe Growth From Weaning To Maturity In Crossbred Beef Cattle, Madeline J. Zimmermann, Larry A. Kuehn, Matthew L. Spangler, R. Mark Thallman, Warren M. Snelling, Ronald M. Lewis

Department of Animal Science: Faculty Publications

Cow mature weight (MWT) has increased in the past 30 yr. Larger cows cost more to maintain, but their efficiency—and thus profitability— depends on the production environment. Incorporating MWT effectively into selection and mating decisions requires understanding of growth to maturity. The objective of this study was to describe growth to maturity in crossbred beef cattle using Brody, spline, and quadratic functions. Parameter estimates utilized data on crossbred cows from cycle VII and continuous sampling phases of the Germplasm Evaluation Program at the U.S. Meat Animal Research Center. The MWT were estimated at 6 yr from the fitted parameters obtained …

Attainment And Maintenance Of Pubertal Cyclicity May Predict High A4 Cows With Reduced Fertility, Sarah Nafziger

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

Puberty attainment was investigated in heifers. Blood samples were collected from weaning until breeding during 6 years from heifers born in 2012-2017. Plasma progesterone concentrations ≥ 1 ng/ml were used to indicate cyclicity, and heifers were categorized into one of four puberty groups using SAS: 1) Early heifers reached puberty before March 12 and cycled continuously during the sampling period, 2) Typical heifers reached puberty on or after March 12 and cycled continuously, 3) Start-Stop heifers had at least one occurrence of progesterone ≥ 1 ng/ml but discontinued cycling during the sampling period, and 4) Non-Cycling heifers had no occurrence …

Identifying Breed Effects For Cow Mature Weight, Madeline J. Zimmermann

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

Mature weight (MWT) in beef cattle has increased over the past 30 yr. In general, larger cows are costlier to maintain than smaller cows, and their profitability depends on their production environment. A wide range of beef production environments exist in the United States. There are also a variety of beef cattle breeds that can be chosen and mated to create a type of cow which will be optimally suited to excel in a given environment. However, there remains a need for tools allowing effective comparison among breeds to facilitate such decision making. Unfortunately, estimated progeny differences ( …

Evaluation Of Alpha Amylase Containing Corn On Finishing Cattle Performance And Digestibilty, Melissa L. Jolly-Breithaupt

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

One digestion and four finishing trials were conducted to evaluate the effect of a new corn hybrid containing an α-amylase trait, Syngenta Enogen Feed Corn (SYT-EFC) on site and extent of digestion, ruminal fermentation parameters, and feedlot performance. Experiments utilized corn containing the enzymatic gene compared to controls, the near isoline parental corn (NEG) or commercially available corn grain (CON), processed as dry-rolled corn (DRC) or high moisture corn (HMC) in diets with dry [distillers grains plus solubles (DGS)] or wet (Sweet Bran) milling byproducts. The corn grain of the experimental diets were fed as the sole grain source, comprising …

Construction Of A Pen-Scale Methane Collection System And Dietary Strategies For Methane Mitigation From Growing And Finishing Cattle, Thomas Winders

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

Methane production from ruminants has been researched for many years because it has a global warming potential 25x that of carbon dioxide, meaning that mitigating smaller amounts of methane can have a large environmental impact. Research has focused on individual animal methane measurements, but the literature lack in industry-scale measurements. For that reason, the methane barn was built to evaluate dietary strategies on pens of cattle rather than on individual animals. In order to test the methane barn capabilities, an experiment designed to produce differences in methane production was conducted. Cattle received the same growing diet, at either ad-libitum access …

Supplementation And Reproductive Strategies For Beef Females As Part Of A May-Calving Herd In The Nebraska Sandhills, Alicia Caitlin Lansford

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

The objective of these 4 studies was to evaluate the effects of management decisions on reproductive performance of beef females. Experiment 1 evaluated the efficacy of a novel s.c. prostaglandin F_2a injection on estrus synchronization and pregnancy success in yearling beef heifers. Heifers receiving a 2 mL s.c. injection of Lutalyse HighCon had similar estrus response and pregnancy rates compared to 5 mL Lutalyse i.m. within 2 different estrus synchronization programs. In experiment 2, May-calving heifers and primiparous cows were allotted to receive either no supplementation or supplement (0.45 or 0.91 kg/d per animal, heifers or primiparous cows, …

Genome-Wide Association Study For The Relationship Between Temperature And Feed Intake In Beef Cattle, Robel Ghebrewold

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

The interaction of livestock with the environment they live in is complex and plays a significant role in their production performance, which also depends on location and management practices. Climate change is projected to increase temperature globally. As a result, climate change will most likely aggravate the pressure from different sources of stressors on the current agricultural production system in general and in livestock specifically. Environmental conditions, such as changes in ambient temperature, can cause changes in animal behavior and performance. In general, it is believed that as ambient temperature increases, dry matter intake (DMI) of beef cattle decreases. However, …