Sheep and Goat Science Commons^™

Anthelmintic Resistance In Sheep Across Ireland And The Uk: A Literature Review Of The In Vivo Versus In Vitro Methods, Megan Tumulty

SURE_J: Science Undergraduate Research Journal

Background: The animal welfare and production consequences of gastrointestinal nematode infections, namely Nematodirus battus, on sheep are compelling. The control of gastrointestinal infections has been heavily reliant on the administration of anthelmintics since their introduction into mainstream use in 1960. However, their frequent and often excessive use has resulted in anthelmintic resistance being reported extensively in several gastrointestinal nematode species. The prevalence of anthelmintic resistance as well as the increase in the number of cases of multiple-drug resistance in nematode populations now poses substantial hindrance on the viability of sheep production systems. However, despite the threat N. battus poses …

Is There An Economic Advantage To Planting Diverse Summer Annual Forage Mixtures?, Kelly Mercier, Chris Teutsch, Ray Smith, Kenny Burdine, Edwin Ritchey, Eric Vanzant

The Journal of Extension

This study examined economic implications of planting summer annual mixtures of grasses, legumes, and forbs at varying nitrogen rates. No differences in yield occurred between the three mixtures, indicating that mixtures with lowest seed cost will be most economical. Applying N resulted in yield increases of 12.26 lb DM per lb N applied. Although yield responses to N were positive, sensitivity analyses showed that applying N resulted in positive net returns only when hay prices were high and N prices were low. When utilization rates are accounted for, enterprise budgets determined grazing to be 18% cheaper to implement than haying.

Microbial Community Structure From Southern High Plains Beef Cattle Feedyard Manure And Relationship With Nitrous Oxide Emissions, Heidi Waldrip, David Parker, Sierra Miller, Lisa M. Durso, Byeng R. Min, Daniel N. Miller, Kenneth Casey, Bryan Woodbury, Mindy J. Spiehs

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

Modern molecular techniques enable characterization of the microbial biome in livestock manure, from which there is particular concern over emission of greenhouse gases. This study evaluated how sampling depth, time, temperature, and artificial rainfall affected microbial community structure in feedyard manure, and relationships between the manure biome and known parameters related to nitrous oxide (N₂O) emissions. In three large incubation chambers, maintained at different temperatures that received two applications of artificial rainfall, we evaluated manure microbiome composition and abundance of N₂O-producing enzymes (nirK and nirS) using quantitative polymerase chain reaction (qPCR). These data were …

Sheep And Goat Industry Funding Scheme Annual Report 2021/2022, Department Of Primary Industries And Regional Development, Western Australia, Sheep And Goat Industry Funding Scheme

Miscellaneous Publications

No abstract provided.

Weaving An Interdisciplinary Microbiome Career Using Threads From Different Ecosystems, Sarah Hosler

Electronic Theses and Dissertations

Animals have trillions of microorganisms living in or on many body sites, these communities of microorganisms are called microbiomes. Microbiomes are typically host-specific, and a lot of information about the host can be determined from investigating them. Microbiome research has many real-world applications, and this thesis utilizes the One Health perspective, which acknowledges the connection of humans, animals, and environments, and emphasizes the need for collaborative, interdisciplinary research. The first interdisciplinary project is an investigation into the bacteria in wild and cultured Atlantic deep-sea scallop, Placopecten magellanicus larvae. Adults in hatcheries can be induced to spawn, but the last two …

Using Condensed Tannin To Mitigate Tall Fescue Toxicosis, Ally Jo Grote

Graduate Theses and Dissertations

Endophyte-infected (Neotyphodium coenophialum) tall fescue, [Schedonorus arundinaceus (Shreb.)] produces ergot alkaloids. Condensed tannins could bind to ergot alkaloids and render them ineffective. The first objective was to improve the health of sheep offered endophyte-infected tall fescue by binding toxins in the rumen with condensed tannins. Non-toxic novel-endophyte infected tall fescue (NE) or toxic endophyte-infected tall fescue forage was harvested, baled at targeted moisture of 55%, wrapped within 8 hours of baling with 2 layers of net wrap and 20 layers of plastic, and ensiled for at least 60 days. Prior to feeding, forages were chopped and packed into plastic trash …

Evaluating The Shelf Life And Sensory Properties Of Beef Steaks From Cattle Raised On Different Grass Feeding Systems In The Western United States, Toni L. Duarte, Bakytzhan Bolkenov, Sarah C. Klopatek, James W. Oltjen, D. Andy King, Steven D. Shackelford, Tommy L. Wheeler, Xiang Yang

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

Consumer interest in grass-fed beef has been steadily rising due to consumer perception of its potential benefits. This interest has led to a growing demand for niche market beef, particularly in the western United States. Therefore, the objective of this study was to assess the impact of feeding systems on the change in microbial counts, color, and lipid oxidation of steaks during retail display, and on their sensory attributes. The systems included: conventional grain-fed (CON), 20 months-grass-fed (20GF), 25-months-grass-fed (25GF) and 20-months-grass-fed + 45-day-grain-fed (45GR). The results indicate that steaks in the 20GF group displayed a darker lean and fat …

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

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 …

Prenatal Transportation Stress Did Not Impact Ovarian Follicle Count For Three Generations Of Female Brahman Offspring, Lacey K. Quail, Ronald D. Randel, Thomas H. Welsh Jr., Robert A. Cushman, Hannah K. Yake, Rui A. D'Orey Branco, Donald A. Neuendorff, Charles R. Long, George A. Perry

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

As prenatal transportation stress altered behavior and adrenal glucocorticoid secretion of calves, we hypothesized that prenatal transportation stress would decrease ovarian reserve size and negatively impact female offspring fertility. The impact of prenatal transportation stress on ovarian follicle numbers in female offspring for three generations was studied. Brahman cows were transported for 2 h on day 60 ± 5, 80 ± 5, 100 ± 5, 120 ± 5, and 140 ± 5 of gestation. Ovaries were collected from offspring of transported or non-transported dams at multiple ages. Primordial, primary, secondary, and antral follicles were histologically analyzed. Antral follicle numbers were …

Efficacy Of Antimicrobial Interventions Used In Meat Processing Plants Against Antimicrobial Tolerant Non–Antibiotic-Resistant And Antibiotic-Resistant Salmonella On Fresh Beef, Norasak Kalchayanand, Sapna Chitlapilly Dass, Yangjunna Zhang, Eric L. Oliver, Bing Wang, Tommy L. Wheeler

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

Salmonella is a common cause of foodborne illness in the United States, and several strains of Salmonella have been identified as resistant to antibiotics. It is not known whether strains that are antibiotic resistant (ABR) and that have some tolerance to antimicrobial compounds are also able to resist the inactivation effects of antimicrobial interventions used in fresh meat processing. Sixty-eight Salmonella isolates (non-ABR and ABR strains) were treated with half concentrations of lactic acid (LA), peracetic acid (PAA), and cetylpyridinium chloride (CPC), which are used in beef processing plants to screen for tolerant strains. Six strains each from non-ABR and …

Effects Of Administration Of A Growth Promoting Implant During The Suckling Phase Or At Weaning On Growth, Reproduction, And Ovarian Development In Replacement Heifers Grazing Native Range, Shelby L. Rosasco, Emily A. Melchior-Tiffany, Cierrah J. Kassetas, Shad H. Cox, Richard L. Dunlap, Jennifer A. Hernandez Gifford, Eric J. Scholljegerdes, Robert A. Cushman, Adam F. Summers

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

Management strategies utilized during pre-breeding development of replacement heifers can impact fertility and the ovarian reserve. Angus- Hereford crossbred heifers (n = 233) were utilized over a 3-yr period to determine the effects of administration of a growth promoting implant at either branding or weaning on growth, reproduction, and ovarian development. Heifer calves were randomly assigned to one of three treatments: 1) nonimplanted controls (CON; n = 79), 2) implanted at approximately 2 mo of age (average calf age = 58 d) with Synovex-C (BIMP, n = 82), or 3) implanted at approximately 7 mo of age (average calf …

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

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 …

Assessing The Microbiological Profile Of Raw Goat Milk And Understanding Producer Practices And Perceptions, Jacinda Skye Leopard

Theses and Dissertations

Raw milk sales are legal in 30 states, including Mississippi, where regulations are largely management-based and not food-safety related. The research objectives were to analyze the microbial profile of raw goat milk from Mississippi farms and assess food safety practices and perceptions of dairy goat farmers. Deficiencies and opportunities for improvement in raw goat milk safety were identified. Staphylococcus spp. was present in most (70%) milk samples but aligned with drying-off. E. coli, Enterobacteriaceae, and coliforms were observed in 4, 10, and 12 samples, respectively; no Salmonella spp. or Listeria monocytogenes were detected. The survey highlighted farmers' need for …

Development And Validation Of High-Resolution Melting Assays For The Detection Of Potentially Virulent Strains Of Escherichia Coli O103 And O121, Frank J. Velez, Joseph M. Bosilevac, Sabine Delannoy, Patrick Fach, Ravinder Nagpal, Prashant Singh

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

Virulent strains of Shiga toxin-producing Escherichia coli (STEC) serogroups O103 and O121 are considered adulterants in beef. Two high-resolution melting (HRM) real-time PCR assays were standardized for the specific detection and discrimination of potentially virulent and avirulent strains of E. coli O103 and O121. The O103 HRM assay offered the possibility to distinguish clearly STEC O103:H2 from STEC O103:H25. The two standardized assays were extensively validated using 215 pure culture strains, laboratory inoculated food samples, and naturally contaminated beef (n = 84) and pork (n = 84) enrichments collected from the red meat surveillance program. Both HRM assays showed 100% …

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

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 ± …

Oestrogenic Subterranean Clover Guide. Identification And Remediation, Kevin J. Foster, Megan H. Ryan, Daniel R. Kidd

Bulletins 4000 -

Subterranean clover (subclover, Trifolium subterraneum L.) is an annual pasture legume that provides high quality feed for livestock. It is estimated to be sown over 30 million hectares across southern Australia, with cultivars developed for the low, medium and high rainfall zones. Unfortunately, some older cultivars contain high levels of phytoestrogen which can affect the reproductive system of sheep and cause other health issues. This became a significant issue for sheep producers from the 1940s as new land was cleared and sheep grazed subclover-dominant pastures. There was a collection of livestock issues observed and these were grouped together under the …

The Effects Of Poor Maternal Nutrition During Gestation In Sheep On The Reproductive Efficiency Of The Offspring, Morgan Dougherty

Honors Scholar Theses

Poor maternal nutrition during gestation negatively impacts fetal programming and the development of the hypothalamic-pituitary-ovarian axis in the offspring. Reproductive health of ewes can be characterized by concentrations of reproductive hormones including follicle stimulating hormone (FSH), luteinizing hormone (LH), and progesterone, particularly during the estrous cycle. We hypothesized that ewes born to dams that experienced poor maternal nutrition during gestation would have reduced reproductive capability and efficiency. This means that they would take longer to become pregnant and have reduced concentrations of reproductive hormones compared with those born to mothers fed the control diet. Pregnant dams (F0) were fed one …

Evaluation Relativity Variation And Some Minerals Concentration During Lactation Stage Of Syrian Mountains Goat Milk Under Grazing System, تقدير التغيرات النسبية ومستوى تراكيز بعض المعادن خلال مرحلة إنتاج حليب الماعز الجبلي السوري تحت نظام الرعاية السرحي, Osama Diab, Samuel Mossa, Shehadeh Qaskos

Arab Journal of Arid Environments المجلة العربية للبيئات الجافة

The aim of this study was to investigate the effect of lactation stage on chemical composition and some minerals concentration of Syrian mountains Goat milk using grazing system in Al-Quneitera area (Syria) in year 2013. Twenty mountains Syrian goats were used to evaluate milk production and composition (fat, protein, lactose, and non-fat solids) and some minerals concentration (Ca, P, Na, K, Cu, Mg, Mn, Fe, Zn, cl) during lactation. Using SPSS program, data were analyzed by ANOVA with repeated measures. Daily milk yield was 1473.1 ± 297.42 g/head, while the total milk was 342.02 ± 135.6 Kg/head. The results of …

Wc1 And Tcr Interactions For Γδ T Cell Activation, Alexandria Gillespie

Doctoral Dissertations

Major subpopulations of gamma delta T cells within ruminant and pigs are defined by expression of WC1, a hybrid pattern recognition receptor/co-receptor to the T cell receptor (TCR). It is known that when WC1 is knocked down cells fail to respond. Showing that WC1 plays an active role in the stimulation of bovine gamma delta T cells. Here we explored the spatio-temporal dynamics of WC1 and TCR interaction using imaging flow cytometry and stochastic optical reconstruction microscopy. We found that in quiescent gamma delta T cells both WC1 and TCR existed in separate protein domains (protein islands) but after activation …

Greater Numbers Of Antral Follicles In The Ovary Are Associated With Increased Concentrations Of Glucose In Uterine Luminal Fluid Of Beef Heifers, Alexandria P. Snider, Matthew S. Crouse, Shelby L. Rosasco, Kaitlin M. Epperson, Emmalee J. Northrop-Albrecht, Jerica J.J. Rich, Chadwick C. Chase Jr., Jeremy R. Miles, George A. Perry, Adam F. Summers, Robert A. Cushman

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

Increased antral follicles are associated with greater fertility and a uterine environment that is more supportive of early embryonic development in beef heifers. Glucose is a primary energy source for embryos, and glucose concentrations are elevated in uterine luminal fluid (ULF) of pregnant heifers. We hypothesized that ULF glucose concentrations and endometrial transcript abundance for glucose transporters on d16 after insemination would be greater in heifers with increased numbers of antral follicles. Heifers classified with either increased or diminished antral follicle counts were artificially inseminated following the CO-Synch protocol (d0). On d16 after insemination, reproductive tracts of heifers were collected …

Proteomic Analyses Identify Differences Between Bovine Epididymal And Ejaculated Spermatozoa That Contribute To Longevity, Saulo Menegatti Zoca, Emmalee J. Northrop-Albrecht, Julie A. Walker, Robert A. Cushman, George A. Perry

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

Sperm are stored for extended periods of time in the epididymis, but upon ejaculation motility is increased and lifespan is decreased. The objective of this study was to identify differences in proteins between epididymis and ejaculated samples that are associated with longevity. Ejaculated semen was collected from mature Angus bulls (n = 9); bulls were slaughtered and epididymal semen was collected. Epididymal and ejaculated semen were centrifuged to separate sperm and fluid. Fluids were removed and sperm pellets were resuspended in a high ionic solution and vortexed to remove loosely attached proteins. Sperm samples were centrifuged, and the supernatant was …

Greenhouse Gas Emissions And Animal Protein For Human Consumption., Homero Salinas

Title III Professional Development Reports

Livestock is a key to nutrition and food security. Livestock is key to livelihoods, and it is calculated that there are 400 million poor animal keepers.

There are two indicators of gas emissions. One is the GDP in $US per ton of CO2e, and the other is the gobs created per ton of CO2e. For this presentation, the comparison of interest is agriculture vs. other productive activities. So, at the broad word level, around 300% more GDP is produced from other goods than from agricultural goods per ton of CO2e. Even in high-income countries, there is 700% more GDP/CO2e than …

Effects Of Harvest Season On Carcass Characteristics Of Lambs In The Intermountain West, J. R. Whaley, T. W. Murphy, C. L. Gifford, W. J. Means, J. P. Ritten, H. N. Mckibben, C. M. Page, W. C. Stewart

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

Objective: The objectives of this study were to survey characteristics including hot carcass weight (HCW), 12th rib fat thickness (RFT), body-wall thickness (BWT), longissimus muscle area (LMA), USDA yield grade (USDA YG), percentage closely trimmed retail cuts (RC), and calculated yield grade (Calc YG) of lamb carcasses in the Intermountain West to determine the effects of season of slaughter and interrelationships among carcass characteristics.

Materials and Methods: Lamb carcass characteristics were evaluated in 2 commercial Intermountain West processing plants over one year (n = 10,027). Carcasses were evaluated by season: spring (December–April, n = 2,322) and summer (May–August, n …

Effects Of Increasing Dietary Zinc Sulfate Fed To Gestating Ewes: Ii. Milk Somatic Cell Count, Microbial Populations, And Fatty Acid Composition, C. M. Page, R. M. Knuth, T. W. Murphy, D. C. Rule, B. Bisha, J. B. Taylor, W. C. Stewart

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

Objective: The objective of the research was to evaluate the effects of increasing dietary Zn sulfate concentration for primiparous gestating ewes on subsequent milk SCC, intramammary microbial identifications, and fatty acid composition.

Materials and Methods: Commercial white-face (WF; n = 27) and black-face (BF; n = 24) ewes (age ≈18 mo; BW = 87.48 ± 8.37 kg) were sorted into breed-type groups and within groups ranked by BW, and then, they were randomly divided into 3 dietary supplement treatment groups: CON (n = 13; 40 mg/kg Zn; ≈1 × NASEM recommendations), Zn500 (n = 21; 500 mg/kg Zn; …

Using Acid-Detergent Insoluble Ash As An Internal Marker To Compare Digestibility And Fecal Output By Ovine That Were Offered Hays Of Varying Nutrient Composition, Kennedy Barnett, Trisha Adams, Kenneth P. Coffey, Kathleen S. Jogan

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Digestibility markers are used to determine total digestibility without collecting total feces, which reduces time and labor and allows greater numbers of animal observations to be obtained. The goal was to determine if the digestibility marker acid detergent insoluble ash (ADIA) was fully recovered, and based on that information, determine the accuracy of total digestion predictions using ADIA. Different proportions of sericea lespedeza hay and alfalfa silage were offered to 16 gestating Dorper ewe lambs (Ovis aries) (41.8 ± 4.61 kg body weight) to determine digestibility. Total feed intake and fecal excretion were measured during 2 experimental periods consisting of …

Evaluation Of Salmonella Biofilm Cell Transfer From Common Food Contact Surfaces To Beef Products, Rong Wong, David A. King, Norasak Kalchayanand

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

Meat contamination by Salmonella enterica is a serious public health concern. Available data have suggested that biofilm formation at processing plants and contaminated contact surfaces might contribute to meat contamination. Because transfer from contact surfaces to food products via direct contact has been deemed the most common bacteria transmission route that can lead to contamination, we evaluated the effect of Salmonella biofilm forming ability, contact surface material, and beef surface tissue type on Salmonella biofilm transfer from hard surfaces to beef products. Salmonella biofilms developed on the common contact surfaces stainless steel (SS) and polyvinylchloride (PVC) were transferred consecutively via …

Hotline Number To Reach And Offer Agricultural Information To Plain Anabaptists During The Covid-19 Workplace Closures, Emily Shoop, Carly Becker, Nathan Glenn Briggs, Danielle Smarsh

Journal of Amish and Plain Anabaptist Studies

The Penn State Extension Animal Systems Team developed a toll-free hotline phone number to convey short educational messages to maintain contact and outreach to Pennsylvania’s animal producing Amish, Mennonite, and other plain Anabaptist populations. During the COVID-19 pandemic, Penn State Extension’s programming went largely online via webinars, online courses, and emails. This change in programming excluded a large sector of Pennsylvania farmers who do not use or have access to the internet and, as such, were liable to miss important best management practice reviews and timely updates in animal agriculture. The Animal Systems Hotline offered callers the choice to listen …

Is There Room In The United States Diet For Goat Meat? Analysis Of The 2019 National Goat Meat Survey, Everett Marcus Martin

MSU Graduate Theses

Demand for goat meat has steadily increased in the past decade, but few studies have been conducted addressing goat meat attributes and demographic factors on consumers’ willingness to buy goat meat products. Analyzing a national consumer survey on goat meat preference, a logit modeling is used addressing factors affecting willingness to buy three goat meat products: grass-fed, locally grown, and organically raised. Results indicate that quality and freshness attribute characteristics significantly affect consumer willingness to buy grass-fed, organic, and locally grown goat meat.

Considerations And Best Practices In Animal Science 16s Ribosomal Rna Gene Sequencing Microbiome Studies, Margaret D. Weinroth, Aeriel D. Belk, Chris Dean, Noelle Noyes, Dana K. Dittoe, Michael J. Rothrock Jr, Steven C. Ricke, Phillip R. Myer, Madison T. Henniger, Gustavo A. Ramírez, Brian B. Oakley, Katie Lynn Summers, Asha M. Miles, Taylor B. Ault-Seay, Zhongtang Yu, Jessica L. Metcalf, James E. Wells

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

Microbiome studies in animal science using 16S rRNA gene sequencing have become increasingly common in recent years as sequencing costs continue to fall and bioinformatic tools become more powerful and user-friendly. The combination of molecular biology, microbiology, microbial ecology, computer science, and bioinformatics—in addition to the traditional considerations when conducting an animal science study—makes microbiome studies sometimes intimidating due to the intersection of different fields. The objective of this review is to serve as a jumping-off point for those animal scientists less familiar with 16S rRNA gene sequencing and analyses and to bring up common issues and concerns that arise …

Twenty-Four-Month Longitudinal Study Suggests Little To No Horizontal Gene Transfer In Situ Between Third-Generation Cephalosporin-Resistant Salmonella And Third-Generation Cephalosporin-Resistant Escherichia Coli In A Beef Cattle Feedyard, John W. Schmidt, Sarah A. Murray, Aaron M. Dickey, Tommy L. Wheeler, Dayna M. Harhay, Terrance M. Arthur

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

Third-generation cephalosporins (3GCs) are preferred treatments for serious human Salmonella enterica infections. Beef cattle are suspected to contribute to human 3GC-resistant Salmonella infections. Commensal 3GC-resistant Escherichia coli are thought to act as reservoirs of 3GC resistance because these strains are isolated more frequently than are 3GC-resistant Salmonella strains at beef cattle feedyards. During each of 24 consecutive months, four samples of pen surface material were obtained from five pens (N = 480) at a Nebraska feedyard to determine to the contribution of 3GC-resistant E. coli to the occurrence of 3GC-resistant Salmonella. Illumina whole genome sequencing was performed, and …