Terrestrial and Aquatic Ecology Commons^™

Gulls As Sources Of Environmental Contamination By Colistin-Resistant Bacteria, Alan B. Franklin, Andrew M. Ramey, Kevin T. Bentler, Nicole L. Barrett, Loredana M. Mccurdy, Christina A. Ahlstrom, Jonas Bonnedahl, Susan A. Shriner, Jeffrey C. Chandler

United States Department of Agriculture Wildlife Services: Staff Publications

In 2015, the mcr-1 gene was discovered in Escherichia coli in domestic swine in China that conferred resistance to colistin, an antibiotic of last resort used in treating multi-drug resistant bacterial infections in humans. Since then, mcr-1 was found in other human and animal populations, including wild gulls. Because gulls could disseminate the mcr-1 gene, we conducted an experiment to assess whether gulls are readily colonized with mcr-1 positive E. coli, their shedding patterns, transmission among conspecifics, and environmental deposition. Shedding of mcr-1 E. coli by small gull flocks followed a lognormal curve and gulls shed one strain >101 …

Piscivorous Bird Use Of Aquaculture And Natural Water Bodies In Mississippi, Paul C. Burr, Jimmy I. Avery, Garrett M. Street, Bronson K. Strickland, Brian S. Dorr

United States Department of Agriculture Wildlife Services: Staff Publications

Double crested cormorants (Phalacrocorax auritus) and great egrets (Ardea alba) have an extensive history of human wildlife conflict with the aquaculture industry of western Mississippi, USA, due to

their depredation of cultured catfish (Ictalurus spp.). Although aquaculture is abundant, western Mississippi also contains naturally occurring water bodies that offer alternative forage opportunities to these species. How cormorants or egrets distribute themselves among these 2 foraging options is unknown, but it has been generally assumed each species uses aquaculture disproportionately more because of the high density of available prey. To test this assumption, we surveyed these …

Control Or Eradication: Problems In The Management Of Invasive Birds, Michael L. Avery, Chris J. Feare

United States Department of Agriculture Wildlife Services: Staff Publications

Humans have captured, transported and intentionally released wild birds for centuries (Blackburn et al., 2009). Motivations for such purposeful introductions include food (West and Zhou, 2007), religion (Agoramoorthy and Hsu, 2007), sport (McDowall, 1994), biocontrol (Bennett and Hughes, 1959; Kurdila, 1995) and aesthetics (Ryan, 1906; Thomson, 1922). Many purposeful bird introductions were the work of acclimatization societies, particularly in North America, New Zealand and Australia. These societies were formed in the 19th century by European settlers to transport bird species from their homelands in efforts to establish them in the newly settled regions (Thomson, 1922; Dunlap, 1997). As a result …

Biotic And Abiotic Factors Influencing Arsenic Biogeochemistry And Toxicity In Fluvial Ecosystems: A Review, Laura Barral-Fraga, María Teresa Barral, Keeley L. Macneill, Diego Martiñá-Prieto, Soizic Morin, María Carolina Rodríguez-Castro, Baigal-Amar Tuulaikhuu, Helena Guasch

School of Natural Resources: Faculty Publications

This review is focused on the biogeochemistry of arsenic in freshwaters and, especially, on the key role that benthic microalgae and prokaryotic communities from biofilms play together in through speciation, distribution, and cycling. These microorganisms incorporate the dominant iAs (inorganic arsenic) form and may transform it to other arsenic forms through metabolic or detoxifying processes. These transformations have a big impact on the environmental behavior of arsenic because different chemical forms exhibit differences in mobility and toxicity. Moreover, exposure to toxicants may alter the physiology and structure of biofilms, leading to changes in ecosystem function and trophic relations. In this …

Distribution, Density, Movement, And Support For Management Of Mountain Sucker, Pantosteus Jordani, In The Black Hills Of South Dakota, Seth J. Fopma

Electronic Theses and Dissertations

Mountain Sucker, Pantosteus jordani, is a cold-water species native to the Intermountain West. Fringe populations of Mountain Sucker have experienced declines in recent decades. The population of Mountain Sucker found in the Black Hills of South Dakota represents the eastern fringe of the species’ native range. Recognized as both an indicator of biologic health and as a species of greatest conservation need in South Dakota, recent studies have suggested significant declines in both distribution and abundance. Despite the recent study of Mountain Sucker in the region, increased understanding of Mountain Sucker ecology is needed to effectively manage for the conservation …

Influence Of Mink Predation On Brown Trout Survival And Size-Structure In Rapid Creek, South Dakota, Austin Galinat

Electronic Theses and Dissertations

I compared movement, home range, habitat selection, and mortality among radio-tagged Brown Trout (Salmo trutta) at an American Mink (Neovison vison)-removal site, improved habitat site, and an undisturbed stream site in Rapid Creek, South Dakota. I observed high, post-surgery (> 26 days) survival rate (90%) of radio tagged Brown Trout. Average gross movement of Brown Trout was greater at the improved habitat site (127 m) compared to the mink removal (31 m) site, while average home range size (i.e., stream distance) among all three sites was not significantly different indicating strong site fidelity (125 to 200 m). Brown Trout movements …

Evaluation Of Fall-Seeded Cover Crops For Grassland Nesting Waterfowl In Eastern South Dakota, Charles W. Gallman Iii

Electronic Theses and Dissertations

The Prairie Pothole Region is the primary breeding ground for many species of North American waterfowl. This landscape was historically dominated by mixed and tallgrass prairies interspersed with wetlands, but >70% of native grassland area has been lost due to widespread conversion to croplands, which may threaten waterfowl production. Cover cropping is a re-emerging farming technique that may provide suitable nesting cover for grassland nesting waterfowl on active farmlands. My research objectives were to evaluate the utility of fall-seeded cover crops to breeding waterfowl compared to perennial cover, determine if cover crops in rotation with row crops can successfully support …

Agri-Combs: Open-Path Dual-Comb Spectroscopy Of Livestock Emissions, D. I. Herman, L. C. Hutcherson, C. Weerasekara Et Al.

School of Natural Resources: Documents and Reviews

No abstract provided.

Winter Patch Grazing, Patch Burn Grazing, And Bird Communities In Western South Dakota, Jennifer Lutze

Electronic Theses and Dissertations

Ground nesting bird species are on a considerable decline and research efforts are being made to increase these populations throughout the Great Plains. Ground nesting bird communities found in the Northern Great Plains are driven greatly by varying amounts of cover and area size. Past research implemented patch-burn grazing to increase structural heterogeneity and to increase grassland bird habitat in the tallgrass prairie. While bird populations were very responsive to this management in the Northern Great Plains fire management is viewed negatively, especially for Midwest cattle ranchers. We implemented research to determine if winter-patch grazing on mixed grass prairie could …

Mixed Ancestry From Wild And Domestic Lineages Contributes To The Rapid Expansion Of Invasive Feral Swine, Timothy J. Smyser, Michael A. Tabak, Chris Slootmaker, Michael S. Robeson Ii, Ryan S. Miller, Mirte Bosse, Hendrik-Jan Megens, Martien A.M. Groenen, Samuel Rezende Paiva, Danielle Assis De Faria, Harvey D. Blackburn, Brandon S. Schmit, Antoinette J. Piaggio

United States Department of Agriculture Wildlife Services: Staff Publications

Invasive alien species are a significant threat to both economic and ecological systems. Identifying the processes that give rise to invasive populations is essential for implementing effective control strategies. We conducted an ancestry analysis of invasive feral swine (Sus scrofa, Linnaeus, 1758), a highly destructive ungulate that is widely distributed throughout the contiguous United States, to describe introduction pathways, sources of newly emergent populations and processes contributing to an ongoing invasion. Comparisons of high-density single nucleotide polymorphism genotypes for 6,566 invasive feral swine to a comprehensive reference set of S. scrofa revealed that the vast majority of feral swine were …

The Role Of European Starlings (Sturnus Vulgaris) In The Dissemination Of Multidrug- Resistant Escherichia Coli Among Concentrated Animal Feeding Operations, Jeffrey C. Chandler, Jennifer E. Anders, Nicolas A. Blouin, James C. Carlson, Jeffrey T. Lejeune, Lawrence D. Goodridge, Baolin Wang, Leslie A. Day, Anna M. Mangan, Dustin A. Reid, Shannon M. Coleman, Matthew W. Hopken, Bledar Bisha

United States Department of Agriculture Wildlife Services: Staff Publications

Antimicrobial use in livestock production is a driver for the development and proliferation of antimicrobial resistance (AMR). Wildlife interactions with livestock, acquiring associated AMR bacteria and genes, and wildlife’s subsequent dispersal across the landscape are hypothesized to play an important role in the ecology of AMR. Here, we examined priority AMR phenotypes and genotypes of Escherichia coli isolated from the gastrointestinal tracts of european starlings (Sturnus vulgaris) found on concentrated animal feeding operations (CAFOs). European starlings may be present in high numbers on cAfos (>100,000 birds), interact with urban environments, and can migrate distances exceeding 1,500 km in North …

Reporting The Limits Of Detection And Quantification For Environmental Dna Assays, Katy E. Klymus, Christopher M. Merkes, Michael J. Allison, Caren S. Goldberg, Caren C. Helbing, Margaret E. Hunter, Craig A. Jackson, Richard F. Lance, Anna M. Mangan, Emy M. Monroe, Antoinette J. Piaggio, Joel P. Stokdyk, Chris C. Wilson, Catherine A. Richter

United States Department of Agriculture Wildlife Services: Staff Publications

Background: Environmental DNA (eDNA) analysis is increasingly being used to detect the presence and relative abundance of rare species, especially invasive or imperiled aquatic species. The rapid progress in the eDNA field has resulted in numerous studies impacting conservation and management actions. However, standardization of eDNA methods and reporting across the field is yet to be fully established, with one area being the calculation and interpretation of assay limit of detection (LOD) and limit of quantification (LOQ).

Aims: Here, we propose establishing consistent methods for determining and reporting of LOD and LOQ for single‐species quantitative PCR (qPCR) eDNA studies.

Materials …

Safety, Immunogenicity, And Efficacy Of Intramuscular And Oral Delivery Of Era-G333 Recombinant Rabies Virus Vaccine To Big Brown Bats (Eptesicus Fuscus), Amy T. Gilbert, Xianfu Wu, Felix R. Jackson, Richard Franka, Gary F. Mccracken, Charles E. Rupprecht

United States Department of Agriculture Wildlife Services: Staff Publications

Attenuated strains of rabies virus (RABV) have been used for oral vaccination of wild carnivores in Europe and North America. However, some RABV vaccines caused clinical rabies in target animals. To improve the safety of attenuated RABV as an oral vaccine for field use, strategies using selection of escape mutants under monoclonal antibody neutralization pressure and reverse genetics–defined mutations have been used. We tested the safety, immunogenicity, and efficacy of one RABV construct, ERA-g333, developed with reverse genetics by intramuscular (IM) or oral (PO) routes in big brown bats (Eptesicus fuscus). Twenty-five bats received 5×10⁶ mouse intracerebral …

Psychological Drivers Of Risk-Reducing Behaviors To Limit Human–Wildlife Conflict, Stacy A. Lischka, Tara L. Teel, Heather E. Johnson, Courtney Larson, Stewart Breck, Kevin R. Crooks

United States Department of Agriculture Wildlife Services: Staff Publications

Conflicts between people and wild animals are increasing globally, often with serious consequences

for both. Local regulations or ordinances are frequently used to promote human behaviors that minimize these conflicts (risk-reducing behaviors), but compliance with ordinances can be highly variable. While efforts to increase compliance could be improved through applications of conservation psychology, little is known about the relative influence of different factors motivating compliance. Using concepts from psychology and risk theory, we conducted a longitudinal study pairing data from mail surveys with direct observations of compliance with a wildlife ordinance requiring residents to secure residential garbage from black bears …

Timing And Extent Of Crop Damage By Wild Pigs (Sus Scrofa Linnaeus) To Corn And Peanut Fields, C. M. Boyce, Kurt C. Vercauteren, James C. Beasley

United States Department of Agriculture Wildlife Services: Staff Publications

The global expansion of wild pigs over the last few decades has resulted in an increase in extent and distribution of damages to crops, placing a growing strain on agricultural producers and land managers. Despite the extent of wild pig damage to agriculture, there is little data regarding timing and spatial variability of damage to corn (Zea mays Linnaeus) and we found no data regarding the effect of these factors on peanuts (Arachis hypogaea Linnaeus). Our objective was to determine the timing and extent of wild pig damage to corn and peanut fields, as well as the extent …

Validation Of A Screening Method For The Detection Of Colistin-Resistant E. Coli Containing Mcr-1 In Feral Swine Feces, Jeffrey C. Chandler, Alan B. Franklin, S. N. Bevins, Kevin T. Bentler, Jonas Bonnedahl, Christina A. Ahlstrom, Bledar Bisha, Susan A. Shriner

United States Department of Agriculture Wildlife Services: Staff Publications

A method was developed and validated for the detection of colistin-resistant Escherichia coli containing mcr-1 in the feces of feral swine. Following optimization of an enrichment method using EC broth supplemented with colistin (1 μg/mL) and vancomycin (8 μg/mL), aliquots derived from 100 feral swine fecal samples were spiked with of one of five different mcr-1 positive E. coli strains (between 10⁰ and 10⁴ CFU/g), for a total of 1110 samples tested. Enrichments were then screened using a simple boil-prep and a previously developed real-time PCR assay for mcr-1 detection. The sensitivity of the method was determined in …

Cattle Egrets Regurgitate House Mouse Carcasses Onto A Mouse-Free Island: Implications For Rodent Eradications, Aaron B. Shiels, Mele Khalsa, Doreen L. Griffin, Clay K. Chow, Sheri S. Mann, Antoinette J. Piaggio

United States Department of Agriculture Wildlife Services: Staff Publications

Context. Eradication of invasive rodents on islands typically results in positive conservation gains, and maintaining a rodent-free island requires elevated biosecurity, including prevention of assisted rodent arrival via watercraft, aircraft and animals such as birds. Cattle egrets (Bubulcus ibis) are widespread, and often fly several kilometres daily to roost and forage. They frequently swallow insects and vertebrates (including rodents) whole, and some regurgitate prey. Cattle egrets have been regularly observed flying between the Hawaiian Islands of Ni’ihau (where non-native mice and rats are established) and Lehua (where one species of non-native rat is established and was targeted during …

Competing Reproductive And Physiological Investments In An All‑Female Lizard, The Colorado Checkered Whiptail, Lise M. Aubry, Spencer B. Hudson, Bryan M. Kluever, Alison C. Webb, Susannah S. French

United States Department of Agriculture Wildlife Services: Staff Publications

Organisms in the wild have to allocate limited resources towards competing functions such as reproduction, growth, and self-maintenance. These competing investments create significant changes in physiological activity, and we still know little about the relationship between physiological activity and reproductive investment in natura. We investigated trade-offs between physiological activity and reproductive investment in the parthenogenetic Colorado checkered whiptail, Aspidoscelis neotesselata, across three different sites at the US Army Fort Carson Military Installation near Colorado Springs, CO, through-out the reproductive season in 2018 and 2019. We measured clutch size and reproductive activity and quantified plasma corticosterone (CORT), reactive oxygen metabolites (ROMs), …

Monk Parakeet (Myiopsitta Monarchus Boddaert, 1783), Michael L. Avery

United States Department of Agriculture Wildlife Services: Staff Publications

Common Names: Monk Parakeet, Quaker Parakeet, Quaker Parrot, Quaker Conure, Grey-headed Parakeet

The natural distribution of the Monk Parakeet (Myiopsitta monachus Boddaert, 1783) extends from southern Bolivia, through Paraguay, southern Brazil and Uruguay to southern Argentina (Fig. 10.1 ). It is documented as invasive in a range of countries, and of these, there are at least 17 countries where they are breeding in the wild, as detailed below. ...

The Monk Parakeet is among the most successful invasive bird species in the world. Unlike many other invasive birds, such as the Ring-necked Parakeet (Psittacula krameri) and the …

Movement Behavior Of Radio-Tagged European Starlings In Urban, Rural, And Exurban Landscapes, Page E. Klug, H. Jeffrey Homan

United States Department of Agriculture Wildlife Services: Staff Publications

Since their intentional introduction into the United States in the 1800s, European starlings (Sturnus vulgaris) have become the fourth most common bird species and a nuisance bird pest in both urban and rural areas. Managers require better information about starling movement and habit-use patterns to effectively manage starling populations and the damage they cause. Thus, we revisited 6 radio-telemetry studies conducted during fall or winter between 2005 and 2010 to compare starling movements (n = 63 birds) and habitat use in 3 landscapes. Switching of roosting and foraging sites in habitat-sparse rural landscapes caused daytime (0900–1500 hours) …

Serum Chemistry Values In Wild Black Vultures In Mississippi, Usa, Fred L. Cunningham, Sherman W. Jack, Amanda R. Deese, Eric R. Wengert, Kyle Van Why, Carla L. Huston, Scott Lemmons, Richard B. Minnis

United States Department of Agriculture Wildlife Services: Staff Publications

Vultures (Cathartidae and Accipitridae) play an important role in ecosystem balance by rapidly disposing animal carcasses and thus preventing the potential spread of pathogens. Blood chemistry values provide a means of assessing the health of wildlife and wild animal populations; however, there are significant differences in chemistries among species and when comparing captive and free-living New and Old World vultures. In 2007, we collected blood serum from 30 female and 14 male wild, healthy black vultures (Coragyps atratus) live-trapped by the U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services from a power substation in …

One Step Closer To A Better Starling Trap, James R. Thiele

United States Department of Agriculture Wildlife Services: Staff Publications

European starlings (Sturnus vulgaris) are an invasive species in the United States that damage agriculture, personal property, and threaten human health and safety. The U.S. Department of Agriculture Wildlife Services provides technical support to mitigate damage by controlling starling populations at concentrated animal feeding operations, landfills, utilities, and urban areas. Wildlife Services uses DRC-1339, a registered toxicant, to reduce starling populations. Trapping can also be an effective tool but requires more time at a higher cost than DRC-1339. Trapping starlings, however, may be needed to provide a viable alternative to mitigate damage in areas where toxicant use may …

Invasive Wild Pigs As Primary Nest Predators For Wild Turkeys, Heather N. Sanders, David G. Hewitt, Humberto L. Perotto-Baldivieso, Kurt C. Vercauteren, Nathan P. Snow

United States Department of Agriculture Wildlife Services: Staff Publications

Depredation of wild turkey (Meleagris gallopavo) nests is a leading cause of reduced recruitment for the recovering and iconic game species. invasive wild pigs (Sus scrofa) are known to depredate nests, and have been expanding throughout the distributed range of wild turkeys in north America. We sought to gain better insight on the magnitude of wild pigs depredating wild turkey nests. We constructed simulated wild turkey nests throughout the home ranges of 20 GPS-collared wild pigs to evaluate nest depredation relative to three periods within the nesting season (i.e., early, peak, and late) and two nest densities (moderate = 12.5-25 …

Effect Of Vaccination With A Novel Gnrh-Based Immunocontraceptive On Immune Responses And Fertility In Rats, Giovanna Massei, D. Cowan, Douglas C. Eckery, Richard E. Mauldin, M. Gomm, P. Rochaix, Fergal Hill, R. Pinkham, Laura A. Miller

United States Department of Agriculture Wildlife Services: Staff Publications

1. As human-wildlife conflicts increase worldwide, novel methods are required for mitigating these conflicts. Fertility control, based on immunocontraceptives, has emerged as an alternative option to lethal methods for managing wildlife.

2. Immunocontraceptives are vaccines that generate an immune response to key components of an animal's reproductive system. Some of these vaccines target the gonadotropin-releasing hormone (GnRH) and have been used successfully as contraceptives for many wildlife species. However, the need to capture animals for treatment limits the field applications of injectable vaccines. The availability of orally delivered immunocontraceptives would increase the breadth of applications of fertility control for wildlife …

Ecological Drivers Of African Swine Fever Virus Persistence In Wild Boar Populations: Insight For Control, Kim M. Pepin, Andrew J. Golnar, Zaid Abdo, Tomasz Podgórski

United States Department of Agriculture Wildlife Services: Staff Publications

Environmental sources of infection can play a primary role in shaping epidemiological dynamics; however, the relative impact of environmental transmission on host-pathogen systems is rarely estimated. We developed and fit a spatially explicit model of African swine fever virus (ASFV) in wild boar to estimate what proportion of carcassbased transmission is contributing to the low-level persistence of ASFV in Eastern European wild boar. Our model was developed based on ecological insight and data from field studies of ASFV and wild boar in Eastern Poland. We predicted that carcass- based transmission would play a substantial role in persistence, especially in low-density …

Influenza A Viruses In Peridomestic Mammals, J. Jeffrey Root, Susan A. Shriner

United States Department of Agriculture Wildlife Services: Staff Publications

During recent years, serological evidence has shown that a number of peridomestic mammals (e.g., those commonly found in or around human structures) are naturally exposed to influenza A viruses (IAVs). In addition, experimental studies have demonstrated that many of these species can successfully replicate several different IAVs, including IAVs of high consequence to public or agricultural health. The replication of some IAVs within this group of mammals could have implications for biosecurity associated with poultry production and live bird markets in some regions of the world. Given this evidence, the need for further study and understanding of the role that …

Invasive Rat Establishment And Changes In Small Mammal Populations On Caribbean Islands Following Two Hurricanes, Aaron B. Shiels, Claudia D. Lombard, Laura Shiels, Zandy Hillis-Starr

United States Department of Agriculture Wildlife Services: Staff Publications

Invasive mammals, particularly black rats (Rattus rattus), house mice (Mus musculus), and mongoose (Herpestes auropunctatus) are established on many tropical islands and threaten natural resources such as native birds, sea turtles, lizards, invertebrates, and plants. St. Croix (U.S. Virgin Islands, Caribbean) has a diversity of natural resources being protected from invasive mammals by U.S. conservation agencies. Sandy Point National Wildlife Refuge and Buck Island Reef National Monument receive among the highest density of nesting sea turtles in the region, including annual nesting populations of 50e250 leatherbacks (Dermochelys coriacea), 25e80 hawksbills (Eretmochelys imbricata), and 100e250 green turtles (Chelonia mydas). Buck Island …

Effects Of Wild Pig Disturbance On Forest Vegetation And Soils, Steven M. Gray, Gary J. Roloff, Daniel B. Kramer, Dwayne R. Etter, Kurt C. Vercauteren, Robert A. Montgomery

United States Department of Agriculture Wildlife Services: Staff Publications

In North America, wild pigs (Sus scrofa; feral pigs, feral swine, wild boars) are a widespread exotic species capable of creating large‐scale biotic and abiotic landscape perturbations. Quantification of wild pig environmental effects has been particularly problematic in northern climates, where they occur only recently as localized populations at low densities. Between 2016 and 2017, we assessed short‐term (within ~2 yrs of disturbance) effects of a low‐density wild pig population on forest features in the central Lower Peninsula of Michigan, USA. We identified 16 8‐ha sites using global positioning system locations from 7 radio‐collared wild pigs for sampling.Within each …

Placebo Oral Rabies Vaccine Bait Uptake By Small Indian Mongooses (Herpestes Auropunctatus) In Southwestern Puerto Rico, Are R. Berentsen, Richard B. Chipman, Kathleen M. Nelson, Kenneth S. Gruver, Frank Boyd, Steven F. Volker, Amy J. Davis, Ad Vos, Steffen Ortmann, Amy Gilbert

United States Department of Agriculture Wildlife Services: Staff Publications

The small Indian mongoose (Herpestes auropunctatus) is a rabies reservoir in areas of the Caribbean including Puerto Rico, but no rabies vaccination program targeting this host exists. We used two derivatives of iophenoxic acid (IPA) to evaluate placebo oral rabies vaccine bait uptake by mongooses in southwestern Puerto Rico. We hand-distributed baits at an application rate of 200 baits/km² at three, 400 ha, sites during autumn 2016 and spring 2017. Each site contained 90–100 cage traps in a 100 ha central trapping area. We used ethyl-IPA as a biological marker during the autumn and methyl-IPA during the …

Bird-Livestock Interactions Associated With Increased Cattle Fecal Shedding Of Ciprofloxacin-Resistant Escherichia Coli Within Feedlots In The United States, James C. Carlson, Jeffrey C. Chandler, Bledar Bisha, Jeffrey T. Lejeune, Thomas E. Wittum

United States Department of Agriculture Wildlife Services: Staff Publications

This research study was conducted to determine if bird depredation in feedlots is associated with the prevalence of ciprofloxacin-resistant Escherichia coli in cattle and to determine if removal of invasive bird species could be an effective management strategy to help reduce ciprofloxacin-resistant E. coliin cattle within the United States. european starlings (Sturnus vulgaris) were collected from feedlots within multiple geographic regions within the United States and european starlings within all regions tested positive for ciprofloxacin-resistant E. coli, but prevalence differed by region. Total number of birds on feedlots were positively associated with increased cattle fecal shedding of ciprofloxacin-resistant E. coli. …