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Veterinary Medicine Research & Publications

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Open Access
Salamander braincase morphology as revealed by micro‐computed tomography
(Wiley, 2022-01-25) Szostakiwskyj, Matt; Anderson, Jason Scott
Morphological data sets are misleading in salamander (Caudata) phylogeny due to the relative homoplasy of the dermal skull observed in paedomorphic forms, leading to the trend of excluding morphology when exploring questions of salamander phylogeny. Investigations in caecilians (Gymnophiona) have demonstrated that the inclusion of braincase morphology can rescue morphological phylogenetic analyses and produce topologies congruent with molecular data sets. We scanned 28 species (25 genera) of salamander, representing all 10 families, with high-resolution micro-computed tomography to investigate braincase variation. We describe the morphology of the braincase for all 10 families and distinguish between paedomorphic and metamorphic morphologies. Our results demonstrate a general uniformity amongst metamorphic species with variation largely restricted to the occipito-otic region. A greater range of variation is observed within paedomorphic forms than would be expected when considering the homoplasy of the dermal skull. Obligate paedomorphic forms demonstrate considerably more variation in the anterior braincase than do facultative paedomorphs, which we suggest is evidence of a greater complexity in the evolution and development of these forms than neoteny alone would produce. This raises the question of character independence within morphological data sets and warrants further investigation into the correlation of other characters before morphological data are omitted.
Open Access
Amendment: Exploring Antimicrobial Resistance in Escherichia coli: A Scoping Review Protocol Comparing Antibiotic-free and Conventionally Raised Beef Cattle in Canada and the United States of America
(Veterinary Medicine, Libraries and Cultural Resources, 2024-03-14) Sanguinetti, Veronica Maria; Davies, Willow-Bethany; Ganshorn, Heather; Checkley, Sylvia Lee
Open Access
Exploring Antimicrobial Resistance in Escherichia coli: A Scoping Review Protocol Comparing Antibiotic-free and Conventionally Raised Beef Cattle in North America
(2023-07-10) Sanguinetti, Verónica María; Davies, Willow-Bethany O.; Ganshorn, Heather; Checkley, Sylvia L.
Escherichia coli is a gram-negative bacterium commonly found in the human and animal gastrointestinal tract. Beef cattle are considered reservoirs, although some strains can trigger diarrhea in newborn calves. Certain strains, such as Shiga toxin-producing E. coli (STECs), pose health risks in humans and animals [2]. Antibiotic resistance in E. coli is a significant concern in human and veterinary medicine, as it can lead to treatment challenges and transmission to other bacteria [3]. Canada and the United States Drug-Resistant Index score lie among the lowest ten countries, and this can be associated with the wide use of narrow-spectrum penicillin [4]. Strains encode accessory resistance and are likely resistant to multiple antibiotic classes [5]. Evidence suggests that E. coli can be resistant to more than one antimicrobial drug, and the most common resistance phenotypes are older drugs such as tetracycline, sulfonamide, streptomycin, and ampicillin [6]. Antibiotic-free beef cattle certifications have been implemented to address antimicrobial resistance concerns in the food chain [7]. However, the evidence regarding the prevalence of resistant bacteria in antibiotic-free production systems is limited. Antimicrobial resistance in Escherichia coli represents a significant One Health issue, highlighting the urgent need to explore alternatives, such as limiting the use of antibiotics in beef cattle production to therapeutic treatments, to mitigate the spread of resistant strains and safeguard human and animal health [8]. Objectives The objective of this study is to lead a scoping review to define the range of existing research in the area, individualize research gaps and suggest areas important for future research studies about Antimicrobial Resistance in Escherichia coli of Antibiotic-free and Conventionally Raised Beef Cattle from North America. Methods This scoping review has been designed following the JBI Reviewer’s Manual [9] and the PRISMA ScR guidelines for scoping reviews [1] to report it and the search question was constructed using the PICO framework. We will search the literature for peer-reviewed articles using the following databases: CAB Abstracts, BIOSIS Previews, Environmental Complete, the Web of Science’s Science Citation Index and Emerging Sources Citation Index. The grey literature search will include a search of ProQuest Dissertations and the websites of relevant government departments, agencies, and industry groups. Two independent reviewers will screen the articles at the title, abstract, and full-text levels.
Open Access
Exploring Antimicrobial Resistance in Escherichia coli: A Scoping Review Protocol Comparing Antibiotic-free and Conventionally Raised Beef Cattle in North America
(Veterinary Medicine, Libraries and Cultural Resources, University of Calgary, 2023-06-20) Sanguinetti, Veronica Maria; Davies, Willow-Bethany O.; Ganshorn, Heather; Checkley, Sylvia L.
Escherichia coli is a gram-negative bacterium commonly found in the human and animal gastrointestinal tract. Antibiotic resistance in E. coli is a significant concern in human and veterinary medicine, as it can lead to treatment challenges and transmission to other bacteria [3]. Antibiotic-free beef cattle certifications have been implemented to address antimicrobial resistance concerns in the food chain [7]. Objectives: To define the range of existing research in the area, individualize research gaps and suggest areas important for future research studies about Antimicrobial Resistance in Escherichia coli of Antibiotic-free and Conventionally Raised Beef Cattle from North America. Methods: This scoping review has been designed following the JBI Reviewer’s Manual and the PRISMA ScR guidelines for scoping reviews. The search question was constructed using the PICO framework. We will search the literature for peer-reviewed articles using the following databases: CAB Abstracts, BIOSIS Previews, Environmental Complete, the Web of Science’s Science Citation Index and Emerging Sources Citation Index. The grey literature search will include a search of ProQuest Dissertations and the websites of relevant government departments, agencies, and industry groups. Two independent reviewers will screen the articles at the title, abstract, and full-text levels.
Open Access
Rotational grazing in beef cattle pasture-based systems as a soil health practice to support climate change mitigation and biodiversity: protocol for a systematic review
(2023-06-26) Sanguinetti, Lucia Ines; Tang, Minfeng; Ganshorn, Heather; Lhermie, Guillaume
Background: The rise in population and industrial practices are causing negative impacts on our environment, leading to climate change. This phenomenon triggers extreme weather events, increasing soil evaporation and lowering water availability for plants. It requires the attention of every economic sector, and agriculture has the potential to mitigate its effects. The Canadian government has recently launched the Sustainable Agriculture Strategy plan, which goal is to encourage the use of eco-friendly practices and the implementation of new technologies. One of the strategies promoted is rotational grazing, for supporting soil health. Rotational grazing is a practice that involves residency and rest periods of pastures for grazing cattle. This study aims to conduct a systematic review to identify the current rotational grazing systems used worldwide and their impact on GHG emissions, biodiversity, soil health, and productivity. Our findings will inform the value of rotational grazing in beef systems in Canada. Evaluating the cost/benefit relationship of implementing recommended rotational grazing systems with different levels of intensification. Focusing on semi-arid and continental climates, considering both tame and native grassland that pre-exist in Canada. Methods: This systematic review will include all types of rotational grazing studies under beef grazing operations. As well as: articles that estimate GHG emissions (IPCC methodology), native and tame pastures (Poaceae and Fabaceae) with any type of intensification, the climate of interest (continental, semi-arid), relevant plant species to Canada, biodiversity and Bos Taurus cattle population. If possible, articles will be included in a meta-analysis examining the impacts of the different rotational practices.
Open Access
Identifying research gaps regarding the influence of maternal stress on bovine female offspring’s Anti-Müllerian hormone (AMH) concentrations: A scoping review protocol
(2023-06-06) Birkenhagen, Brian; Ganshorn, Heather; Hernandez-Medrano, Juan
Introduction: Farmers consistently aim to increase cattle longevity in their herds to improve sustainability of cattle production. However, infertility or low fertility is one of the reasons for culling healthy dairy and beef cows with a negative impact on longevity. In dairy cattle, around 14.2% in Canada and 26.7% in the U.S. (CDIC, 2022; USDA, 1996) of cattle are culled due to fertility issues, with a similar percentage for beef cattle (US, 27.2%; USDA, 1999). Fertility in these animals shows a progressive decline which points to a long-term effect that could start during ovarian development (Wathes et al., 2014 ). The ovaries in cattle develop in utero (30-90 d of pregnancy) with heifers having their lifetime supply of follicles at birth (i.e., ovarian reserve, OR; Hernandez-Medrano et al., 2012). Any disruption in the development of the OR may result in fertility complications and decreased reproductive longevity (Hernandez-Medrano et al., 2012; Mossa et al., 2015; Akbarinejad et al., 2017). Maternal stress, such as thermal or nutritional, are some of those disruptions that have a long-lasting effect on offspring health and productive potential. The exact mechanisms for these effects are still elusive. Growing follicles produce the dimeric glycoprotein hormone, Anti-Müllerian hormone (AMH), which has been reported as a marker for the antral follicular population in cows and their reproductive potential (Alward & Bohlen, 2019). This review will identify publications that have studied the link between maternal stress and gonadal development, ultimately resulting in a breakdown of what’s known regarding the influence of maternal stress during gestation on AMH concentrations in female offspring. Objective: The objective of this review is to identify the published literature discussing how AMH concentrations in bovine female offspring are influenced by nutritional or thermal stress experienced by the dam during gestation. The results will highlight areas of consensus and propose research approaches to fill the gaps in knowledge. The overall goal of this scoping review is to evaluate the feasibility to implement AMH as an early marker of reproductive potential and help producers improve the sustainability of their farms. Methods: A scoping review reported according to the PRISMA scoping review extension will be carried out with a total of five databases being used for the study (CAB Abstracts, MEDLINE, BIOSIS Previews, the Web of Science, and SciELO). Concepts to be considered in the primary search include cattle, pregnancy, nutritional or thermal stress, and offspring outcomes. Article screening will consist of two stages: title and abstract, and full text. Articles will be included in the review if they discuss AMH concentrations, bovine female offspring, and are peer-reviewed academic journal articles or conference proceedings. Articles will then be excluded from the study if they are non-English or non-Spanish. The articles that meet this criterion will then be charted in an Excel spreadsheet.
Open Access
A multimethod approach to the differentiation of enthesis bone microstructure based on soft tissue type
(Wiley, 2021-06) Whitebone, S Amber; Bari, A S M Hossain; Gavrilova, Marina L; Anderson, Jason S
Whereas there is a wealth of research studying the nature of various soft tissues that attach to bone, comparatively little research focuses on the bone's microscopic properties in the area where these tissues attach. Using scanning electron microscopy to generate a dataset of 1600 images of soft tissue attachment sites, an image classification program with novel convolutional neural network architecture can categorize images of attachment areas by soft tissue type based on observed patterns in microstructure morphology. Using stained histological thin section and liquid crystal cross-polarized microscopy, it is determined that soft tissue type can be quantitatively determined from the microstructure. The primary diagnostic characters are the orientation of collagen fibers and heterogeneity of collagen density throughout the attachment area thickness. These determinations are made across broad taxonomic sampling and multiple skeletal elements.
Open Access
Scoping Review of kinetic based methods for objective gait analysis in horses
(2022-07-29) Devolin, Alanna; Murari, Kartikeya; Ganshorn, Heather; Scott, W. Michael
Background: Gait analysis for horses can be performed either subjectively or objectively. The subjective method observes horses in motion. Whereas for an objective analysis, data on specific gait parameters are collected and reviewed. Objective gait analysis can be broken down into two disciplines: kinetic and kinematic based. Kinetic methods rely on applied force(s) data and kinematic methods analyze temporal and spatial parameters of gait. Objective: To complete a scoping review of kinetic based methods used for objective gait analysis Eligibility Criteria: Any articles (peer reviewed) and conference papers (peer reviewed and published) will be included in this study. Articles must include a kinetic based means of gait analysis that has been applied to horses. Kinematic based methods of analysis and any articles with humans or other animals will be excluded. Sources of evidence: Searches will be conducted in MEDLINE, CAB Abstracts, SportDiscus, Compendex, and IEEE Xplore.
Open Access
Consistency in Applying the Loss of Righting Reflex to Assess Unconsciousness during Induction of General Anesthesia in Rats and Mice: A Systematic Review Protocol
(2022-06-29) Merenick, Dexter; Jessel, Anisha; Ganshorn, Heather; Pang, Daniel
This systematic review protocol will evaluate the following question: How is the loss of righting reflex performed across studies to assess unconsciousness during induction of general anesthesia in rats and mice? The overall aim of this paper is to critically assess and evaluate the current published knowledge surrounding the LORR methodology and how it is performed.
Open Access
The Use of Telepathology in Veterinary Medicine: A Scoping Review Protocol
(2021-11-26) Rogers, Lindsay; Ganshorn, Heather; Galezowski, Angelica; Goldsmith, Dayna; Legge, Carolyn; Davies, Jennifer
Background: Telepathology, as a subset of teleconsulting, is pathological interpretation performed at a distance. Diagnostics can be difficult to access by rural veterinary practices yet are vital to the health of production animal herds often serviced by these practices. The technology and availability of telepathology services has not been assessed to identify gaps in the literature and means of improving diagnostics services to rural veterinary clinics. Objectives: The objective of this scoping review is to provide an overview of how telepathology is being used in veterinary medicine. Eligibility criteria: Peer reviewed journal articles and grey literature in the English language and published after 2000 will be included in the study. It must be relevant to performing pathological interpretation at a distance in veterinary medicine. Literature about radiology, bacteriology, and relevant to human medicine will be excluded. Sources of evidence: Searches will be conducted in CAB Abstracts and MEDLINE. Websites from national veterinary medical associations, veterinary pathologist membership organizations, and international animal health organizations will be searched for grey literature. Charting methods: Data charting will include study characteristics, sector of pathology, technology used for communication, technology used for pathological interpretation, and a summary of the literature objectives and conclusions.
Open Access
The anatomy of the dermatocranium and mandible of Cacops aspidephorus Williston, 1910 (Temnospondyli: Dissorophidae), from the Lower Permian of Texas
(Taylor and Francis, 2020-01) Anderson, Jason S.; Scott, Diane; Reisz, Robert R.
For the first time, the cranial suture pattern for the type species of Cacops, C. aspidephorus, is described in detail. A majority of sutures, including the lower jaw, the skull roof, and the palate, are now known in detail, although details are still lacking for the posterior skull table. Notable new information about C. aspidephorus includes the presence of a lateral exposure of the palatine (LEP), a lateral exposure of the ectopterygoid (LEE) that fuses with the jugal with growth, and a subtympanic flange composed mostly of the supratemporal. Cacops aspidephorus is very similar to C. morrisi, but differences, including a fully closed otic notch in C. aspidephorus, are sufficient to maintain both as distinct species. Uniquely, C. aspidephorus shows palatal dentition of the same size as the marginal dentition, but it remains to be seen whether this is a widespread feature or ontogenetically transient. These new data will finally permit the inclusion of this iconic taxon, described over 100 years ago, into larger-scale phylogenies of dissorophoid and temnospondyl relationships.
Open Access
Protocol for the systematic review of strategies used in beef cattle to prevent or control internal or external parasites
(2021-08) Agbese, Samuel; Sanguinetti, V. Margarita; Gilleard, John; Ganshorn, Heather; Windeyer, M. Claire
This paper describes the protocol for a systematic review that will evaluate the following question: What strategies are most effective for the prevention or control of internal or external parasites in beef cattle herds? The overall objective of this systematic review is to critically assess and synthesize the current published knowledge on the aforementioned review question.
Open Access
Protocol for 'Tick Surveillance Systems in North America: A Scoping Review'
(2021-07) Romney, Elise; Cork, Susan; Envik, Akaysha; Ganshorn, Heather; Couloigner, Isabelle; Checkley, Sylvia
Introduction: Tick surveillance is important to detect new ticks or changes in tick occurrence and distribution within a region. This facilitates communication of and response to changes in tick distribution. Tick surveillance systems also provide a framework from which to assess tick-borne disease carriage. This information can be used to launch further investigation and inform risk assessments and mitigation strategies for tick-borne disease in people and animals. For example, many tick surveillance systems focus on blacklegged ticks, like Ixodes scapularis, that can carry Borrelia burgdorferi, the causative agent of Lyme disease. Lyme disease can cause clinical signs such as erythema migrans, meningitis, cranial neuropathy, arthritis, carditis (1 ) in people and some animal species like dogs and horses. White-footed mice and other small mammals are important natural reservoirs of the bacteria while deer and other mammals can carry the ticks (2,3). Hard ticks (Family: Ixodidae) are found in an increasingly broad range of environments as climate change apparently makes it possible for them to survive in regions where they had not previously been found (4). Lyme disease, and other tick-borne diseases such as Rocky Mountain spotted fever and Anaplasmosis, are a One Health problem, at the interface between human health, animal health, and the environment. Objectives: The primary objective of this scoping review is to describe the characteristics of tick surveillance systems from 1960 onward. This research will focus on reviewing published and grey literature and then describing the characteristics of tick surveillance systems, including location, year, type of surveillance, and method of data collection. Methods: This scoping review will be carried out following PRISMA guidelines for scoping reviews. Databases used include MEDLINE, CAB Abstracts, BIOSIS Previews and the Web of Science Core Collection. ProQuest Dissertations will be searched for relevant dissertations. The articles will be screened at the title and abstract, and full text levels by two reviewers blinded to each other's assessment. Articles published prior to 1960 will be excluded, and only articles that describe surveillance systems will be included. Government websites will also be searched for information about tick surveillance programs, globally.
Open Access
Factors Associated with Antimicrobial Resistant Enterococci in North American Beef Cattle: A Scoping Review Protocol
(2021-07-05) Strong, Kayla; Marasco, Kaitlin; Invik, Jesse; Ganshorn, Heather; Reid-Smith, Richard; Waldner, Cheryl; Otto, Simon; Chapman, Brennan; Checkley, Sylvia
Introduction: Enterococcus spp. is a commensal gram-positive bacterium routinely found in humans and bovines' intestinal tracts; however, it can lead to infection when found outside the intestinal tract.1 There is increasing difficulty in treating Enterococcal infections due to a rise in resistance, particularly multidrug resistance.2 The rise of antimicrobial resistance is a One Health problem resulting from antimicrobial use in human health, animal health, and the environment.3 This research focuses on the connection between animal and human health, and considers the epidemiology of antimicrobial resistance within the North American beef cattle production system. The research will identify factors associated with antimicrobial resistance in Enterococcus spp. from cow-calf operations up to but not including human beef consumption. This project is a component of the broader iAM.AMR initiative. Objectives: The primary objective is to identify what factors increase or decrease the prevalence of antimicrobial resistance in Enterococcus spp. within the North American Beef Cattle Industry, from cow-calf operations to the retail setting. The results will populate a component of an integrated assessment model as a component of the Integrated Assessment Model on Antimicrobial Resistance (iAM.AMR) project, built using Analytica software (Educational Professional license, Lumina) Methods: A double-blinded scoping review following PRISMA guidelines will examine five databases (MEDLINE, BIOSIS Previews, the Web of Science Science Citation Index and Emerging Sources Citation Index, Embase, and CAB Abstracts). The search will consider Enterococcus spp., Antimicrobials, Resistance, beef cattle, and search term variants. Articles identified will be screened at three primary stages: bibliography, title and abstract, and full text. The authors will exclude articles published before 1984 (Enterococcus spp. was designated a species in 1984), journals specific to a livestock species that is not beef cattle, and non-English articles. Articles that are solely In vitro, specific to fermented meat, opinion-based, or not applicable to the North American context will also be excluded. Articles will be included if there is an intervention identified and the AMR impact of the intervention measured. Article information will be charted in an excel spreadsheet. Following the charting process, authors will identify articles to be included in the iAM.AMR Collection of Epidemiologically Derived Associations with Resistance (CEDARS) database. These articles must have an extractable "factor" associated with AMR Enterococcus spp, presented as an odds ratio or prevalence comparison (in text or graph) specific to an "intervention" and "control." The study must use non-selective media and have the total (N) provided for the intervention and control. Relevant data will be collected and coded into an Access (V2103, Microsoft) database. Meta-analysis will occur if two articles examine the same factor and are comparable in the research design and study population.
Open Access
Identifying Research Gaps for the Role of the Environment in Transmission of Antimicrobial-Resistant Escherichia coli in Cow-Calf Operations in North America: A Scoping Review Protocol
(2021-06-30) Mangat, Priyanka; Le, Stephanie; Ganshorn, Heather; Checkley, Sylvia; Liljebjelke, Karen
Escherichia coli (E.coli) is a gram negative rod-shaped bacteria which is found in the intestines of people, animals and in the environment. E.coli is also found in food and untreated water. Antimicrobial use in animal production against bacteria such as E. coli is essential for maintaining animal health. However, increased antimicrobial use poses the risk of contributing to the problem of antimicrobial resistance. Antimicrobial resistance occurs when microorganisms selectively develop mechanisms to protect themselves from the effects of antimicrobial compounds. Antimicrobial resistance is a One Health concern as it impacts animal, human and ecosystem health. In North America, the term cow-calf production refers to cattle raised exclusively or largely on pasture, having a grass- or hay-based diet, and which may consume a low amount of concentrate diet, producing an annual crop of calves. The calves are intended for beef production and are usually backgrounded on pasture or backgrounding lots and then finished with a high concentrate diet in feedlots. Although this literature review is not restricted to North America, information retrieved will be discussed in relation to cow-calf operations in North America. For the purpose of this scoping review, the term “environment” will refer to environmental features such as: manure, wildlife, soil, insects, and water sources. By including these search terms, the scoping review will identify environmental reservoirs that have been shown to impact the transmission of antimicrobial-resistant E. coli in cow-calf operations. Our aim is to conduct a scoping review of the evidence regarding the role of the environment in the transmission and maintenance of antimicrobial-resistant E. coli within cow-calf operations. This study will identify gaps in knowledge regarding the reservoirs and transmission of antimicrobial-resistant E. coli in cow-calf operations (2). Because the mechanisms of maintenance and transmission of antimicrobial resistance in the environment are obscure, this scoping review will aid in determining the quantity and nature of information that presently exists in this field, and aid in identifying directions for future research (3). The review will be conducted between July 1, 2021 and August 31, 2021.
Open Access
Protocol for a systematic review of disease control strategies used to prevent infectious mortality and morbidity in pre-weaned beef calves
(2021-05-07) Windeyer, M. Claire; Sanguinetti, V. Margarita; Agbese, Samuel; Ganshorn, Heather
It is essential to optimize the production of calves in order to maximize economic returns to producers and the availability of feeder cattle and replacement stock for the industry. Morbidity and mortality in beef calves have negative impacts on beef operations and are associated with considerable economic damage (2,3). By implementing effective disease control strategies, morbidity and mortality caused by Bovine Respiratory Disease (BRD) and Neonatal Calf Diarrhea (NCD) may be reduced. Studies have shown that failed transfer of passive immunity (3–7), season of birth (8), herd size (2,3), assistance at calving (3,9), and purchasing adult cattle and using community pastures (10) are risk factors for morbidity and mortality in calves. Disease control strategies are an essential component of the health management of beef herds (11) and some preventive practices have shown financial benefits (12). Herd demographics and management practices alter the epidemiology of disease within the herd (13), with various strategies aiming to improve the animal environment, boost the immune system (14), and diminish animal exposure to potential pathogens (15). Risk factors associated with the multifactorial syndromes of BRD and NCD have been explored mainly in dairy calves (5–8), but there are a limited number of studies related to beef calves (16) and no efforts to summarize the available literature have been reported. A systematic review of the current scientific literature will be conducted focusing on colostrum management, vaccination strategies, biosecurity, biocontainment, metaphylactic use of antibiotics, and other strategies used to prevent mortality and morbidity caused by BRD and NCD in pre-weaned beef calves. To the best of our knowledge, there is no published systematic review on disease control strategies used in beef calves during the preweaning stage.
Open Access
Variations in the profitability of dairy farms in Victoria, Australia by different levels of engagement in bovine Johne’s disease control
(2020-11-13) Burden, Paul; Hall, David C.
Paratuberculosis or Johne’s disease (JD) prevalence in Australia is low at the cow-level with varying herd-level prevalence. Control strategies incorporating vaccination are limited, suggesting opportunities for changes in regulatory oversight. In order to study this further, we examined the economic benefits of participation in JD control programmes in Australia with and without vaccination as well as knowledge, attitudes, and practices (KAP) relating to JD. We used an online questionnaire to gather information describing demographics and KAP from 71 Australian dairy farms. Data from fully completed questionnaires from 32 farms in Victoria, Australia combined with cost and revenue data averaged from several years of the Dairy Farm Monitor Project were used to then simulate a larger robust dataset. These production data informed the simulation model to establish farm profitability. A partial farm budget was then developed to estimate the benefits of engaging in JD control activities. Respondents who stated they participated in JD control programmes gained an additional $43.80/cow/year net income (profit) compared to non-participants. Respondents also using a JD vaccine gained an additional $35.84/cow/year over non-users; this represents $10.56/cow/year over and above the average producer in the industry. However, we also noted that there clearly exists a barrier between farmers stated intentions to participate and actual participation in JD control activities. These significant differences in net income realized by farms using different approaches to JD control (in this case, adoption of vaccination) offer a starting point from which to explore questions of how much farmers would be willing to pay for control activities, why they are willing to pay, and the likelihood of participating. Communication of the benefits of participation needs to improve to bridge this gap between farmers stated intentions and their actions. Simulation modelling suggests increased profitability from participation in JD control programs and vaccination in Australia. The JD regulatory policies of other countries may benefit from the Australian experience with JD control.
Open Access
Prevalence and Genetic Basis of Antimicrobial Resistance in Non-aureusStaphylococci Isolated from Canadian Dairy Herds
(Frontiers in Microbiology, 2018-01) Nobrega, Diego B; Naushad, Sohail; Naqvi, S Ali; Condas, Larissa A Z; Saini, Vineet; Kastelic, John P; Luby, Christopher; De Buck, Jeroen; Barkema, Herman W
Emergence and spread of antimicrobial resistance is a major concern for the dairy industry worldwide. Objectives were to determine: (1) phenotypic and genotypic prevalence of drug-specific resistance for 25 species of non-aureus staphylococci, and (2) associations between presence of resistance determinants and antimicrobial resistance. Broth micro-dilution was used to determine resistance profiles for 1,702 isolates from 89 dairy herds. Additionally, 405 isolates were sequenced to screen for resistance determinants. Antimicrobial resistance was clearly species-dependent. Resistance to quinupristin/dalfopristin was common inStaphylococcus gallinarum(prevalence of 98%), whereasS. cohniiandS. arlettaewere frequently resistant to erythromycin (prevalence of 63 and 100%, respectively). Prevalence of resistance was 10% against β-lactams and tetracyclines. In contrast, resistance to antimicrobials critically important for human medicine, namely vancomycin, fluoroquinolones, linezolid and daptomycin, was uncommon (< 1%). Genes encoding multidrug-resistance efflux pumps and resistance-associated residues in deducted amino acid sequences of thefolPgene were the most frequent mechanisms of resistance, regardless of species. The estimated prevalence of themecAgene was 17% forS. epidermidis. Several genes, includingblaZ, mecA, fexA, erm, mphC, msrA, andtetwere associated with drug-specific resistance, whereas other elements were not. There were specific residues ingyrBfor all isolates of species intrinsically resistant to novobiocin. This study provided consensus protein sequences of key elements previously associated with resistance for 25 species of non-aureusstaphylococci from dairy cattle. These results will be important for evaluating effects of interventions in antimicrobial use in Canadian dairy herds.
Open Access
Refinement of intraperitoneal injection of sodium pentobarbital for euthanasia in laboratory rats (Rattus norvegicus)
(BioMed Central, 2017-02-21) Zatroch, Katie K; Knight, Cameron G; Reimer, Julie N; Pang, Daniel S J
BACKGROUND: The Canadian Council on Animal Care and American Veterinary Medical Association classify intraperitoneal (IP) pentobarbital as an acceptable euthanasia method in rats. However, national guidelines do not exist for a recommended dose or volume and IP euthanasia has been described as unreliable, with misinjections leading to variable success in ensuring a timely death. The aims of this study were to assess and improve efficacy and consistency of IP euthanasia. In a randomized, blinded study, 51 adult female Sprague-Dawley rats (170-495 g) received one of four treatments: low-dose low-volume (LL) IP pentobarbital (n = 13, 200 mg/kg pentobarbital), low-dose high-volume (LH) IP pentobarbital (n = 14, 200 mg/kg diluted 1:3 with phosphate buffered saline), high-dose high-volume (HH, n = 14, 800 mg/kg pentobarbital), or saline. Times to loss of righting reflex (LORR) and cessation of heartbeat (CHB) were recorded. To identify misinjections, necropsy examinations were performed on all rats. Video recordings of LL and HH groups were analyzed for pain-associated behaviors. Between-group comparisons were performed with 1-way ANOVA and Games-Howell post hoc tests. Variability in CHB was assessed by calculating the coefficient of variation (CV). RESULTS: The fastest euthanasia method (CHB) was HH (283.7 ± 38.0 s), compared with LL (485.8 ± 140.7 s, p = 0.002) and LH (347.7 ± 72.0 s, p = 0.039). Values for CV were: HH, 13.4%; LH, 20.7%; LL, 29.0%. LORR time was longest in LL (139.5 ± 29.6 s), compared with HH (111.6 ± 19.7 s, p = 0.046) and LH (104.2 ± 19.3 s, p = 0.01). Misinjections occurred in 17.0% (7/41) of euthanasia attempts. Pain-associated behavior incidence ranged from 36% (4/11, LL) to 46% (5/11, HH). CONCLUSIONS: These data illustrate refinement of the IP pentobarbital euthanasia technique. Both dose and volume contribute to speed of death, with a dose of 800 mg/kg (HH) being the most effective method. An increase in volume alone does not significantly reduce variability. The proportion of misinjections was similar to that of previous studies.
Open Access
Student Attainment of Proficiency in a Clinical Skill: The Assessment of Individual Learning Curves
(Public Library of Science, 2014-02-20) Campbell, Robert D.; Hecker, Kent G.; Biau, David J.; Pang, Daniel S. J.