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The irreproducibility in scientific research has become a critical issue. Despite the essential role of rigorous methodology in constructing a scientific article, more than half of publications, on average, are considered non-reproducible. The implications of this irreproducibility extend to reliability problems, hindering progress in technological production and resulting in substantial financial losses. In the context of laboratory animal research, this work emphasizes the importance of choosing an appropriate experimental model within the 3R's principle (Refine, Reduce, Replace). This study specifically addresses a deficiency in data specification in scientific articles, revealing inadequacies in the description of crucial details, such as environmental conditions, diet, and experimental procedures. For this purpose, 124 articles from journals with relevant impact factors were analyzed, conducting a survey of data considered important for the reproducibility of studies. Important flaws in the presentation of data were identified in most of the articles evaluated. The results of this study highlight the need to improve the description of essential information, standardizing studies, and ensuring the reproducibility of experiments in areas such as metabolism, immunity, hormones, stress, among others, to enhance the reliability and reproduction of experimental results, aligning with international guidelines such as ARRIVE and PREPARE.

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Tail docking is a husbandry practice widely incorporated in sheep farms around the world. It is an irreversible mutilation that impairs animal welfare, both immediately and in the longer term. The defence of tail docking as a practice is centred around the perception that doing so contributes to the promotion of local hygiene, allowing the use of the wool, facilitating reproductive management and reducing the chances of myiasis, a disease caused by the invasion of blowfly larvae in the tissues of warm-blooded animals. However, current understanding of farm animal welfare questions the need to maintain practices such as tail docking. Thus, the aim of this study was to evaluate the effect of tail docking on the incidence of Cochliomyia hominivorax myiasis in sheep in an experimental flock in Brazil during a six-year retrospective cohort study. Relative risk, odds ratio and incidence rate ratio were the association measures adopted. A total of 4,318 data-points were collected and supplied the analytical model. Tail docking did not decrease the risk and, on the contrary, was found to increase the chances of sheep being affected by myiasis. The results support the hypothesis that tail docking is not a protective factor against the occurrence of myiasis and further fuel calls for a rethink of tail docking being deployed as a blanket measure in the prevention of myiasis in sheep.

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Background and Aim: Treatment of endometriosis involves pain relief which is achieved through the administration of analgesics and non-steroidal anti-inflammatory drugs, with or without the addition of hormone therapy. At present, studies investigating endometriosis pain management using experimental rat models and the use of medications are scarce. Therefore, this study aimed to systematically evaluate research trends and critical points in the field of endometriosis pain management using experimental models. Materials and Methods: A total of 30 publications related to this topic that were published from 2012 to 2022 were retrieved from various databases, including Web of Science, Scopus, PubMed, Embase, and CINAHL, using appropriate English keywords. The quality of the publications was evaluated using impact metrics, productivity, term density mapping, and author network. Results: The average publication rate was three articles per year, reaching its peak in 2021 at five articles per year. The United States and China were found to be the most productive countries, with 12 and 10 publications per year, respectively. The field of medicine (37.0%) was the most abundant, although the H-index was relatively low (13:13). Term density mapping involved the search of 542 keywords, of which 35 were selected, with only 8 exhibiting significant density. Conclusion: In the past decade, there has been a shortage of publications that have addressed pain in endometriosis in experimental models and, within this context the majority of the production and publication in this field has been performed by the United States and China. After performing this bibliometric review, it can be inferred that more research is required in this field, to develop new approaches and treatments for endometriotic pain.

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Danio rerio (zebrafish), originating from the Asian shallow waters, is a high-rise experimental model in the scientific community for its reproductive advantage and speed; with its completely sequenced genome and great genetic similarity with humans, in addition to the care and management facilitated indoors, make zebrafish an extremely viable option for scientific research. This literature review seeks to expose and clarify the means and main parameters for the establishment of a zebrafish production, maintenance or use facility, as well as the normative resolutions and legal requirements governing the establishment of these facilities; we also meet the installation conditions necessary for the construction and implementation of the installation, its parameters for maintenance, breeding, reproduction and management of zebrafish in the animal installation.

Danio rerio (zebrafish), oriundo das águas rasas asiáticas, é um modelo experimental em grande ascensão na comunidade científica por sua vantagem e velocidade reprodutivas; com seu genoma completamente sequenciado e grande similaridade genética com o ser humano, além do cuidado e manejo facilitado em ambientes fechados, tornam o zebrafish uma opção extremamente viável para a pesquisa científica. Esta revisão bibliográfica busca expor e esclarecer os meios e principais parâmetros para o estabelecimento de uma instalação de produção, manutenção ou utilização de zebrafish, bem como as resoluções normativas e requerimentos legais que regem o estabelecimento destas instalações; também reunimos as condições de instalação necessárias para a construção e implantação da instalação, seus parâmetros para a manutenção, criação, reprodução e manejo dos peixes-zebra na instalação animal.

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Considering the valuable environmental and cultural heritage existing in the world in the context of agribusiness, it is possible to highlight the role of ethno-zootechnics as an important new tool for understanding these values, the rescue and generational transmission of livestock knowledge are relevant. Given this, the objective was to understand the perception of milk producers from the Ethno-zootechnical perspective. Through a semi-structured script, questionnaires were carried out with 41 interviewees and representatives of dairy farms to registerthe relevance of basic cultural knowledge associating them with social, economic and social environmental development. Cluster analysis was carried out using the hierarchical method. It was concluded that part of the dairy farmers located in the Northwestregion of Minas Gerais state, the man/animal relationship is important, with traits of affection and utility. The transmission of traditional knowledge of the dairy activity is important, and that they believe that scientific and traditional knowledge canbe beneficial in rural activity.(AU)

Considerando o valioso patrimônio ambiental e cultural existente no mundo no contexto do agronegócio, é possível destacar o papel da etnozootecnia como uma nova ferramenta importante para a compreensão desses valores, o resgate e a transmissão geracional do conhecimento pecuário são relevantes. Diante disso, objetivou-se compreender a percepção dos produtores de leite na perspectiva Etnozootécnica. Foram aplicados questionários, por meio de um roteiro semiestruturado, com 41 entrevistados, representantes de fazendas leiteiras para registrar a relevância dos conhecimentos culturais básicos associando-os ao desenvolvimento social, econômico e socioambiental. A partir dos dados coletados procedeu-se com análise de cluster foi realizada pelo método hierárquico. Concluiu-se que para parte dos produtores de leite localizados na região Noroeste de Minas, a relação homem/animal é importante, com traços de afeto e utilidade. A transmissão do conhecimento tradicional da atividade leiteira é importante, e que eles acreditam que o conhecimento científico e tradicional pode ser benéfico na atividade rural.(AU)

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Lab animals, such as Guinea pigs (Cavia porcellus), are crucial for scientific development, as they play an important role in the development and quality control chain of vaccines and drugs distributed by the Brazilian public health system. Investigating their biological and physiological parameters is fundamental to raise and keep these animals, so the handling of the facilities that hold them can be updated whenever new information comes up, with the well-being of the animals and alignment with the 3 Rs in mind. In the search for understanding reproductive aspects of Guinea pigs, the present study had the main goal of studying puberty by means of estrous cycle analysis in short-haired Guinea pigs. Guinea pigs have a vaginal occlusive membrane that covers the vaginal orifice. Its rupture takes place gradually and naturally, moments before labor and during estrus. The present study followed 42 females as for the presentation of the vaginal occlusive membrane. Once the membranes ruptured spontaneously, a swab was collected to study vaginal cytology. Membrane rupture was observed in 39 females; six females showed membrane rupture with less than 21 days of age (17 to 21 days). Twenty-three females were characterized as being in estrus due to cytology showing a prevalence of anucleated superficial cells. One of these females was younger than 21 days old. The opening of the vaginal occlusive membrane took place most frequently in intervals between 17 and 18 days, and the membrane remained open between one and three consecutive days. It was possible to follow three cycles of membrane opening on six females. The present study showed the need to adapt handling guidelines for C. porcellus kept in research animal facilities. The early age of puberty imposes the need of separate the female daughters from their fathers at 16 days old.

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Lameness is a painful clinical condition of the bovine locomotor system that results in alterations of movement. Together with mastitis and infertility, lameness is the main welfare, health, and production problem found in intensive dairy farms worldwide. The clinical assessment of lameness results in an imprecise diagnosis and delayed intervention. Hence, the current approach to the problem is palliative rather than preventive. The five main surfaces used in free housing systems in dairy farms are two natural (grass and sand) and three artificial (rubber, asphalt, and concrete). Each surface presents a different risk potential for lameness, with grass carrying the lowest threat. The aim of the present study is to evaluate the flooring type influences on cows' movement capabilities, using all the available information relating to kinematics, kinetics, behavior, and posture in free-housed dairy cows. Inspired by a refurbished movement ecology concept, we conducted a literature review, taking into account kinematics, kinetics, behavior, and posture parameters by reference to the main surfaces used in free housing systems for dairy cows. We built an integrative analysis of functional ranges (IAFuR), which provides a combined welfare status diagram for the optimal (i.e., within the upper and lower limit) functional ranges for movement (i.e., posture, kinematics, and kinetics), navigation (i.e., behavior), and recovery capacities (i.e., metabolic cost). Our analysis confirms grass' outstanding clinical performance, as well as for all of the movement parameters measured. Grass boosts pedal joint homeostasis; provides reliable, safe, and costless locomotion; promotes longer resting times. Sand is the best natural alternative surface, but it presents an elevated metabolic cost. Rubber is an acceptable artificial alternative surface, but it is important to consider the mechanical and design properties. Asphalt and concrete surfaces are the most harmful because of the high traffic abrasiveness and loading impact. Furthermore, IAFuR can be used to consider other qualitative and quantitative parameters and to provide recommendations on material properties and the design of any surface, so as to move towards a more grass-like feel. We also suggest the implementation of a decision-making pathway to facilitate the interpretation of movement data in a more comprehensive way, in order to promote consistent, adaptable, timely, and adequate management decisions.

RESUMO

In digital curation, data are essential for actions, enabling better administrative management and greater efficiency in a sector or activity. In a research animal facility, the collection of management data associated with management systems or control sheets is the basis for ensuring quality information that subsidizes research and generates performance indicators and the needs and challenges to be transposed in the breeding and maintenance of animals. The inconsistency of data or incomplete records compromises the choices adopted in husbandry management practices or the interpretation of research results. For this reason, a survey was carried out about software available on the market that helps laboratory animal facilities with the management regarding software used in non-human primate breeding institutions (NHP) for scientific or conservation purposes. We identified 38 software that supports the handling of lab animals used in biomedical research; most of them with functionalities of environmental control (63.15%), control of animal files/tags (63.15%), and control of reproductive management (60%) and only two software related to the management of nonhuman primates kept under human care in research institutions. Regarding the tools used to manage the breeding of non-human primates in captivity in Brazilian institutions, five of the institutions questioned and reported that none currently uses software for colony management. In conclusion, there are several software for managing laboratory animals, but most of them are geared toward the management of rodent animal facilities. There is a lack of specific software on the market for use in animal facilities managing non-human primate breeding, which indicates the need for software developed to meet the management needs of animal facilities for these facilities.

Assuntos

RESUMO

Lab animals, such as Guinea pigs (Cavia porcellus), are crucial for scientific development, as they play an important role in the development and quality control chain of vaccines and drugs distributed by the Brazilian public health system. Investigating their biological and physiological parameters is fundamental to raise and keep these animals, so the handling of the facilities that hold them can be updated whenever new information comes up, with the well-being of the animals and alignment with the 3 Rs in mind. In the search for understanding reproductive aspects of Guinea pigs, the present study had the main goal of studying puberty by means of estrous cycle analysis in short-haired Guinea pigs. Guinea pigs have a vaginal occlusive membrane that covers the vaginal orifice. Its rupture takes place gradually and naturally, moments before labor and during estrus. The present study followed 42 females as for the presentation of the vaginal occlusive membrane. Once the membranes ruptured spontaneously, a swab was collected to study vaginal cytology. Membrane rupture was observed in 39 females; six females showed membrane rupture with less than 21 days of age (17 to 21 days). Twenty-three females were characterized as being in estrus due to cytology showing a prevalence of anucleated superficial cells. One of these females was younger than 21 days old. The opening of the vaginal occlusive membrane took place most frequently in intervals between 17 and 18 days, and the membrane remained open between one and three consecutive days. It was possible to follow three cycles of membrane opening on six females. The present study showed the need to adapt handling guidelines for C. porcellus kept in research animal facilities. The early age of puberty imposes the need of separate the female daughters from their fathers at 16 days old.(AU)

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Diante de uma demanda crescente em relação ao bem-estar animal, técnicas e pesquisas necessitam de suporte teórico para compreender e intervir em comportamentos descritos como anômalos ou distúrbios de conduta. Tendo em vista a prevenção do prejuízo ao organismo e os efeitos colaterais provenientes de uma condição de baixo nível de bem-estar, compreender como um comportamento anormal surge no repertório de um indivíduo é imprescindível para intervenções eficazes. O objetivo deste artigo é discutir dois modelos teóricos de áreas distintas do conhecimento, mas que possuem em comum o estudo do comportamento, a Etologia e o Behaviorismo Radical. A partir do modelo de Comportamento Apetitivo da Etologia e do Comportamento Adjuntivo do Behaviorismo, é possível compreender os mecanismos fisiológicos e funcionais que envolvem os distúrbios de comportamento.

Faced a growing demand for animal welfare, techniques and research need a theoretical support to understand and intervene in behaviors described as anomalous or behavioral disorders. In order to prevent damage to the body and the side effects arising from a low level of well-being, understanding how abnormal behavior appears in an individual's repertoire is essential for effective interventions. The aim of this article is to discuss two theoretical models from different areas of knowledge, but which have in common the study of behavior, Ethology and Radical Behaviorism. From the Appetitive Behavior model of ethology and the Adjunctive Behavior of Behaviorism, it is possible to understand the physiological and functional mechanisms that involve behavioral disorders.

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Diante do interesse científico e social para a construção e consolidação de instrumentos e procedimentos de avaliação de bem-estar, suas implicações teóricas acabam se mostrando controversas diante dos distintos modelos teóricos que estudam o comportamento animal, a destacar a atual ciência do bem-estar de inclinação cognitiva e o behaviorismao radical. É notóri a participação de influências cognitivas nas produções científicas em bem-estar animal, bem como as dificuldades em identificar e comprovar os estados cognitivos como mediadores e controladores de emoções, sentimentos e comportamentos. Neste viés, em oposição aos modelos cognitivos, o Behaviorismo Radical de Skinner critica as explicações que não podem ser alvo de investigação de uma ciência natural, e rejeita os estados cognitivos como causas do comportamento. Portanto, objetiva-se com este artigo apresentar uma visão do Behaviorismo Radical para questões emergentes em bem-estar animal discutidas por um viés cognitivo.

In view of the scientific and social interest for the construction and consolidation of instruments and procedures for the assessment of well-being, its theoretical implications end up being controversial in view of the different theoretical models that study animal behavior, highlighting the current science of well-being. cognitive inclination and radical behaviorism. The participation of cognitive influences in scientific productions in animal welfare is well known, as well as the difficulties in identifying and proving cognitive states as mediators and controllers of emotions, feelings and behaviors. In this vein, as opposed to cognitive models, Skinner's Radical Behaviorism criticizes explanations that cannot be investigated by a natural science, and rejects cognitive states as causes of behavior. Therefore, the aim of this article is to present a vision of Radical Behaviorism for emerging issues in animal welfare discussed by a cognitive bias.

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RESUMO

Diante de uma demanda crescente em relação ao bem-estar animal, técnicas e pesquisas necessitam de suporte teórico para compreender e intervir em comportamentos descritos como anômalos ou distúrbios de conduta. Tendo em vista a prevenção do prejuízo ao organismo e os efeitos colaterais provenientes de uma condição de baixo nível de bem-estar, compreender como um comportamento anormal surge no repertório de um indivíduo é imprescindível para intervenções eficazes. O objetivo deste artigo é discutir dois modelos teóricos de áreas distintas do conhecimento, mas que possuem em comum o estudo do comportamento, a Etologia e o Behaviorismo Radical. A partir do modelo de Comportamento Apetitivo da Etologia e do Comportamento Adjuntivo do Behaviorismo, é possível compreender os mecanismos fisiológicos e funcionais que envolvem os distúrbios de comportamento.(AU)

Faced a growing demand for animal welfare, techniques and research need a theoretical support to understand and intervene in behaviors described as anomalous or behavioral disorders. In order to prevent damage to the body and the side effects arising from a low level of well-being, understanding how abnormal behavior appears in an individual's repertoire is essential for effective interventions. The aim of this article is to discuss two theoretical models from different areas of knowledge, but which have in common the study of behavior, Ethology and Radical Behaviorism. From the Appetitive Behavior model of ethology and the Adjunctive Behavior of Behaviorism, it is possible to understand the physiological and functional mechanisms that involve behavioral disorders.(AU)

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RESUMO

A COVID-19 é uma nova coronovirose que demonstrou seu potencial pandêmico a partir de um surto observado em dezembro de 2019 na cidade de Wuhan, na China e, atualmente, já está sendo compreendida como uma síndrome de disfunção múltipla de órgãos, além dos pulmões. Até o momento, há ainda muito a se conhecer sobre o vírus, suas interações e potencial de transmissão, bem como a patogênese da doença; o desenvolvimento das candidatas a vacinas, terapias, diagnósticos mais precisos e ferramentas de controle da doença. Um dos principais desafios encontrados atualmente na pesquisa em COVID-19 é a disponibilização de modelos animais que mimetize a fisiopatogênese da doença humana. Sendo assim, este artigo objetiva fazer uma revisão não só do estado da arte em estudos pré-clínicos desenvolvidos para entendimento e enfrentamento da COVID-19 com a participação de diversos modelos animais de experimentação no aprimoramento de terapias imunes, mas também trazer à discussão a participação de espécies animais selvagens na origem da pandemia, ciclo de transmissão e manutenção da doença. De acordo com a revisão dos trabalhos publicados, foi possível observar que algumas espécies, como primatas não humanos e camundongos têm potencial de uso em múltiplas formas de experimentação, enquanto outras se limitam a um tipo de observação. Desta forma, a avaliação contínua de bons modelos animais para estudo da COVID-19 consolida a importância da investigação em animais e dos estudos pré-clínicos para solucionar esta e próximas pandemias que possam vir a ocorrer na história da saúde pública mundial.

COVID-19 is a new virus disease that demonstrated its pandemic potential from an outbreak observed in December 2019, in Wuhan, China and it is now considered as a multiple organ dysfunction syndrome, in addition to the lungs. So far, there is still much to know about the virus, its interactions and potential for transmission, as well as the pathogenesis of the disease; the development of vaccines candidates, therapies, more accurate diagnoses and disease control tools. One of the main challenges currently found in research in COVID-19 is the availability of animal models that mimic the pathophysiology of human disease. Therefore, this article aims to review not only the state of the art in preclinical studies developed to understand and confront COVID-19 with participation of several animal models of experimentation in the improvement of immune therapies, but also to bring to discussion the participation of wild animal species in the origin of the pandemic, transmission cycle and maintenance of the disease. According to this review, it was possible to observe that some species, such as non-human primates and mice, have potential for use in multiple forms of experimentation, while others are limited to one type of observation. Thus, the continuous evaluation of good animal models for COVID-19 studies consolidates the importance of animal research and preclinical studies to solve this and the next pandemics that may occur in the history of public health worldwide.

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A COVID-19 é uma nova coronovirose que demonstrou seu potencial pandêmico a partir de um surto observado em dezembro de 2019 na cidade de Wuhan, na China e, atualmente, já está sendo compreendida como uma síndrome de disfunção múltipla de órgãos, além dos pulmões. Até o momento, há ainda muito a se conhecer sobre o vírus, suas interações e potencial de transmissão, bem como a patogênese da doença; o desenvolvimento das candidatas a vacinas, terapias, diagnósticos mais precisos e ferramentas de controle da doença. Um dos principais desafios encontrados atualmente na pesquisa em COVID-19 é a disponibilização de modelos animais que mimetize a fisiopatogênese da doença humana. Sendo assim, este artigo objetiva fazer uma revisão não só do estado da arte em estudos pré-clínicos desenvolvidos para entendimento e enfrentamento da COVID-19 com a participação de diversos modelos animais de experimentação no aprimoramento de terapias imunes, mas também trazer à discussão a participação de espécies animais selvagens na origem da pandemia, ciclo de transmissão e manutenção da doença. De acordo com a revisão dos trabalhos publicados, foi possível observar que algumas espécies, como primatas não humanos e camundongos têm potencial de uso em múltiplas formas de experimentação, enquanto outras se limitam a um tipo de observação. Desta forma, a avaliação contínua de bons modelos animais para estudo da COVID-19 consolida a importância da investigação em animais e dos estudos pré-clínicos para solucionar esta e próximas pandemias que possam vir a ocorrer na história da saúde pública mundial.(AU)

COVID-19 is a new virus disease that demonstrated its pandemic potential from an outbreak observed in December 2019, in Wuhan, China and it is now considered as a multiple organ dysfunction syndrome, in addition to the lungs. So far, there is still much to know about the virus, its interactions and potential for transmission, as well as the pathogenesis of the disease; the development of vaccines candidates, therapies, more accurate diagnoses and disease control tools. One of the main challenges currently found in research in COVID-19 is the availability of animal models that mimic the pathophysiology of human disease. Therefore, this article aims to review not only the state of the art in preclinical studies developed to understand and confront COVID-19 with participation of several animal models of experimentation in the improvement of immune therapies, but also to bring to discussion the participation of wild animal species in the origin of the pandemic, transmission cycle and maintenance of the disease. According to this review, it was possible to observe that some species, such as non-human primates and mice, have potential for use in multiple forms of experimentation, while others are limited to one type of observation. Thus, the continuous evaluation of good animal models for COVID-19 studies consolidates the importance of animal research and preclinical studies to solve this and the next pandemics that may occur in the history of public health worldwide.(AU)

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RESUMO

Domestic geese are birds of zootechnical interest commonly created for ornamentation and guard in farms but are also useful for biomedical research, once they supply blood as a byproduct for laboratory analysis. The study aimed to contribute to the completion of health data available on these animals to trace a hematological profile of domestic geese that supply blood for research and provide data on the influence of periodic collections to the health of these animals. Ten Chinese geese (Anser domesticus), white and males, were kept in a research center installation. Four blood samples were performed weekly after the 1st collection, the sample with greater volume was sent to the laboratories of the Evandro Chagas Institute to be used in the arbovirus tests. The hematological evaluations observed values of packed cell volume (PCV), total number of erythrocytes (Hm), total number of leukocytes (Lc) and differential leukocyte count and the number of thrombocytes (Tb). All the animals were weighed and correlation of volume of blood collected from the animals weight was performed. No differences were found among the means obtained in the hematological values of the 1st collection and the subsequent collections demonstrating that the periodic collection in geese, when performed in obedience to the correlation between animals weight and blood volume, does not cause significant alterations in the animals hematological profile. The results of the hematological profile obtained in this study will add to the biological data of species available allowing a better health assessment of these animals in the creation of environments and in animal research facilities.(AU)

Assuntos

RESUMO

Domestic geese are birds of zootechnical interest commonly created for ornamentation and guard in farms but are also useful for biomedical research, once they supply blood as a byproduct for laboratory analysis. The study aimed to contribute to the completion of health data available on these animals to trace a hematological profile of domestic geese that supply blood for research and provide data on the influence of periodic collections to the health of these animals. Ten Chinese geese (Anser domesticus), white and males, were kept in a research center installation. Four blood samples were performed weekly after the 1st collection, the sample with greater volume was sent to the laboratories of the Evandro Chagas Institute to be used in the arbovirus tests. The hematological evaluations observed values of packed cell volume (PCV), total number of erythrocytes (Hm), total number of leukocytes (Lc) and differential leukocyte count and the number of thrombocytes (Tb). All the animals were weighed and correlation of volume of blood collected from the animals weight was performed. No differences were found among the means obtained in the hematological values of the 1st collection and the subsequent collections demonstrating that the periodic collection in geese, when performed in obedience to the correlation between animals weight and blood volume, does not cause significant alterations in the animals hematological profile. The results of the hematological profile obtained in this study will add to the biological data of species available allowing a better health assessment of these animals in the creation of environments and in animal research facilities.

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RESUMO

INTRODUCTION: E. coli is a ubiquitous bacterium commonly used as a sentinel in antimicrobial resistance studies. Here, E. coli was isolated from three groups (sick calves, healthy calves and bedding material), to assess the presence of antimicrobial resistance, describe resistance profiles, and compare these resistances among groups. MATERIAL AND METHODS: Samples were collected from calves and calving pens from 20 dairy farms. Using the disc diffusion method, E. coli isolates were screened for antimicrobial resistance against seven antimicrobials: Amoxicillin, Ceftiofur, Gentamicin, Enrofloxacin, Trimethoprim-sulfamethoxazole, Florfenicol and Oxytetracycline. Isolates resistant to all these seven antimicrobials were tested again against an extended 19 antimicrobial drug panel and for the presence of the most common E. coli pathogenicity genes through PCR. RESULTS & DISCUSSION: Three hundred forty-nine E. coli isolates were obtained; most isolates were resistant to a single antimicrobial, but 2.3% (8) were resistant to 16 to 19 of the antimicrobials tested. The group with the highest percentage of multiresistant isolates was the calves with diarrhea group. Younger calves provided samples with higher antimicrobial resistance levels. CONCLUSIONS: There is a high rate of antimicrobial resistance in dairy farms calving pens. These bacteria could not only be a resistance gene reservoir, but also could have the potential to spread these determinants through horizontal gene transfer to other susceptible bacteria. Measures should be taken to protect colonization of younger calves, based on hygienic measures and proper management.