Intra-myocardial dissecting hematoma: late complication of cocaine-induced myocardial infarction

Intra-myocardial dissecting hematoma (IDH) is a rare and unusual form of myocardial rupture that can be secondary to complicate acute myocardail infarction (MI). It is usually caused by a hemorrhagic dissection between the layers of myocardial fibers that can occur during the acute injury or the remodeling process. This case demonstrates a patient with a history of cocaine-induced ischemic cardiomyopathy complicated with an extensive IDH. Case description A 38-year-old man with a past medical history of hypertension, heart failure with reduced ejection fraction (HFrEF), and cocaine abuse disorder, presents to the emergency department complaining of worsening shortness of breath. Six months before the current hospitalization, the patient had been diagnosed with acute myocardial infarction, left heart Cath showed a severe three-vessel coronary artery disease, but it was non-suitable for revascularization. The transthoracic echocardiogram (TTE) showed significant left ventricular dysfunction with an ejection fraction of 28% and a thrombus in the left ventricle. Four days before the current admission, the patient started complaining of worsening exertional dyspnea, orthopnea, and peripheral edema. His vital signs were BP 90 x 62mmhg, HR 104 bpm, SatO2 90% and afebrile. His physical examination revealed an increased jugular venous pressure, significant symmetric peripheral edema (3+/4), and cold extremities. Cardiac auscultation revealed a regular rhythm, S3, without murmrs. A pulmonary exam revealed bilateral crackles on the inferior 1/3 of the lungs. EKG showed sinus tachycardia and prior inferior necrosis. Renal function was normal, but lactate acid was elevated (2.6mg/dL). The patient was started with noninvasive ventilation, along with IV diuretic therapy, vasopressor, and inotropic support (dobutamine). A TTE was performed which showed an intra-myocardial dissecting hematoma in the inferior left ventricle (LV) wall, along with a large thrombus in the LV chamber and severe biventricular dysfunction (ejection fraction was 23%). Our patient responded well to the medical treatment. Due to his severely reduced left ventricular ejection fraction (LVEF), the IDH was managed conservatively. He was discharged on standard medication for HFrEF and oral anticoagulation. Discussion this case demonstrates IDH as a late complication following a cocaine-induced MI. Two-dimensional echocardiography is useful in the diagnosis of IDH as well as in ruling out potential differential diagnoses. Conservative treatment is a viable option, especially for those patients not suitable for cardiac revascularization with severely reduced left ventricular ejection.

COVID-19 impedimetric biosensor based on polypyrrole nanotubes, nickel hydroxide and VHH antibody fragment: specific, sensitive, and rapid viral detection in saliva samples.

SARS-CoV-2 rapid spread required urgent, accurate, and prompt diagnosis to control the virus dissemination and pandemic management. Several sensors were developed using different biorecognition elements to obtain high specificity and sensitivity. However, the task to achieve these parameters in combination with fast detection, simplicity, and portability to identify the biorecognition element even in low concentration remains a challenge. Therefore, we developed an electrochemical biosensor based on polypyrrole nanotubes coupled via Ni(OH)2 ligation to an engineered antigen-binding fragment of heavy chain-only antibodies (VHH) termed Sb#15. Herein we report Sb#15-His6 expression, purification, and characterization of its interaction with the receptor-binding domain (RBD) of SARS-CoV-2 in addition to the construction and validation of a biosensor. The recombinant Sb#15 is correctly folded and interacts with the RBD with a dissociation constant (KD) of 27.1 ± 6.4 nmol/L. The biosensing platform was developed using polypyrrole nanotubes and Ni(OH)2, which can properly orientate the immobilization of Sb#15-His6 at the electrode surface through His-tag interaction for the sensitive SARS-CoV-2 antigen detection. The quantification limit was determined as 0.01 pg/mL using recombinant RBD, which was expressively lower than commercial monoclonal antibodies. In pre-characterized saliva, both Omicron and Delta SARS-CoV-2 were accurately detected only in positive samples, meeting all the requirements recommended by the World Health Organization for in vitro diagnostics. A low sample volume of saliva is needed to perform the detection, providing results within 15 min without further sample preparations. In summary, a new perspective allying recombinant VHHs with biosensor development and real sample detection was explored, addressing the need for accurate, rapid, and sensitive biosensors.

Avaliação de dor torácica na unidade de emergência ­ é possível associar os escores de risco cardiovascualr (TIMI, HEART E GRACE) e a presença de placa obstrutiva na angiotomografia de coronárias? / Assessment of chest pain in the emergency unit ­ is it possible to associate cardiovascular risk scores (TIMI, HEART AND GRACE) and the presence of obstructive plaque on coronary computed tomography angiography?

INTRODUÇÃO: Estima-se que quatro milhões de pacientes sejam atendidos anualmente em serviços de emergência do Brasil com a queixa de dor torácica, dos quais apenas 10% serão diagnosticados com síndrome coronariana aguda. Nesse contexto, escores de risco cardiovascular, como TIMI, HEART e GRACE, são utilizados como ferramenta para avaliar a possibilidade de doença arterial coronária (DAC). Inicialmente validados para estimar risco de eventos cardíacos intra-hospitalares, a sua associação com a presença de placa obstrutiva é pouco conhecida. OBJETIVO: Correlacionar os achados na Angiotomografia de Coronárias (Angio-TC) e os escores de risco cardiovascular, nos pacientes atendidos com dor torácica no pronto-socorro de hospital terciário. METODOLOGIA: Estudo observacional retrospectivo, baseado na análise de prontuários, no período de janeiro de 2019 a dezembro de 2021. Foram incluídos pacientes atendidos em pronto-atendimento de hospital terciário com a queixa principal de dor torácica aguda com valores de troponina negativos e ECG sem achados isquêmicos, submetidos a Angio-TC. Lesões coronárias ateroscleróticas foram quantificadas quanto à proporção de estenose luminal, sendo consideradas significativas aquelas com estenose ≥ 50% da luz do vaso em ≥ 1 artéria epicárdica relevante. RESULTADOS: Foram avaliados 350 pacientes com idade média de 52,6±11,9 anos, sendo 50% mulheres (Tabela 1). Desses pacientes, 72 (20,6%) apresentaram lesão aterosclerótica significativa em Angio-TC. Sexo masculino (OR: 1,87; IC 95%: 1,08 ­ 3,26), idade > 52 anos (OR: 2,85; CI 95%: 1,6 ­ 5,07), diagnóstico de Diabetes Mellitus (OR 2,17; IC 95%: 1,12 ­ 4,2) e relato de angina típica (OR 2,17; IC 95%: 1,12 ­ 4,2) estiveram associados de forma independente à presença de placa obstrutiva. Mais de 90% dos pacientes com lesão significativa na Angio-TC, apresentavam escore GRACE e TIMI de baixo risco. O escore HEART < 4 foi calculado em 23,6% dos pacientes com placa obstrutiva (Figura 1). CONCLUSÕES: A avaliação baseada em características clínicas e nos escores de risco cardiovascular de forma isolada não se mostrou suficiente para excluir de forma segura o diagnóstico de doença arterial coronária. Dessa forma, a Angio-TC é ferramenta complementar importante para o diagnóstico de coronariopatia nos pacientes com dor torácica aguda, possibilitando o início precoce de terapêutica adequada para a prevenção de novos eventos cardiovasculares.

Development of polypyrrole (nano)structures decorated with gold nanoparticles toward immunosensing for COVID-19 serological diagnosis.

The rapid and reliable detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroconversion in humans is crucial for suitable infection control. In this sense, many studies have focused on increasing the sensibility, lowering the detection limits and minimizing false negative/positive results. Thus, biosensors based on nanoarchitectures of conducting polymers are promising alternatives to more traditional materials since they can hold improved surface area, higher electrical conductivity and electrochemical activity. In this work, we reported the analytical comparison of two different conducting polymers morphologies for the development of an impedimetric biosensor to monitor SARS-CoV-2 seroconversion in humans. Biosensors based on polypyrrole (PPy), synthesized in both globular and nanotubular (NT) morphology, and gold nanoparticles are reported, using a self-assembly monolayer of 3-mercaptopropionic acid and covalently linked SARS-CoV-2 Nucleocapsid protein. First, the novel hybrid materials were characterized by electron microscopy and electrochemical measurements, and the biosensor step-by-step construction was characterized by electrochemical and spectroscopic techniques. As a proof of concept, the biosensor was used for the impedimetric detection of anti-SARS-CoV-2 Nucleocapsid protein monoclonal antibodies. The results showed a linear response for different antibody concentrations, good sensibility and possibility to quantify 7.442 and 0.4 ng/mL of monoclonal antibody for PPy in the globular and NT morphology, respectively. The PPy-NTs biosensor was able to discriminate serum obtained from COVID-19 positive versus negative clinical samples and is a promising tool for COVID-19 immunodiagnostic, which can contribute to further studies concerning rapid, efficient, and reliable detections.

Habitat fragmentation in the Brazilian Atlantic Forest is associated with erosion of frog immunogenetic diversity and increased fungal infections.

Habitat fragmentation and infectious diseases threaten wildlife globally, but the interactions of these threats are poorly understood. For instance, while habitat fragmentation can impact genetic diversity at neutral loci, the impacts on disease-relevant loci are less well-studied. We examined the effects of habitat fragmentation in Brazil's Atlantic Forest on amphibian genetic diversity at an immune locus related to antigen presentation and detection (MHC IIB Exon 2). We used a custom high-throughput assay to sequence a fragment of MHC IIB and quantified Batrachochytrium dendrobatidis (Bd) infections in six frog species in two Atlantic Forest regions. Habitat fragmentation was associated with genetic erosion at MHC IIB Exon 2. This erosion was most severe in forest specialists. Significant Bd infections were detected only in one Atlantic Forest region, potentially due to relatively higher elevation. In this region, forest specialists showed an increase in both Bd prevalence and infection loads in fragmented habitats. Reduced population-level MHC IIB diversity was associated with increased Bd infection risk. On the individual level, MHC IIB heterozygotes exhibited a trend toward reduced Bd infection risk, although this was marginally non-significant. Our results suggest that habitat fragmentation increases Bd infection susceptibility in amphibians, mediated at least in part through erosion of immunogenetic diversity. Our findings have implications for management of fragmented populations in the face of emerging infectious diseases.

Geography, Host Genetics, and Cross-Domain Microbial Networks Structure the Skin Microbiota of Fragmented Brazilian Atlantic Forest Frog Populations.

The host-associated microbiome plays a significant role in health. However, the roles of factors such as host genetics and microbial interactions in determining microbiome diversity remain unclear. We examined these factors using amplicon-based sequencing of 175 Thoropa taophora frog skin swabs collected from a naturally fragmented landscape in southeastern Brazil. Specifically, we examined (1) the effects of geography and host genetics on microbiome diversity and structure; (2) the structure of microbial eukaryotic and bacterial co-occurrence networks; and (3) co-occurrence between microeukaryotes with bacterial OTUs known to affect growth of the fungal pathogen Batrachochytrium dendrobatidis (Bd). While bacterial alpha diversity varied by both site type and host MHC IIB genotype, microeukaryotic alpha diversity varied only by site type. However, bacteria and microeukaryote composition showed variation according to both site type and host MHC IIB genotype. Our network analysis showed the highest connectivity when both eukaryotes and bacteria were included, implying that ecological interactions may occur among domains. Lastly, anti-Bd bacteria were not broadly negatively co-associated with the fungal microbiome and were positively associated with potential amphibian parasites. Our findings emphasize the importance of considering both domains in microbiome research and suggest that for effective probiotic strategies for amphibian disease management, considering potential interactions among all members of the microbiome is crucial.

Development and characterization of a novel liquid crystalline system containing sodium alginate for incorporation of trans-resveratrol intended for treatment of buccal candidiasis.

Trans-resveratrol has antimicrobial effects; however, its hydrophobic properties hamper its incorporation into pharmaceutical formulations. The aim of this study was to develop liquid crystals and a liquid crystal precursor (microemulsion), a common nanotechnology-based drug delivery system using a surfactant, an oil phase, and a polymer dispersion, for topical administration against buccal candidiasis. A ternary diagram was constructed and a potential formulation was selected, in order to run characterization tests. We chose the formulation that presented microemulsion and crystal liquid characteristics through polarized light microscopy and smallangle X-ray scattering experiments. The stability and structural features of the formulations were observed by performing rheological assay, measuring mucoadhesion, and analyzing texture profiles. It was verified that the chosen system was capable of transiting from microemulsion to liquid crystals when added in aqueous phase; further, the presence of sodium alginate as the polymer increased its mucoadhesion strength. Microbiological assay of trans-resveratrol, using amphotericin B and fluconazole as controls against strains of Candida albicans, showed positive anti-microbiological effect; however, a high concentration of the compound was needed.

Gene expression varies within and between enzootic and epizootic lineages of Batrachochytrium dendrobatidis (Bd) in the Americas.

While much research focus is paid to hypervirulent fungal lineages during emerging infectious disease outbreaks, examining enzootic pathogen isolates can be equally fruitful in delineating infection dynamics and determining pathogenesis. The fungal pathogen of amphibians, Batrachochytrium dendrobatidis (Bd), exhibits markedly different patterns of disease in natural populations, where it has caused massive amphibian declines in some regions, yet persists enzootically in others. Here we compare in vitro gene expression profiles of a panel of Bd isolates representing both the enzootic Bd-Brazil lineage, and the more recently diverged, panzootic lineage, Bd-GPL. We document significantly different lineage-specific and intralineage gene expression patterns, with Bd-Brazil upregulating genes with aspartic-type peptidase activity, and Bd-GPL upregulating CBM18 chitin-binding genes, among others. We also find pronounced intralineage variation in membrane integrity and transmembrane transport ability within our Bd-GPL isolates. Finally, we highlight unexpectedly divergent expression profiles in sympatric panzootic isolates, underscoring microgeographic functional variation in a largely clonal lineage. This variation in gene expression likely plays an important role in the relative pathogenesis and host range of Bd-Brazil and Bd-GPL isolates. Together, our results demonstrate that functional genomics approaches can provide information relevant to studies of virulence evolution within the Bd clade.

Skin-associated lactic acid bacteria from North American bullfrogs as potential control agents of Batrachochytrium dendrobatidis.

The fungal pathogen Batrachochytrium dendrobatidis (Bd) is the causative agent of chytridiomycosis and has been a key driver in the catastrophic decline of amphibians globally. While many strategies have been proposed to mitigate Bd outbreaks, few have been successful. In recent years, the use of probiotic formulations that protect an amphibian host by killing or inhibiting Bd have shown promise as an effective chytridiomycosis control strategy. The North American bullfrog (Lithobates catesbeianus) is a common carrier of Bd and harbours a diverse skin microbiota that includes lactic acid bacteria (LAB), a microbial group containing species classified as safe and conferring host benefits. We investigated beneficial/probiotic properties: anti-Bd activity, and adhesion and colonisation characteristics (hydrophobicity, biofilm formation and exopolysaccharide-EPS production) in two confirmed LAB (cLAB-Enterococcus gallinarum CRL 1826, Lactococcus garvieae CRL 1828) and 60 presumptive LAB (pLAB) [together named as LABs] isolated from bullfrog skin.We challenged LABs against eight genetically diverse Bd isolates and found that 32% of the LABs inhibited at least one Bd isolate with varying rates of inhibition. Thus, we established a score of sensitivity from highest (BdGPL AVS7) to lowest (BdGPL C2A) for the studied Bd isolates. We further reveal key factors underlying host adhesion and colonisation of LABs. Specifically, 90.3% of LABs exhibited hydrophilic properties that may promote adhesion to the cutaneous mucus, with the remaining isolates (9.7%) being hydrophobic in nature with a surface polarity compatible with colonisation of acidic, basic or both substrate types. We also found that 59.7% of LABs showed EPS synthesis and 66.1% produced biofilm at different levels: 21% weak, 29% moderate, and 16.1% strong. Together all these properties enhance colonisation of the host surface (mucus or epithelial cells) and may confer protective benefits against Bd through competitive exclusion. Correspondence analysis indicated that biofilm synthesis was LABs specific with high aggregating bacteria correlating with strong biofilm producers, and EPS producers being correlated to negative biofilm producing LABs. We performed Random Amplified Polymorphic DNA (RAPD)-PCR analysis and demonstrated a higher degree of genetic diversity among rod-shaped pLAB than cocci. Based on the LAB genetic analysis and specific probiotic selection criteria that involve beneficial properties, we sequenced 16 pLAB which were identified as Pediococcus pentosaceus, Enterococcus thailandicus, Lactobacillus pentosus/L. plantarum, L. brevis, and L. curvatus. Compatibility assays performed with cLAB and the 16 species described above indicate that all tested LAB can be included in a mixed probiotic formula. Based on our analyses, we suggest that E. gallinarum CRL 1826, L. garvieae CRL 1828, and P. pentosaceus 15 and 18B represent optimal probiotic candidates for Bd control and mitigation.

Neuroaxonal Dystrophy in a mule: first case reported / Distrofia neuroaxonal em muar: primeiro relato de caso

A 12-month-old mule (sterile hybrid equine species) presented unspecific neurological changes (symmetric ataxia, dysmetria, conscious proprioceptive deficit and weakness). Due to poor prognosis and to the fact that a sibling from the previous generation exhibited similar clinical signs that were not definitively diagnosed, the animal was euthanized. Diagnosis of neuroaxonal dystrophy was confirmed by anatomohistopathological analysis. This is the first clinical case of neuronal dystrophy in a mule reported in the world. The clinical and histopathological characteristics of this disease were very similar to those reported for several equine breeds. Therefore, the disease should also be considered in the diagnosis of neurological conditions in mules and donkeys.(AU)

Relata-se o caso de uma mula de 12 meses que apresentou alterações neurológicas inespecíficas (ataxia simétrica, dismetria, déficit proprioceptivo consciente e fraqueza). Devido ao mau prognóstico e ao fato de um irmão da geração anterior apresentar sinais clínicos similares sem diagnóstico conclusivo, o animal foi eutanasiado. O diagnóstico de distrofia neuroaxonal foi confirmado por análise anátomo-histopatológica. Esse é o primeiro caso clínico de distrofia neuroaxonal em muar relatado no mundo. As características clínicas e histopatológicas dessa doença foram muito semelhantes às relatadas em várias raças de equinos. Portanto, a doença também deve ser considerada no diagnóstico de condições neurológicas em muares e asininos.(AU)

Neuroaxonal Dystrophy in a mule: first case reported / Distrofia neuroaxonal em muar: primeiro relato de caso

A 12-month-old mule (sterile hybrid equine species) presented unspecific neurological changes (symmetric ataxia, dysmetria, conscious proprioceptive deficit and weakness). Due to poor prognosis and to the fact that a sibling from the previous generation exhibited similar clinical signs that were not definitively diagnosed, the animal was euthanized. Diagnosis of neuroaxonal dystrophy was confirmed by anatomohistopathological analysis. This is the first clinical case of neuronal dystrophy in a mule reported in the world. The clinical and histopathological characteristics of this disease were very similar to those reported for several equine breeds. Therefore, the disease should also be considered in the diagnosis of neurological conditions in mules and donkeys.(AU)

Relata-se o caso de uma mula de 12 meses que apresentou alterações neurológicas inespecíficas (ataxia simétrica, dismetria, déficit proprioceptivo consciente e fraqueza). Devido ao mau prognóstico e ao fato de um irmão da geração anterior apresentar sinais clínicos similares sem diagnóstico conclusivo, o animal foi eutanasiado. O diagnóstico de distrofia neuroaxonal foi confirmado por análise anátomo-histopatológica. Esse é o primeiro caso clínico de distrofia neuroaxonal em muar relatado no mundo. As características clínicas e histopatológicas dessa doença foram muito semelhantes às relatadas em várias raças de equinos. Portanto, a doença também deve ser considerada no diagnóstico de condições neurológicas em muares e asininos.(AU)

Globally invasive genotypes of the amphibian chytrid outcompete an enzootic lineage in coinfections.

Competition between genotypes is likely to be a key driver of pathogen evolution, particularly following a geographical invasion by distant strains. Theory predicts that competition between disease strains will result in the most virulent strain persisting. Despite its evolutionary implications, the role of strain competition in shaping populations remains untested for most pathogens. We experimentally investigated the in vivo competitive differences between two divergent lineages of the amphibian-killing chytrid fungus ( Batrachochytrium dendrobatidis, Bd). These Bd lineages are hypothesized to have diverged in allopatry but been recently brought back into secondary contact by human introduction. Prior studies indicate that a panzootically-distributed, global lineage of Bd was recently introduced into southern Brazil, and is competitively excluding enzootic lineages in the southern Atlantic Forest. To test for differences in competitive ability between invasive and enzootic Brazilian Bd isolates, we coinfected a model host frog system which we developed for this study ( Hymenochirus curtipes). We tracked isolate-specific zoospore production over the course of the coinfection experiment with chip-based digital PCR (dPCR). The globally invasive panzootic lineage had a competitive advantage in spore production especially during the first one to four weeks of infection, and on frogs that eventually succumbed to Bd infection. Our study provides new evidence that competitive pressure resulting from the human movement of pathogen strains can rapidly alter the genetics, community dynamics and spatial epidemiology of pathogens in the wild.

Temperament, behavior, body temperature, heart and respiratory rate of sheep trained with tactile stimulation and halter walking / Temperamento, comportamento, temperatura corporal, frequência cardíaca e respiratória de ovinos treinados com estímulo tátil e deslocamento com auxílio de cabresto

O objetivo desse estudo foi avaliar a influência dos treinamentos com estímulo tátil e deslocamento com auxílio de cabresto no temperamento, fisiologia, comportamento e peso corporal de ovinos. Um total de 80 ovinos, machos e fêmeas, das raças Morada Nova (MN) e Santa Inês (SI), com idade inicial de seis a oito meses, foram treinados com estímulo tátil (TS), deslocamento com auxílio de cabresto (HW) ou estímulo tátil e deslocamento com auxílio de cabresto (TS+HW). Os animais do grupo controle (C) não foram submetidos a nenhum tipo de treinamento. Os aspectos comportamentais foram mensurados no teste de campo aberto, para quantificar as variáveis movimentação, vocalização, tentativa de fuga e cavar chão, enquanto no teste de temperamento foram dados escores de temperamento para cada animal. Os animais foram pesados e foram aferidas as temperaturas retais, frequências cardíacas e respiratórias. Os machos foram mais reativos ao humano do que as fêmeas. Os animais treinados com TS foram menos reativos no teste de temperamento, enquanto os animais mais reativos eram machos SI dos tratamentos C e TS+HW. Machos dos tratamentos C e HW foram os mais pesados durante o estudo. Os animais do grupo controle mostraram maiores médias para frequência cardíaca e temperatura retal, enquanto animais treinados com TS e HW mostraram os menores valores. Fêmeas MN treinadas com TS e TS+HW se movimentaram mais durante o teste de campo aberto, enquanto fêmeas SI do grupo controle se movimentaram menos. Os animais da raça SI vocalizaram mais durante o teste de campo aberto, tanto do tratamento C quanto do TS+HW. Os animais da raça MN do grupo C vocalizaram menos. Ovinos treinados com estímulo tátil se mostraram mais dóceis. O treinamento com estímulo tátil e deslocamento com auxílio de cabresto em ovinos das raças Morada Nova e Santa Inês influenciou a frequência cardíaca, a temperatura retal, a movimentação, a...

This study aimed to evaluate the influence of tactile stimulation and halter walking trainings in the temperament, physiology, behavior and body weight of sheep. A total of 80 sheep, males and females, of the Morada Nova (MN) and Santa Ines (SI) breeds, with initial ages of six to eight months, were trained with tactile stimulation (TS), halter walking (HW) or tactile stimulation and halter walking (TS+HW). The control (C) animals were not submitted to any kind of training. The behavioral aspects were measured by application of a open-field test, to quantify the traits movement, vocalization, escape attempt and digging, and the temperament test, with assignment of a temperament score for each animal. The animals were weighed and rectal temperature, heart rate and respiratory rate were measured. Males were more reactive than females to human. Animals trained with TS were the least reactive in the temperament test, while the most reactive animals were SI male from C and TS+HW treatments. Males of treatments C and HW were the heaviest during the study. The animals in the control group showed higher averages for heart rate and rectal temperature, while animals trained with TS and HW showed the lowest values. Females MN trained with TS and TS+HW moved more during the open-field test, while the SI females of the control group moved less. The SI animals vocalized more during the open-field test, both from treatment C and from TS+HW. The MN animals from C treatment vocalized less. Sheep trained with tactile stimulation were more docile. The training with tactile stimulation and halter walking in Santa Ines and Morada Nova sheep influenced the heart rate, rectal temperature, moviment, vocalization, escape attempt and body weight.

Operacionalização do conceito de resiliência de forrageiras sob pastoreio rotativo aos distúrbios de mudanças climáticas / Operationalization of the resilience concept the forrage under rotational grazing to climate change disturbances

The resilience of forage under rotational grazing to climate change disturbances, in particular the effects of dry spells is a basic attribute to achieve the sustainability of the dairy cattle production system. This work presents a method based on the system dynamics to estimate the indices of resilience: hardness, robustness, recovery rapidity, and elasticity. A meta-model for the management of the plant-animal ecosystem was adapted to simulate the effects of the disturbances caused by the dry spells in the dry matter stock in the paddocks. The in silico experiments results showed differences between the resilience of the two forage cultivars for the same magnitude of disturbance and differences due to the time of occurrence of water deficit in the forage growth phase or in the paddock use phase by the animals. The recovery rapidity index showed a conceptual adherence to the conditions of rotational grazing, due to the time required to define the entry and exit of the animals in the paddock. It was concluded that the operationalization and evaluation of the resilience generated information about the dry matter stock dynamics that are useful for rotational grazing planning.

A resiliência de forrageiras sob pastoreio rotativo aos distúrbios de mudanças climáticas, em particular aos efeitos do déficit hídrico em veranicos, é um atributo básico para alcançar a sustentabilidade do sistema de produção de leite. Este trabalho apresenta um método baseado na dinâmica de sistemas para estimar os índices de resiliência: dureza, robustez, rapidez de recuperação e elasticidade. Um metamodelo para o manejo do ecossistema planta-animal foi adaptado para simular os efeitos dos distúrbios causados por veranicos no estoque de matéria seca dos piquetes. Os resultados dos experimentos in silicomostram diferenças entre as resiliências de dois cultivares de forrageiras para uma mesma magnitude de distúrbio e diferenças devido a época de ocorrência do déficit hídrico ser na fase de crescimento da forrageira ou na fase de uso dos piquetes pelos animais. O índice de rapidez de recuperação mostrou aderência conceitual para as condições de pastoreio rotativo, devido à premência de tempo na definição da entrada e saída dos animais nos piquetes. Concluiu-se que a operacionalização e avaliação da resiliência geram informações sobre a dinâmica do estoque de matéria seca ofertada para os animais e que estas informações são úteis para o planejamento do pastoreio rotativo.

Operacionalização do conceito de resiliência de forrageiras sob pastoreio rotativo aos distúrbios de mudanças climáticas / Operationalization of the resilience concept the forrage under rotational grazing to climate change disturbances

The resilience of forage under rotational grazing to climate change disturbances, in particular the effects of dry spells is a basic attribute to achieve the sustainability of the dairy cattle production system. This work presents a method based on the system dynamics to estimate the indices of resilience: hardness, robustness, recovery rapidity, and elasticity. A meta-model for the management of the plant-animal ecosystem was adapted to simulate the effects of the disturbances caused by the dry spells in the dry matter stock in the paddocks. The in silico experiments results showed differences between the resilience of the two forage cultivars for the same magnitude of disturbance and differences due to the time of occurrence of water deficit in the forage growth phase or in the paddock use phase by the animals. The recovery rapidity index showed a conceptual adherence to the conditions of rotational grazing, due to the time required to define the entry and exit of the animals in the paddock. It was concluded that the operationalization and evaluation of the resilience generated information about the dry matter stock dynamics that are useful for rotational grazing planning.(AU)

A resiliência de forrageiras sob pastoreio rotativo aos distúrbios de mudanças climáticas, em particular aos efeitos do déficit hídrico em veranicos, é um atributo básico para alcançar a sustentabilidade do sistema de produção de leite. Este trabalho apresenta um método baseado na dinâmica de sistemas para estimar os índices de resiliência: dureza, robustez, rapidez de recuperação e elasticidade. Um metamodelo para o manejo do ecossistema planta-animal foi adaptado para simular os efeitos dos distúrbios causados por veranicos no estoque de matéria seca dos piquetes. Os resultados dos experimentos in silicomostram diferenças entre as resiliências de dois cultivares de forrageiras para uma mesma magnitude de distúrbio e diferenças devido a época de ocorrência do déficit hídrico ser na fase de crescimento da forrageira ou na fase de uso dos piquetes pelos animais. O índice de rapidez de recuperação mostrou aderência conceitual para as condições de pastoreio rotativo, devido à premência de tempo na definição da entrada e saída dos animais nos piquetes. Concluiu-se que a operacionalização e avaliação da resiliência geram informações sobre a dinâmica do estoque de matéria seca ofertada para os animais e que estas informações são úteis para o planejamento do pastoreio rotativo.(AU)

Temperament, behavior, body temperature, heart and respiratory rate of sheep trained with tactile stimulation and halter walking / Temperamento, comportamento, temperatura corporal, frequência cardíaca e respiratória de ovinos treinados com estímulo tátil e deslocamento com auxílio de cabresto

O objetivo desse estudo foi avaliar a influência dos treinamentos com estímulo tátil e deslocamento com auxílio de cabresto no temperamento, fisiologia, comportamento e peso corporal de ovinos. Um total de 80 ovinos, machos e fêmeas, das raças Morada Nova (MN) e Santa Inês (SI), com idade inicial de seis a oito meses, foram treinados com estímulo tátil (TS), deslocamento com auxílio de cabresto (HW) ou estímulo tátil e deslocamento com auxílio de cabresto (TS+HW). Os animais do grupo controle (C) não foram submetidos a nenhum tipo de treinamento. Os aspectos comportamentais foram mensurados no teste de campo aberto, para quantificar as variáveis movimentação, vocalização, tentativa de fuga e cavar chão, enquanto no teste de temperamento foram dados escores de temperamento para cada animal. Os animais foram pesados e foram aferidas as temperaturas retais, frequências cardíacas e respiratórias. Os machos foram mais reativos ao humano do que as fêmeas. Os animais treinados com TS foram menos reativos no teste de temperamento, enquanto os animais mais reativos eram machos SI dos tratamentos C e TS+HW. Machos dos tratamentos C e HW foram os mais pesados durante o estudo. Os animais do grupo controle mostraram maiores médias para frequência cardíaca e temperatura retal, enquanto animais treinados com TS e HW mostraram os menores valores. Fêmeas MN treinadas com TS e TS+HW se movimentaram mais durante o teste de campo aberto, enquanto fêmeas SI do grupo controle se movimentaram menos. Os animais da raça SI vocalizaram mais durante o teste de campo aberto, tanto do tratamento C quanto do TS+HW. Os animais da raça MN do grupo C vocalizaram menos. Ovinos treinados com estímulo tátil se mostraram mais dóceis. O treinamento com estímulo tátil e deslocamento com auxílio de cabresto em ovinos das raças Morada Nova e Santa Inês influenciou a frequência cardíaca, a temperatura retal, a movimentação, a...(AU)

This study aimed to evaluate the influence of tactile stimulation and halter walking trainings in the temperament, physiology, behavior and body weight of sheep. A total of 80 sheep, males and females, of the Morada Nova (MN) and Santa Ines (SI) breeds, with initial ages of six to eight months, were trained with tactile stimulation (TS), halter walking (HW) or tactile stimulation and halter walking (TS+HW). The control (C) animals were not submitted to any kind of training. The behavioral aspects were measured by application of a open-field test, to quantify the traits movement, vocalization, escape attempt and digging, and the temperament test, with assignment of a temperament score for each animal. The animals were weighed and rectal temperature, heart rate and respiratory rate were measured. Males were more reactive than females to human. Animals trained with TS were the least reactive in the temperament test, while the most reactive animals were SI male from C and TS+HW treatments. Males of treatments C and HW were the heaviest during the study. The animals in the control group showed higher averages for heart rate and rectal temperature, while animals trained with TS and HW showed the lowest values. Females MN trained with TS and TS+HW moved more during the open-field test, while the SI females of the control group moved less. The SI animals vocalized more during the open-field test, both from treatment C and from TS+HW. The MN animals from C treatment vocalized less. Sheep trained with tactile stimulation were more docile. The training with tactile stimulation and halter walking in Santa Ines and Morada Nova sheep influenced the heart rate, rectal temperature, moviment, vocalization, escape attempt and body weight.(AU)

Estimulação tátil em novilhas leiteiras: efeitos no comportamento e na produção de leite após o parto / Tactile stimulation of dairy heifers: effects on behavior and milk production after calving

O manejo positivo em novilhas primíparas antes do parto, realizado através de estímulos táteis, pode ser benéfico para o comportamento na rotina de ordenha. O objetivo do trabalho foi avaliar a utilização do estímulo tátil em novilhas leiteiras e seus efeitos no comportamento e produção de leite após o parto. Foram utilizadas 10 novilhas primíparas da raça Holandesa. Metade do grupo recebeu treinamento com estímulo tátil em todas as partes do corpo, enquanto a outra metade não recebeu estimulação (grupo controle). O período de treinamento foi dividido em três fases: inicial, do primeiro ao sexto dia; intermediário, do sétimo ao 12º dia, e final, do 13º ao 23º dia de treinamento. Durante o treinamento foram avaliados, por cinco minutos, movimentação e deslocamento por escores. Também foram registradas medidas fisiológicas [frequência respiratória (FR) e temperatura do olho mínima (TOmín) através da câmera termográfica]. Após o parto, as novilhas foram levadas para a primeira ordenha, quando foram iniciadas as avaliações durante os 10 primeiros dias de ordenha (20 ordenhas consecutivas). As avaliações comportamentais dos animais foram realizadas atribuindo-se escore de reatividade 1 (comportamentos desejáveis) e 2 (comportamentos indesejáveis): entrada na baia, assepsia dos tetos, ordenha de jato de leite para teste de mastite, momento de colocação das teteiras e processo de retirada do leite, além da quantidade de leite produzida. As médias da TOmín e da FR decresceram no decorrer do período de treinamento. Foi observada diferença significativa para o escore de deslocamento (P=0,019), com redução do deslocamento do período inicial para o final (60,0% para 25,7%). Na colocação das teteiras, as novilhas estimuladas apresentaram menor reatividade (P=0,002), com menor frequência de comportamento indesejável (12,0%), do que as novilhas não estimuladas (30,2%). A curva de produção de leite média para os primeiros 60 dias de lactação do grupo das novilhas...

The positive management of primiparous heifers before calving through tactile stimulation may have beneficial effects on behavior during routine milking. The objective of this study was to evaluate the use of tactile stimulation in dairy heifers and its effects on behavior and milk production after calving. Ten primiparous Holstein heifers were used. Half the group received training with tactile stimulation of all body regions, while the other group did not receive stimulation (control group). The training period was divided into three phases: early, days 1 to 6 of training; intermediate: days 7 to 12, and final, days 13 to 23. During training, movement and displacement scores were obtained over a period of 5 minutes. Physiological parameters were also recorded [respiratory rate (FR) and minimum eye temperature (ETmin) measured with a thermal imaging camera]. After calving, the heifers were submitted to first milking when the evaluations were started for the first 10 days of milking (20 consecutive milkings). The behavior of the animals was evaluated by attributing a reactivity score of 1 (desirable behaviors) or 2 (undesirable behaviors): entry into the pen, teat disinfection, milking one or two jets of milk for mastitis testing, attachment of teat cups, and removal of milk, as well as the amount of milk produced. Mean ETmin and FR decreased over the training period. A significant difference was observed for displacement score (P=0.019), with a reduction in displacement from the early to the final period (from 60.0% to 25.7%). During the attachment of teat cups, stimulated heifers were less reactive (P=0.002), characterized by a lower frequency of undesirable behaviors (12.0%), than unstimulated heifers (30.2%). The average milk yield during the first 60 days of lactation was higher for the group of stimulated heifers (Ln y=2.20–0.0102t+0.331lnt, R2=0.76) compared to unstimulated heifers (Ln y=1.54–0.0191x+0.578lnx, R2=0.79), with this...

Estimulação tátil em novilhas leiteiras: efeitos no comportamento e na produção de leite após o parto / Tactile stimulation of dairy heifers: effects on behavior and milk production after calving

O manejo positivo em novilhas primíparas antes do parto, realizado através de estímulos táteis, pode ser benéfico para o comportamento na rotina de ordenha. O objetivo do trabalho foi avaliar a utilização do estímulo tátil em novilhas leiteiras e seus efeitos no comportamento e produção de leite após o parto. Foram utilizadas 10 novilhas primíparas da raça Holandesa. Metade do grupo recebeu treinamento com estímulo tátil em todas as partes do corpo, enquanto a outra metade não recebeu estimulação (grupo controle). O período de treinamento foi dividido em três fases: inicial, do primeiro ao sexto dia; intermediário, do sétimo ao 12º dia, e final, do 13º ao 23º dia de treinamento. Durante o treinamento foram avaliados, por cinco minutos, movimentação e deslocamento por escores. Também foram registradas medidas fisiológicas [frequência respiratória (FR) e temperatura do olho mínima (TOmín) através da câmera termográfica]. Após o parto, as novilhas foram levadas para a primeira ordenha, quando foram iniciadas as avaliações durante os 10 primeiros dias de ordenha (20 ordenhas consecutivas). As avaliações comportamentais dos animais foram realizadas atribuindo-se escore de reatividade 1 (comportamentos desejáveis) e 2 (comportamentos indesejáveis): entrada na baia, assepsia dos tetos, ordenha de jato de leite para teste de mastite, momento de colocação das teteiras e processo de retirada do leite, além da quantidade de leite produzida. As médias da TOmín e da FR decresceram no decorrer do período de treinamento. Foi observada diferença significativa para o escore de deslocamento (P=0,019), com redução do deslocamento do período inicial para o final (60,0% para 25,7%). Na colocação das teteiras, as novilhas estimuladas apresentaram menor reatividade (P=0,002), com menor frequência de comportamento indesejável (12,0%), do que as novilhas não estimuladas (30,2%). A curva de produção de leite média para os primeiros 60 dias de lactação do grupo das novilhas...(AU)

The positive management of primiparous heifers before calving through tactile stimulation may have beneficial effects on behavior during routine milking. The objective of this study was to evaluate the use of tactile stimulation in dairy heifers and its effects on behavior and milk production after calving. Ten primiparous Holstein heifers were used. Half the group received training with tactile stimulation of all body regions, while the other group did not receive stimulation (control group). The training period was divided into three phases: early, days 1 to 6 of training; intermediate: days 7 to 12, and final, days 13 to 23. During training, movement and displacement scores were obtained over a period of 5 minutes. Physiological parameters were also recorded [respiratory rate (FR) and minimum eye temperature (ETmin) measured with a thermal imaging camera]. After calving, the heifers were submitted to first milking when the evaluations were started for the first 10 days of milking (20 consecutive milkings). The behavior of the animals was evaluated by attributing a reactivity score of 1 (desirable behaviors) or 2 (undesirable behaviors): entry into the pen, teat disinfection, milking one or two jets of milk for mastitis testing, attachment of teat cups, and removal of milk, as well as the amount of milk produced. Mean ETmin and FR decreased over the training period. A significant difference was observed for displacement score (P=0.019), with a reduction in displacement from the early to the final period (from 60.0% to 25.7%). During the attachment of teat cups, stimulated heifers were less reactive (P=0.002), characterized by a lower frequency of undesirable behaviors (12.0%), than unstimulated heifers (30.2%). The average milk yield during the first 60 days of lactation was higher for the group of stimulated heifers (Ln y=2.20–0.0102t+0.331lnt, R2=0.76) compared to unstimulated heifers (Ln y=1.54–0.0191x+0.578lnx, R2=0.79), with this...(AU)

Partitioning the net effect of host diversity on an emerging amphibian pathogen.

The 'dilution effect' (DE) hypothesis predicts that diverse host communities will show reduced disease. The underlying causes of pathogen dilution are complex, because they involve non-additive (driven by host interactions and differential habitat use) and additive (controlled by host species composition) mechanisms. Here, we used measures of complementarity and selection traditionally employed in the field of biodiversity-ecosystem function (BEF) to quantify the net effect of host diversity on disease dynamics of the amphibian-killing fungus Batrachochytrium dendrobatidis (Bd). Complementarity occurs when average infection load in diverse host assemblages departs from that of each component species in uniform populations. Selection measures the disproportionate impact of a particular species in diverse assemblages compared with its performance in uniform populations, and therefore has strong additive and non-additive properties. We experimentally infected tropical amphibian species of varying life histories, in single- and multi-host treatments, and measured individual Bd infection loads. Host diversity reduced Bd infection in amphibians through a mechanism analogous to complementarity (sensu BEF), potentially by reducing shared habitat use and transmission among hosts. Additionally, the selection component indicated that one particular terrestrial species showed reduced infection loads in diverse assemblages at the expense of neighbouring aquatic hosts becoming heavily infected. By partitioning components of diversity, our findings underscore the importance of additive and non-additive mechanisms underlying the DE.