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1.
Emerg Infect Dis ; 26(4)2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32186507

RESUMO

Gallibacterium anatis is an opportunistic pathogen, previously associated with deaths in poultry, domestic birds, and occasionally humans. We obtained G. anatis isolates from bronchoalveolar lavage samples of 10 calves with bronchopneumonia unresponsive to antimicrobial therapy. Collected isolates were multidrug-resistant to extensively drug-resistant, exhibiting resistance against 5-7 classes of antimicrobial drugs. Whole-genome sequencing revealed 24 different antimicrobial-resistance determinants, including genes not previously described in the Gallibacterium genus or even the Pasteurellaceae family, such as aadA23, blaCARB-8, tet(Y), and qnrD1. Some resistance genes were closely linked in resistance gene cassettes with either transposases in close proximity or situated on putative mobile elements or predicted plasmids. Single-nucleotide polymorphism genotyping revealed large genetic variation between the G. anatis isolates, including isolates retrieved from the same farm. G. anatis might play a hitherto unrecognized role as a respiratory pathogen and resistance gene reservoir in cattle and has unknown zoonotic potential.


Assuntos
Broncopneumonia , Pasteurellaceae , Animais , Bélgica , Broncopneumonia/epidemiologia , Broncopneumonia/veterinária , Bovinos , Doenças dos Bovinos , Resistência Microbiana a Medicamentos , Pasteurellaceae/genética
2.
J Clin Microbiol ; 58(6)2020 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-32229599

RESUMO

Mycoplasma bovis is a leading cause of pneumonia in modern calf rearing. Fast identification is essential to ensure appropriate antimicrobial therapy. Therefore, the objective of this study was to develop a protocol to identify M. bovis from bronchoalveolar lavage fluid (BALf) with matrix-assisted laser desorption ionization-time of flight mass spectrometry MALDI-TOF MS and to determine the diagnostic accuracy in comparison with other techniques. BALf was obtained from 104 cattle, and the presence of M. bovis was determined in the following three ways: (i) rapid identification of M. bovis with MALDI-TOF MS (RIMM) (BALf was enriched and after 24, 48, and 72 h of incubation and was analyzed using MALDI-TOF MS), (ii) triplex real-time PCR for M. bovis, Mycoplasma bovirhinis, and Mycoplasma dispar, and (iii) 10-day incubation on selective-indicative agar. The diagnostic accuracy of the three tests was determined with Bayesian latent class modeling (BLCM). After 24 h of enrichment, M. bovis was identified with MALDI-TOF MS in 3 out of 104 BALf samples. After 48 and 72 h of enrichment, 32/104 and 38/100 samples, respectively, were M. bovis positive. Lipase-positive Mycoplasma-like colonies were seen in 28 of 104 samples. Real-time PCR resulted in 28/104 positive and 12/104 doubtful results for M. bovis The BLCM showed a sensitivity (Se) and specificity (Sp) of 86.6% (95% credible interval [CI], 69.4% to 97.6%) and 86.4% (CI, 76.1 to 93.8) for RIMM. For real-time PCR, Se was 94.8% (CI, 89.9 to 97.9) and Sp was 88.9% (CI, 78.0 to 97.4). For selective-indicative agar, Se and Sp were 70.5% (CI, 52.1 to 87.1) and 93.9% (CI, 85.9 to 98.4), respectively. These results suggest that rapid identification of M. bovis with MALDI-TOF MS after an enrichment procedure is a promising test for routine diagnostics in veterinary laboratories.


Assuntos
Mycoplasma bovis , Animais , Teorema de Bayes , Líquido da Lavagem Broncoalveolar , Bovinos , Mycoplasma , Mycoplasma bovis/genética , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
3.
Vet Res ; 51(1): 54, 2020 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-32299498

RESUMO

In herds with Mycoplasma bovis circulation, colostrum is often considered infectious. However, in contrast to milk, the presence of M. bovis in colostrum was not previously evidenced. In this survey, the presence of M. bovis DNA was determined with real-time PCR in 368 colostrum samples from 17 herds, recently infected with M. bovis. Only 1.9% of the samples tested positive, with 13 herds having no positive samples and an overall within-herd prevalence of 3.2% (SD: 4.9%; Range: 0-30.0%). These results show that in infected herds M. bovis DNA can be retrieved in colostrum. To what extend colostrum is infectious remains to be determined.


Assuntos
Doenças dos Bovinos/epidemiologia , Colostro/microbiologia , Infecções por Mycoplasma/epidemiologia , Mycoplasma bovis/fisiologia , Animais , Bélgica/epidemiologia , Bovinos , Doenças dos Bovinos/microbiologia , Infecções por Mycoplasma/microbiologia , Prevalência , Reação em Cadeia da Polimerase em Tempo Real/veterinária
4.
BMC Vet Res ; 15(1): 167, 2019 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-31126282

RESUMO

BACKGROUND: Respiratory infections are the main indication for antimicrobial use in calves. As in humans and horses, studying inflammation of the deep airways by lung cytology raises the possibility of preventing respiratory disease and targeting its treatment in the future. Whether lung cytology findings coincide with clinical signs and lung ultrasonographic findings is currently unknown. Therefore, the objective of the present study was to determine the association of lung cytology with clinical signs, lung consolidation and broncho-alveolar lavage fluid (BALf) characteristics (including bacteriology). A total of 352 indoor group-housed calves aged between 1 and 6 months from 62 conveniently selected commercial herds were included in this cross-sectional study. Clinical examination, thoracic ultrasound and bacteriology and cytology on non-endoscopic broncho-alveolar lavage (nBAL) samples were performed. RESULTS: Pneumonia, defined as presence of ultrasonographic lung consolidations ≥1 cm in depth, affected 42.4% of the calves. Mean BALf neutrophil percentage was 36.6% (SD 23.8; R 0-97.4) and only a positive induced tracheal cough reflex (P = 0.04), standing posture (P = 0.03) increased breathing rate (P = 0.02) and isolation of Pasteurella multocida (P = 0.005), were associated with increased neutrophil percentage. No significant associations between lung ultrasonographic findings and cytology results were present, except for presence of basophils in BALf and consolidation of > 3 cm in depth (OR = 2.6; CI = 1.2-5.6; P = 0.01). Abnormal lung sounds were associated with detection of eosinophils in BALf (OR = 2.8; CI = 1.0-8.1; P = 0.05). Total nucleated cell count (TNCC) (P <  0.001) was positively and macrophage percentage (P = 0.02) negatively associated with volume of lavage fluid recovered. Macroscopic blood staining of BALf increased TNCC (P = 0.002) and lymphocyte percentage (P = 0.001). CONCLUSIONS: Only a limited number of clinical signs and ultrasonographic findings were associated with nBAL cytology. BALf cytology offers additional and distinct information in calves aiding in detection and prevention of respiratory conditions. In this population, selected from herds not reporting any recent respiratory illness, a high number of calves had ultrasonographic lung consolidation and high neutrophil percentage in BALf, suggesting that subclinical disease presentations frequently occur.


Assuntos
Líquido da Lavagem Broncoalveolar/citologia , Líquido da Lavagem Broncoalveolar/microbiologia , Pneumonia/veterinária , Animais , Bactérias/classificação , Bactérias/isolamento & purificação , Lavagem Broncoalveolar/métodos , Lavagem Broncoalveolar/veterinária , Bovinos , Estudos Transversais , Abrigo para Animais , Neutrófilos , Pasteurella multocida/isolamento & purificação , Pneumonia/diagnóstico por imagem , Pneumonia/microbiologia , Sons Respiratórios/veterinária , Tórax/diagnóstico por imagem , Ultrassonografia/veterinária
5.
Arch Toxicol ; 93(2): 293-310, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30535711

RESUMO

A clinical case in Belgium demonstrated that feeding a feed concentrate containing considerable levels of deoxynivalenol (DON, 1.13 mg/kg feed) induced severe liver failure in 2- to 3-month-old beef calves. Symptoms disappeared by replacing the highly contaminated corn and by stimulating ruminal development via roughage administration. A multi-mycotoxin contamination was demonstrated in feed samples collected at 15 different veal farms in Belgium. DON was most prevalent, contaminating 80% of the roughage samples (mixed straw and maize silage; average concentration in positives: 637 ± 621 µg/kg, max. 1818 µg/kg), and all feed concentrate samples (411 ± 156 µg/kg, max. 693 µg/kg). In order to evaluate the impact of roughage provision and its associated ruminal development on the gastro-intestinal absorption and biodegradation of DON and its acetylated derivatives (3- and 15-ADON) in calves, a toxicokinetic study was performed with two ruminating and two non-ruminating male calves. Animals received in succession a bolus of DON (120 µg/kg bodyweight (BW)), 15-ADON (50 µg/kg BW), and 3-ADON (25 µg/kg) by intravenous (IV) injection or per os (PO) in a cross-over design. The absolute oral bioavailability of DON was much higher in non-ruminating calves (50.7 ± 33.0%) compared to ruminating calves (4.1 ± 4.5%). Immediately following exposure, 3- and 15-ADON were hydrolysed to DON in ruminating calves. DON and its acetylated metabolites were mainly metabolized to DON-3-glucuronide, however, also small amounts of DON-15-glucuronide were detected in urine. DON degradation to deepoxy-DON (DOM-1) was only observed to a relevant extent in ruminating calves. Consequently, toxicity of DON in calves is closely related to roughage provision and the associated stage of ruminal development.


Assuntos
Ração Animal/análise , Fibras na Dieta/farmacologia , Falência Hepática/veterinária , Tricotecenos/farmacocinética , Tricotecenos/toxicidade , Acetilação , Ração Animal/toxicidade , Animais , Disponibilidade Biológica , Bovinos , Exposição Dietética/efeitos adversos , Exposição Dietética/análise , Fibras na Dieta/análise , Icterícia/induzido quimicamente , Icterícia/veterinária , Fígado/efeitos dos fármacos , Fígado/enzimologia , Fígado/patologia , Falência Hepática/induzido quimicamente , Falência Hepática/patologia , Masculino , Ruminação Digestiva , Tricotecenos/análise , Tricotecenos/intoxicação
6.
BMC Vet Res ; 14(1): 290, 2018 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-30249249

RESUMO

BACKGROUND: When surgical treatment of cervical vertebral malformation is considered, precise localization of compression sites is essential, but remains challenging. Magnetic motor evoked potentials (mMEP) from paravertebral muscles are useful in localizing spinal cord lesions, but no information about cervical muscle mMEP in horses is available yet. Therefore, the aim of this study was to determine the possibility, normal values, inter- and intra-observer agreement and factors that have an effect on cervical mMEP in healthy horses. METHODS: Transcranial magnetic stimulation was performed on 50 normal horses and 4 (2 left, 2 right) muscle responses were recorded at the middle of each cervical vertebra (C1-C7) and additionally just caudal to C7 to evaluate cervical nerves (Cn) Cn1 to Cn8. Latency time and amplitude of the recorded mMEP were defined by both an experienced and an unexperienced operator. RESULTS: Latency increased gradually from 14.2 ± 1.38 ms for Cn3 to 17.7 ± 1.36 ms for Cn8, was significantly influenced by cervical nerve (P < 0.01), gender (P = 0.02) and height (P = 0.03) and had a good intra-observer agreement. The smallest mean amplitude (4.35 ± 2.37 mV) was found at Cn2, the largest (5.99 ± 2.53 mV) at Cn3. Amplitude was only significantly influenced by cervical nerve (P < 0.01) and had a low intra-observer agreement. No significant effect of observer on latency (P = 0.88) or amplitude (P = 0.99) measurements was found. CONCLUSION: mMEP of cervical muscles in normal horses are easy to collect and to evaluate with limited intra- and inter-observer variation concerning amplitude and should be investigated in future studies in ataxic horses to evaluate its clinical value.


Assuntos
Vértebras Cervicais/anormalidades , Potencial Evocado Motor , Cavalos , Músculo Esquelético/inervação , Animais , Vértebras Cervicais/inervação , Feminino , Masculino , Músculo Esquelético/fisiologia , Doenças da Medula Espinal/diagnóstico , Doenças da Medula Espinal/veterinária
7.
Vet Res ; 48(1): 9, 2017 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-28209206

RESUMO

Bovine necro-haemorrhagic enteritis is an economically important disease caused by Clostridium perfringens type A strains. The disease mainly affects calves under intensive rearing conditions and is characterized by sudden death associated with small intestinal haemorrhage, necrosis and mucosal neutrophil infiltration. The common assumption that, when causing intestinal disease, C. perfringens relies upon specific, plasmid-encoded toxins, was recently challenged by the finding that alpha toxin, which is produced by all C. perfringens strains, is essential for necro-haemorrhagic enteritis. In addition to alpha toxin, other C. perfringens toxins and/or enzymes might contribute to the pathogenesis of necro-haemorrhagic enteritis. These additional virulence factors might contribute to breakdown of the protective mucus layer during initial stage of pathogenesis, after which alpha toxin, either or not in synergy with other toxins such as perfringolysin O, can act on the mucosal tissue. Furthermore, alpha toxin alone does not cause intestinal necrosis, indicating that other virulence factors might be needed to cause the extensive tissue necrosis observed in necro-haemorrhagic enteritis. This review summarizes recent research that has increased our understanding of the pathogenesis of bovine necro-haemorrhagic enteritis and provides information that is indispensable for the development of novel control strategies, including vaccines.


Assuntos
Proteínas de Ligação ao Cálcio/fisiologia , Doenças dos Bovinos/microbiologia , Clostridium perfringens , Enterite/veterinária , Gangrena Gasosa/veterinária , Fosfolipases Tipo C/fisiologia , Animais , Toxinas Bacterianas , Bovinos/microbiologia , Enterite/microbiologia , Gangrena Gasosa/microbiologia
8.
Vet Res ; 47(1): 52, 2016 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-27121298

RESUMO

Bovine necrohemorrhagic enteritis is caused by Clostridium perfringens and leads to sudden death. Alpha toxin, together with perfringolysin O, has been identified as the principal toxin involved in the pathogenesis. We assessed the potential of alpha toxin as a vaccine antigen. Using an intestinal loop model in calves, we investigated the protection afforded by antisera raised against native alpha toxin or its non-toxic C-terminal fragment against C. perfringens-induced intestinal necrosis. Immunization of calves with either of the vaccine preparations induced a strong antibody response. The resulting antisera were able to neutralize the alpha toxin activity and the C. perfringens-induced endothelial cytotoxicity in vitro. The antisera raised against the native toxin had a stronger neutralizing activity than those against the C-terminal fragment. However, antibodies against alpha toxin alone were not sufficient to completely neutralize the C. perfringens-induced necrosis in the intestinal loop model. The development of a multivalent vaccine combining the C-terminal fragment of alpha toxin with other C. perfringens virulence factors might be necessary for complete protection against bovine necrohemorrhagic enteritis.


Assuntos
Toxinas Bacterianas/uso terapêutico , Vacinas Bacterianas/uso terapêutico , Proteínas de Ligação ao Cálcio/uso terapêutico , Doenças dos Bovinos/prevenção & controle , Infecções por Clostridium/veterinária , Enterite/veterinária , Fosfolipases Tipo C/uso terapêutico , Animais , Animais Recém-Nascidos , Formação de Anticorpos/imunologia , Toxinas Bacterianas/imunologia , Vacinas Bacterianas/imunologia , Proteínas de Ligação ao Cálcio/imunologia , Bovinos , Doenças dos Bovinos/microbiologia , Infecções por Clostridium/prevenção & controle , Clostridium perfringens , Enterite/microbiologia , Enterite/prevenção & controle , Ensaio de Imunoadsorção Enzimática/veterinária , Intestinos/patologia , Masculino , Necrose , Proteínas Recombinantes , Fosfolipases Tipo C/imunologia
9.
BMC Vet Res ; 12(1): 101, 2016 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-27297520

RESUMO

BACKGROUND: Bovine necrohemorrhagic enteritis is caused by Clostridium perfringens type A. Due to the rapid progress and fatal outcome of the disease, vaccination would be of high value. In this study, C. perfringens toxins, either as native toxins or after formaldehyde inactivation, were evaluated as possible vaccine antigens. We determined whether antisera raised in calves against these toxins were able to protect against C. perfringens challenge in an intestinal loop model for bovine necrohemorrhagic enteritis. RESULTS: Alpha toxin and perfringolysin O were identified as the most immunogenic proteins in the vaccine preparations. All vaccines evoked a high antibody response against the causative toxins, alpha toxin and perfringolysin O, as detected by ELISA. All antibodies were able to inhibit the activity of alpha toxin and perfringolysin O in vitro. However, the antibodies raised against the native toxins were more inhibitory to the C. perfringens-induced cytotoxicity (as tested on bovine endothelial cells) and only these antibodies protected against C. perfringens challenge in the intestinal loop model. CONCLUSION: Although immunization of calves with both native and formaldehyde inactivated toxins resulted in high antibody titers against alpha toxin and perfringolysin O, only antibodies raised against native toxins protect against C. perfringens challenge in an intestinal loop model for bovine necrohemorrhagic enteritis.


Assuntos
Anticorpos Neutralizantes/imunologia , Toxinas Bacterianas/administração & dosagem , Vacinas Bacterianas/administração & dosagem , Proteínas de Ligação ao Cálcio/administração & dosagem , Doenças dos Bovinos/microbiologia , Infecções por Clostridium/veterinária , Clostridium perfringens/imunologia , Enterite/veterinária , Proteínas Hemolisinas/administração & dosagem , Fosfolipases Tipo C/administração & dosagem , Animais , Toxinas Bacterianas/imunologia , Toxinas Bacterianas/toxicidade , Vacinas Bacterianas/imunologia , Vacinas Bacterianas/toxicidade , Proteínas de Ligação ao Cálcio/imunologia , Proteínas de Ligação ao Cálcio/toxicidade , Bovinos , Doenças dos Bovinos/imunologia , Doenças dos Bovinos/prevenção & controle , Infecções por Clostridium/imunologia , Infecções por Clostridium/patologia , Infecções por Clostridium/prevenção & controle , Modelos Animais de Doenças , Células Endoteliais/imunologia , Enterite/imunologia , Enterite/patologia , Enterite/prevenção & controle , Proteínas Hemolisinas/imunologia , Proteínas Hemolisinas/toxicidade , Jejuno/imunologia , Masculino , Necrose , Fosfolipases Tipo C/imunologia , Fosfolipases Tipo C/toxicidade
10.
Can Vet J ; 56(2): 178-84, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25694668

RESUMO

This study compared serotonin concentrations in platelet poor plasma (PPP) from healthy horses and horses with surgical small intestinal (SI) colic, and evaluated their association with postoperative ileus, strangulation and non-survival. Plasma samples (with EDTA) from 33 horses with surgical SI colic were collected at several pre- and post-operative time points. Serotonin concentrations were determined using liquid-chromatography tandem mass spectrometry. Results were compared with those for 24 healthy control animals. The serotonin concentrations in PPP were significantly lower (P < 0.01) in pre- and post-operative samples from surgical SI colic horses compared to controls. However, no association with postoperative ileus or non-survival could be demonstrated at any time point. In this clinical study, plasma serotonin was not a suitable prognostic factor in horses with SI surgical colic.


Sérotonine plasmatique chez des chevaux subissant une chirurgie pour des coliques du petit intestin. Cette étude a comparé les concentrations de sérotonine dans le plasma faible en plaquettes (PFP) de chevaux en santé et de chevaux atteints de coliques chirurgicales du petit intestin et a évalué leur association avec l'occlusion intestinale postopératoire, la strangulation et la non-survie. Des échantillons de plasma (avec EDTA) ont été prélevés auprès de 33 chevaux atteints de coliques du petit intestin à plusieurs moments préopératoires et postopératoires. Les concentrations de sérotonine ont été déterminées à l'aide d'un spectromètre de masse LC-ESI-MS/MS. Les résultats ont été comparés avec ceux de 24 animaux témoins en santé. Les concentrations de sérotonine du PFP étaient significativement inférieures (P < 0,01) dans les échantillons préopératoires et postopératoires provenant des chevaux atteints de coliques du petit intestin comparativement aux animaux témoins. Cependant, aucune association avec l'occlusion intestinale postopératoire ou la non-survie n'a pu être démontrée à aucun moment. Dans cette étude clinique, la sérotonine plasmatique ne s'est pas avéré un facteur de pronostic approprié chez les chevaux atteints de coliques chirurgicales du petit intestin.(Traduit par Isabelle Vallières).


Assuntos
Cólica/veterinária , Doenças dos Cavalos/cirurgia , Intestino Delgado/patologia , Serotonina/sangue , Animais , Cólica/sangue , Cólica/patologia , Cólica/cirurgia , Feminino , Doenças dos Cavalos/sangue , Cavalos , Masculino , Ativação Plaquetária , Serotonina/metabolismo
11.
BMC Vet Res ; 10: 32, 2014 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-24479821

RESUMO

BACKGROUND: Bovine enterotoxemia is a major cause of mortality in veal calves. Predominantly veal calves of beef cattle breeds are affected and losses due to enterotoxemia may account for up to 20% of total mortality. Clostridium perfringens type A is considered to be the causative agent. Recently, alpha toxin and perfringolysin O have been proposed to play an essential role in the development of disease. However, other potential virulence factors also may play a role in the pathogenesis of bovine enterotoxemia. The aim of this study was to evaluate whether strains originating from bovine enterotoxemia cases were superior in in vitro production of virulence factors (alpha toxin, perfringolysin O, mucinase, collagenase) that are potentially involved in enterotoxemia. To approach this, a collection of strains originating from enterotoxemia cases was compared to bovine strains isolated from healthy animals and to strains isolated from other animal species. RESULTS: Strains originating from bovine enterotoxemia cases produced variable levels of alpha toxin and perfringolysin O that were not significantly different from levels produced by strains isolated from healthy calves and other animal species. All tested strains exhibited similar mucinolytic activity independent of the isolation source. A high variability in collagenase activity between strains could be observed, and no higher collagenase levels were produced in vitro by strains isolated from enterotoxemia cases. CONCLUSIONS: Bovine enterotoxemia strains do not produce higher levels of alpha toxin, perfringolysin O, mucinase and collagenase, as compared to strains derived from healthy calves and other animal species in vitro.


Assuntos
Toxinas Bacterianas/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Doenças dos Bovinos/microbiologia , Clostridium perfringens/classificação , Clostridium perfringens/metabolismo , Enterotoxemia/microbiologia , Proteínas Hemolisinas/metabolismo , Peptídeo Hidrolases/metabolismo , Fosfolipases Tipo C/metabolismo , Animais , Toxinas Bacterianas/genética , Proteínas de Ligação ao Cálcio/genética , Bovinos , Clostridium perfringens/genética , Regulação Bacteriana da Expressão Gênica/fisiologia , Regulação Enzimológica da Expressão Gênica/fisiologia , Proteínas Hemolisinas/genética , Peptídeo Hidrolases/genética , Fosfolipases Tipo C/genética
12.
Vet Res ; 44: 45, 2013 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-23782465

RESUMO

Bovine necrohemorrhagic enteritis is a major cause of mortality in veal calves. Clostridium perfringens is considered as the causative agent, but there has been controversy on the toxins responsible for the disease. Recently, it has been demonstrated that a variety of C. perfringens type A strains can induce necrohemorrhagic lesions in a calf intestinal loop assay. These results put forward alpha toxin and perfringolysin as potential causative toxins, since both are produced by all C. perfringens type A strains. The importance of perfringolysin in the pathogenesis of bovine necrohemorrhagic enteritis has not been studied before. Therefore, the objective of the current study was to evaluate the role of perfringolysin in the development of necrohemorrhagic enteritis lesions in calves and its synergism with alpha toxin. A perfringolysin-deficient mutant, an alpha toxin-deficient mutant and a perfringolysin alpha toxin double mutant were less able to induce necrosis in a calf intestinal loop assay as compared to the wild-type strain. Only complementation with both toxins could restore the activity to that of the wild-type. In addition, perfringolysin and alpha toxin had a synergistic cytotoxic effect on bovine endothelial cells. This endothelial cell damage potentially explains why capillary hemorrhages are an initial step in the development of bovine necrohemorrhagic enteritis. Taken together, our results show that perfringolysin acts synergistically with alpha toxin in the development of necrohemorrhagic enteritis in a calf intestinal loop model and we hypothesize that both toxins act by targeting the endothelial cells.


Assuntos
Toxinas Bacterianas/toxicidade , Proteínas de Ligação ao Cálcio/toxicidade , Doenças dos Bovinos/microbiologia , Clostridium perfringens/fisiologia , Enterite/veterinária , Proteínas Hemolisinas/toxicidade , Fosfolipases Tipo C/toxicidade , Animais , Toxinas Bacterianas/genética , Toxinas Bacterianas/metabolismo , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Bovinos , Clostridium perfringens/genética , Células Endoteliais/microbiologia , Células Endoteliais/patologia , Enterite/microbiologia , Ensaio de Imunoadsorção Enzimática/veterinária , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/metabolismo , Intestinos/microbiologia , Intestinos/patologia , Mutação , Necrose/microbiologia , Necrose/veterinária , Fosfolipases Tipo C/genética , Fosfolipases Tipo C/metabolismo
13.
BMC Vet Res ; 9: 79, 2013 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-23587206

RESUMO

BACKGROUND: Little is known on the effects of common calf diseases on mortality and carcass traits in the white veal industry (special-fed veal), a highly integrated production system, currently criticized for the intensive pro- and metaphylactic use of antimicrobials. The objective of the present study was to determine the impact of bovine respiratory disease (BRD), diarrhea, arthritis and otitis on the economically important parameters of mortality, hot carcass weight (HCW), carcass quality, fat cover and meat color. For this purpose, a prospective study on 3519 white veal calves, housed in 10 commercial herds, was conducted. Case definitions were based on clinical observation by the producers and written treatment records were used. RESULTS: Calves received oral antimicrobial group treatments in the milk during 25.2% of the production time on average. With an increasing percentage of the production cycle spent on oral antimicrobials, HCW reduced, whereas the odds for insufficient fat cover or an undesirable red meat color both decreased. Of the calves, 14.8%, 5.3%, 1.5% and 1.6% were individually diagnosed and treated for BRD, diarrhea, arthritis and otitis, respectively. Overall, 5.7% of the calves died and the mortality risk was higher in the first weeks after arrival. Calves that experienced one BRD episode showed a 8.2 kg reduction in HCW, a lower fat cover and an increased mortality risk (hazard ratio (HR) = 5.5), compared to calves which were not individually diagnosed and treated for BRD. With an increasing number of BRD episodes, these losses increased dramatically. Additionally, calves, which experienced multiple BRD episodes, were more likely to have poor carcass quality and an undesirable red meat color at slaughter. Arthritis increased the mortality risk (HR = 3.9), and reduced HCW only when associated with BRD. Otitis did only increase the mortality risk (HR = 7.0). Diarrhea severely increased the mortality risk (HR = 11.0), reduced HCW by 9.2 kg on average and decreased carcass quality. CONCLUSIONS: Despite the massive use of group and individual treatments to alleviate the most prevalent health issues at the fattening period, the effects of BRD, diarrhea, otitis and arthritis on survival and performance are still considerable, especially in cases of chronic pneumonia with or without arthritis. Controlling calf health by effective preventive and therapeutic strategies and in particular the prevention of chronic BRD is key for the profitability of veal operations.


Assuntos
Artrite/veterinária , Doenças dos Bovinos/epidemiologia , Diarreia/veterinária , Carne/economia , Otite/veterinária , Doenças Respiratórias/veterinária , Criação de Animais Domésticos/economia , Criação de Animais Domésticos/métodos , Animais , Antibacterianos/economia , Antibacterianos/uso terapêutico , Artrite/economia , Artrite/epidemiologia , Bélgica , Bovinos , Doenças dos Bovinos/economia , Estudos de Coortes , Diarreia/economia , Diarreia/epidemiologia , Feminino , Estimativa de Kaplan-Meier , Masculino , Otite/economia , Otite/epidemiologia , Prevalência , Modelos de Riscos Proporcionais , Estudos Prospectivos , Doenças Respiratórias/economia , Doenças Respiratórias/epidemiologia
14.
J Antimicrob Chemother ; 67(4): 1027-38, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22262796

RESUMO

OBJECTIVES: To document and quantify drug use in white veal calves, an intensive livestock production system where multidrug resistance is abundantly present. METHODS: Drug consumption data were prospectively collected on 15 white veal production cohorts (n = 5853 calves) in Belgium (2007-09). Treatment incidences (TIs) based on animal defined daily dose (ADD), prescribed daily dose (PDD) and used daily dose (UDD) were calculated. Risk factors were identified by linear regression. RESULTS: The average TI(ADD) of antimicrobial treatments was 416.8 ADD per 1000 animals at risk. Predominantly, oral group antimicrobial treatments were used (95.8%). Of the oral group antimicrobial treatments, 12% and 88% were used for prophylactic or metaphylactic indications, respectively. The main indication for group and individual drug use was respiratory disease. The most frequently used antimicrobials (group treatments) were oxytetracycline (23.7%), amoxicillin (18.5%), tylosin (17.2%) and colistin (15.2%). Deviations from the leaflet dosage recommendations were frequently encountered, with 43.7% of the group treatments underdosed (often oxytetracycline and tylosin to treat dysbacteriosis). In 33.3% of the oral antimicrobial group treatments a combination of two antimicrobial preparations was used. Smaller integrations used more antimicrobials in group treatments than larger ones (P < 0.05); an integration is defined as a company that combines all steps of the production chain by having its own feed plant and slaughterhouse and by placing its calves in veal herds owned by producers that fatten these calves for this integration on contract. Producers used higher dosages than prescribed by the veterinarian in cohorts with a single caretaker (P < 0.01). CONCLUSIONS: The present study provided detailed information on the intensive antimicrobial use in the white veal industry. Reduction can only be achieved by reducing the number of oral group treatments.


Assuntos
Antibacterianos/uso terapêutico , Anti-Inflamatórios/uso terapêutico , Doenças dos Bovinos/tratamento farmacológico , Uso de Medicamentos/estatística & dados numéricos , Animais , Bélgica , Bovinos , Estudos Prospectivos
15.
Appl Environ Microbiol ; 78(24): 8515-22, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23001653

RESUMO

Clostridium difficile strains were sampled periodically from 50 animals at a single veal calf farm over a period of 6 months. At arrival, 10% of animals were C. difficile positive, and the peak incidence was determined to occur at the age of 18 days (16%). The prevalence then decreased, and at slaughter, C. difficile could not be isolated. Six different PCR ribotypes were detected, and strains within a single PCR ribotype could be differentiated further by pulsed-field gel electrophoresis (PFGE). The PCR ribotype diversity was high up to the animal age of 18 days, but at later sampling points, PCR ribotype 078 and the highly related PCR ribotype 126 predominated. Resistance to tetracycline, doxycycline, and erythromycin was detected, while all strains were susceptible to amoxicillin and metronidazole. Multiple variations of the resistance gene tet(M) were present at the same sampling point, and these changed over time. We have shown that PCR ribotypes often associated with cattle (ribotypes 078, 126, and 033) were not clonal but differed in PFGE type, sporulation properties, antibiotic sensitivities, and tetracycline resistance determinants, suggesting that multiple strains of the same PCR ribotype infected the calves and that calves were likely to be infected prior to arrival at the farm. Importantly, strains isolated at later time points were more likely to be resistant to tetracycline and erythromycin and showed higher early sporulation efficiencies in vitro, suggesting that these two properties converge to promote the persistence of C. difficile in the environment or in hosts.


Assuntos
Clostridioides difficile/efeitos dos fármacos , Clostridioides difficile/crescimento & desenvolvimento , Farmacorresistência Bacteriana , Ribotipagem , Esporos Bacterianos/crescimento & desenvolvimento , Animais , Antibacterianos/farmacologia , Bovinos , Clostridioides difficile/classificação , Clostridioides difficile/genética , DNA Bacteriano/química , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado , Fezes/microbiologia , Variação Genética , Genótipo , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Análise de Sequência de DNA
16.
BMC Vet Res ; 8: 26, 2012 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-22414223

RESUMO

BACKGROUND: Mortality and morbidity are hardly documented in the white veal industry, despite high levels of antimicrobial drug use and resistance. The objective of the present study was to determine the causes and epidemiology of morbidity and mortality in dairy, beef and crossbred white veal production. A total of 5853 calves, housed in 15 production cohorts, were followed during one production cycle. Causes of mortality were determined by necropsy. Morbidity was daily recorded by the producers. RESULTS: The total mortality risk was 5,3% and was significantly higher in beef veal production compared to dairy or crossbreds. The main causes of mortality were pneumonia (1.3% of the calves at risk), ruminal disorders (0.7%), idiopathic peritonitis (0.5%), enterotoxaemia (0.5%) and enteritis (0.4%). Belgian Blue beef calves were more likely to die from pneumonia, enterotoxaemia and arthritis. Detection of bovine viral diarrhea virus at necropsy was associated with chronic pneumonia and pleuritis. Of the calves, 25.4% was treated individually and the morbidity rate was 1.66 cases per 1000 calf days at risk. The incidence rate of respiratory disease, diarrhea, arthritis and otitis was 0.95, 0.30, 0.11 and 0.07 cases per 1000 calf days at risk respectively. Morbidity peaked in the first three weeks after arrival and gradually declined towards the end of the production cycle. CONCLUSIONS: The present study provided insights into the causes and epidemiology of morbidity and mortality in white veal calves in Belgium, housed in the most frequent housing system in Europe. The necropsy findings, identified risk periods and differences between production systems can guide both veterinarians and producers towards the most profitable and ethical preventive and therapeutic protocols.


Assuntos
Doenças dos Bovinos/mortalidade , Criação de Animais Domésticos , Animais , Bélgica/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Estudos de Coortes , Feminino , Incidência , Estudos Longitudinais , Masculino , Morbidade , Análise Multivariada , Modelos de Riscos Proporcionais , Estudos Prospectivos
17.
Can Vet J ; 52(10): 1135-9, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22467972

RESUMO

After 3 cows of a dairy herd had died from severe hemorrhagic diarrhea, a 4th sick cow was transported to the clinic. Blood analyses revealed the complete absence of white blood cells, the presence of a type 1b strain of bovine viral diarrhea virus (BVDV), and seroconversion to BVDV.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/diagnóstico , Vírus da Diarreia Viral Bovina Tipo 1 , Proctocolite/veterinária , Animais , Doença das Mucosas por Vírus da Diarreia Viral Bovina/virologia , Bovinos , Evolução Fatal , Feminino , Gravidez , Proctocolite/diagnóstico , Proctocolite/virologia
18.
Prev Vet Med ; 187: 105251, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33418516

RESUMO

Male dairy calves are exposed to an accumulation of transport, social and environmental stressors while transferred to fattening units. As a consequence, calves show high cortisol concentrations upon arrival at the veal facility. Whether cortisol levels as measured on arrival can be associated with animal health, welfare and production results is currently unknown. The first objective of this prospective cohort study was to determine possible associations of arrival serum cortisol concentration with health and production variables of veal calves and other arrival predictors like body weight and γ-globulin concentration. The second aim was to investigate potential clustering of arrival risk factors in veal calves for developing bovine respiratory disease (BRD) based on arrival body weight, serum cortisol concentration, total protein and protein fractions. In total, 105 male Holstein calves from two consecutive production cycles in a single, commercial white veal farm were blood sampled directly at arrival on the farm to determine serum cortisol, total protein and protein fractions. All calves were weighed the day after arrival and clinical signs, average daily weight gain (ADG) and carcass weight were collected. Also, all calves of both production cohorts were repeatedly examined by thoracic ultrasonography at the onset of group respiratory disease symptoms (2-3 weeks after arrival) and four weeks later. Linear and logistic mixed models together with k-means clustering were used for statistical analyses. Calves showed on average high, but individually variable serum cortisol concentrations (mean value = 96.6 ng/mL ± standard deviation (SD) = 48.8; Range (R) = 50.0-317 ng/mL). Arrival cortisol, body weight and γ-globulin content were not significantly associated. Serum cortisol and albumin concentrations at arrival were associated with chronic, unresponsive pneumonia. For each increase of serum cortisol concentration by 10 ng/mL, the odds for lung consolidation of ≥1 cm in depth at the second ultrasonography increased, odds ratio (OR) = 1.03 (95 % confidence interval (CI) = 1.01-1.06; P < 0.050). For every decrease in serum albumin concentration by 1g/L, the OR for developing pneumonia was 1.23 (95 % CI= 1.04-1.46; P < 0.015). Additionally, two clusters of calves were identified based upon arrival status: a low risk cluster with below average stress-induced cortisol values, above average body weight, no acute phase response (APR) and no failure of passive immune transfer (FPIT), and a high risk cluster with above average cortisol values, below average body weight, APR and FPIT. High risk calves had higher odds for developing clinical BRD (OR= 3.88 (95 % CI=1.20-12.53; P < 0.020)) and lung consolidation ≥1 cm in depth at week 6-7 after arrival (OR= 3.93 (95 % CI=1.34-11.53; P < 0.013)). Avoiding high cortisol levels upon arrival of calves is important for animal welfare, but also for reduction of the prevalence of chronic, unresponsive pneumonia and the associated need for (repeated) antimicrobial treatment and production losses.


Assuntos
Proteínas Sanguíneas/metabolismo , Complexo Respiratório Bovino/epidemiologia , Hidrocortisona/sangue , Animais , Peso Corporal , Bovinos/fisiologia , Masculino , Estudos Prospectivos , Fatores de Risco
19.
Res Vet Sci ; 130: 139-143, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32182439

RESUMO

MALDI-TOF MS is a fast and accurate tool to identify Mycoplasma species in liquid media. However, when trying to identify presumptive Mycoplasma bovis (M. bovis) colonies from solid medium (the "direct transfer method") a surprisingly high occurrence of M. arginini and M. alkalescens identification was observed. It was hypothesized that agar medium components are associated with false positive identification with Mycoplasma spp., as M. bovis colonies are very small and grow into the agar. The objective of this study was to determine whether complete modified pleuropneumonia-like organism (PPLO) agar (supplemented with horse serum, sodium pyruvate, technical yeast extract, ampicillin sodium salt and colistin) and the separate components, result in false identification as Mycoplasma spp. by MALDI-TOF MS. A total of 100 samples were examined, of which 33% of the modified PPLO agar spots were identified as M. alkalescens (16%) and M. arginini (17%)), albeit with relatively low score values (< 1.85). No false identification of M. bovis was obtained. Several medium components (unsupplemented PPLO agar, horse serum and colistin) resulted in spectra with peaks showing close matches with peaks present in the M. alkalescens and M. arginini database spectra. This study shows that the direct transfer method should be interpreted with caution, and one should strive to pick as little as possible agar when sampling Mycoplasma-like colonies from solid medium containing PPLO agar, horse serum and/or colistin.


Assuntos
Ágar/química , Doenças dos Bovinos/diagnóstico , Meios de Cultura/química , Infecções por Mycoplasma/veterinária , Mycoplasma/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/veterinária , Animais , Bovinos , Doenças dos Bovinos/microbiologia , Testes Diagnósticos de Rotina/veterinária , Infecções por Mycoplasma/diagnóstico , Infecções por Mycoplasma/microbiologia , Manejo de Espécimes/veterinária
20.
Prev Vet Med ; 179: 104979, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32388034

RESUMO

Under the present intensive rearing conditions, calves face a series of stressors and multiple pathogens often necessitating antimicrobial use. Multiple feed additives are currently explored for their ability to prevent disease and limit the use of antimicrobials. Supplementation of the polyunsaturated long chain n-3 fatty acids eicosapentaenoic (EPA) and docohexaenoic (DHA) from marine origin has been proposed as a strategy to improve immune function and prevent excessive inflammation reactions. The aim of this randomized clinical trial was to explore the effects of n-3 fatty acids (PUFAs) used as feed supplement on health, production and immune variables in a veal calf setting. One hundred-seventy calves were randomly assigned to 3 treatment groups: microalgae (MA, n = 57, 2.5 g DHA/animal/day), fish oil (FO, n = 57, 2.5 g EPA + DHA/animal/day)] and a control group (CON, n = 56). Average daily gain (ADG), bodyweight at 12 weeks on feed and slaughter weight were determined. Health monitoring consisted of recording of clinical signs and repeated thoracic ultrasonography. After 5, 8 and 11 weeks of supplementation, the function of neutrophils, monocytes and peripheral blood mononuclear cells (PBMCs) was evaluated ex vivo by measuring reactive oxygen species (ROS) production by neutrophils and monocytes and proliferation of and cytokine release by PBMCs. Under the field conditions of this study, dietary supplementation of MA and FO showed very limited immunomodulatory effects. Feeding MA led to increased ROS production by neutrophils, Estimate (E) = 0.38, Standard Error (SE) = 0.14; P < 0.05, compared to the control calves after 5 weeks of in-feed supplementation. FO reduced IL-6 secretion E= -0.29, SE= 0.11; P < 0.05 compared to MA treated animals after 11 weeks on feed. Health and production variables were unaffected by treatments. The doses of EPA and DHA used in this study did not cause immunomodulatory changes in highly stressed calves to such an extent that this led to better health or growth of animals.


Assuntos
Bovinos/fisiologia , Ácidos Graxos Ômega-3/metabolismo , Imunidade Inata , Ração Animal/análise , Animais , Bovinos/crescimento & desenvolvimento , Bovinos/imunologia , Dieta/veterinária , Suplementos Nutricionais/análise , Ácido Eicosapentaenoico/administração & dosagem , Ácido Eicosapentaenoico/metabolismo , Ácidos Graxos Ômega-3/administração & dosagem , Imunidade Inata/efeitos dos fármacos , Masculino , Distribuição Aleatória
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