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In practice, veterinary surgeons frequently rely on lung auscultation as a confirmation test for pneumonia. To what extent diagnostic accuracy of lung auscultation varies between different practitioners is currently unknown. In this diagnostic test study, 49 Dutch veterinarians each auscultated between 8 and 10 calves, and communicated whether they would decide to treat the animal with antimicrobials or not. They were not allowed to perform any other aspect of the clinical examination. Their decisions were compared with lung ultrasonography findings. The average sensitivity and specificity of lung auscultation were 0.63 (sd=0.2; range=0.2–1.0) and 0.46 (sd=0.3; range=0.0–1.0), respectively. Of the participants, 8.2 per cent were 100 per cent sensitive, 16.3 per cent were 100 per cent specific, and only 4.0 per cent were perfect. The Krippendorff’s alpha was 0.18 (95 per cent confidence interval: −0.01 to 0.38), signifying poor reliability between multiple raters. Regardless of the poor diagnostic accuracy in this study, especially the large variation in a confirmation test between different practitioners could potentially cause professional damage as well as misuse of antimicrobials. This study could be seen as a gentle stimulus to regularly evaluate one’s diagnostic skills. Both complementary training and the use of more accurate techniques with less inter-rater variation could improve the situation.

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.

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.

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, bla , 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.

Background Whether underweight calves respond differently to transport stress, enhancing their disease risk, is currently unknown. Objective To determine the effects of low body weight and transport stress on immune variables. Animals Twenty‐one 2‐ to 4‐week‐old male Holstein calves, housed on a commercial farm. Methods Randomized clinical trial. Full factorial design with 4 treatment groups: low body weight (≤46 kg)/no transport (LOWCON); low body weight/transport (LOWTRANS); normal body weight (>46 kg)/no transport (NORMCON), and normal body weight/transport (NORMTRANS). Transport duration was 2 hours. Results Transport significantly increased serum cortisol concentration (77.8 μg/mL; 95% confidence interval [CI], 37.8‐131.6; P < .001), interleukin (IL)‐17A (344.9 pg/mL; 95% CI, 32.2‐556.5; P = .04), and tumor necrosis factor‐α (TNF‐α) (218.2 pg/mL; 95% CI, 32.5‐368.3; P = .03) production after lipopolysaccharide (LPS) stimulation. Body weight did not affect any of the studied variables. However, the interaction of transport and body weight was significant. LOWTRANS calves showed increased monocyte count (2.0 × 109/L; 95% CI, 0.6‐4.2; P < .05) and interleukin IL‐17A production (106.0 pg/mL; 95% CI, 4.2‐306.9; P = .03) compared to normal weight calves and increased TNF‐α production (275.6 pg/mL; 95% CI, 2.6‐463.0; P = .02) compared to LOWCON calves in unstimulated peripheral blood mononuclear cells (PBMCs) after transport. Conclusion and Clinical Importance These findings contribute to our understanding of increased disease susceptibility of underweight calves when transported. Gamma globulin concentration was identified as important interfering factor in studies on immune variables in neonatal calves.

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.

Background Transcranial magnetic stimulation (TMS) and recording of magnetic motor evoked potentials (MMEP) can detect neurological dysfunction in horses but cutoff values based on confirmed spinal cord dysfunction are lacking. Objectives To determine latency time cutoff for neurological dysfunction. Animals Five control horses and 17 horses with proprioceptive ataxia. Methods Case‐control study with receiver operating characteristic curve analysis, based on diagnostic imaging, TMS, and histopathological findings. Horses were included if all 3 examinations were performed. Results Diagnostic imaging and histopathology did not show abnormalities in the control group but confirmed spinal cord compression in 14 of 17 ataxic horses. In the remaining 3 horses, histopathological lesions were mild to severe, but diagnostic imaging did not confirm spinal cord compression. In control horses, latency time values of thoracic and pelvic limbs were significantly lower than in ataxic horses (20 ± 1 vs 34 ± 16 milliseconds, P = .05; and 39 ± 1 vs 78 ± 26 milliseconds, P = .004). Optimal cutoff values to detect spinal cord dysfunction were 22 milliseconds (sensitivity [95% CI interval], 88% [73%‐100%]; specificity, 100% [100%‐100%]) in thoracic and 40 milliseconds (sensitivity, 94% [83%‐100%]; specificity, 100% [100%‐100%]) in pelvic limbs. To detect spinal cord dysfunction caused by compression, the optimal cutoff for thoracic limbs remained 22 milliseconds, while it increased to 43 milliseconds in pelvic limbs (sensitivity, 100% [100%‐100%]; specificity, 100% [100%‐100%] for thoracic and pelvic limbs). Conclusions and Clinical Importance Magnetic motor evoked potential analysis using these cutoff values is a promising diagnostic tool for spinal cord dysfunction diagnosis in horses.

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.

Background Based on its pharmacokinetic profile and electrophysiological effects in healthy horses, sotalol potentially could be used as a long‐term PO antiarrhythmic drug in horses. Objectives To evaluate the effect of sotalol on heart rate (HR), QT interval, atrial fibrillatory rate, and success of cardioversion in horses with naturally occurring chronic atrial fibrillation (AF). Animals Twenty‐eight horses referred for transvenous electrical cardioversion of AF were treated with 2 mg/kg sotalol PO q12h for 3 days before cardioversion, and 13 horses underwent the same protocol without sotalol administration. Methods Retrospective study. Before and after sotalol or no treatment, the HR was measured at rest and during an exercise test. The QT interval and atrial fibrillation cycle length (AFCL) were measured at rest using tissue Doppler velocity imaging. Results In the control group, no significant differences were found between the 2 examinations. In the sotalol group, the HR at rest and during exercise was significantly lower after sotalol treatment, whereas the QT interval and AFCL measured by tissue Doppler increased significantly. Cardioversion to sinus rhythm was achieved in 25/28 horses in the sotalol group and all horses in the control group, but the median number of shocks and energy at cardioversion were significantly lower in the sotalol group. Conclusions and Clinical Importance In horses with AF, sotalol administration results in class III antiarrhythmic effects and β‐blocking activity, with moderate HR reduction during exercise.

Background Spinal cord dysfunction/compression and ataxia are common in horses. Presumptive diagnosis is most commonly based on neurological examination and cervical radiography, but the interest into the diagnostic value of transcranial magnetic stimulation (TMS) with recording of magnetic motor evoked potentials has increased. The problem for the evaluation of diagnostic tests for spinal cord dysfunction is the absence of a gold standard in the living animal. Objectives To compare diagnostic accuracy of TMS, cervical radiography, and neurological examination. Animals One hundred seventy‐four horses admitted at the clinic for neurological examination. Methods Retrospective comparison of neurological examination, cervical radiography, and different TMS criteria, using Bayesian latent class modeling to account for the absence of a gold standard. Results The Bayesian estimate of the prevalence (95% CI) of spinal cord dysfunction was 58.1 (48.3%‐68.3%). Sensitivity and specificity of neurological examination were 97.6 (91.4%‐99.9%) and 74.7 (61.0%‐96.3%), for radiography they were 43.0 (32.3%‐54.6%) and 77.3 (67.1%‐86.1%), respectively. Transcranial magnetic stimulation reached a sensitivity and specificity of 87.5 (68.2%‐99.2%) and 97.4 (90.4%‐99.9%). For TMS, the highest accuracy was obtained using the minimum latency time for the pelvic limbs (Youden's index = 0.85). In all evaluated models, cervical radiography performed poorest. Clinical Relevance Transcranial magnetic stimulation‐magnetic motor evoked potential (TMS‐MMEP) was the best test to diagnose spinal cord disease, the neurological examination was the second best, but the accuracy of cervical radiography was low. Selecting animals based on neurological examination (highest sensitivity) and confirming disease by TMS‐MMEP (highest specificity) would currently be the optimal diagnostic strategy.