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Bovine respiratory disease (BRD) continues to be a leading cause of economic loss, hampered animal welfare, and intensive antimicrobial use in cattle operations worldwide. Reduction of antimicrobial use is hindered because it is still unclear which clinical signs are best monitored to reliably detect pneumonia. Also, these clinical signs may vary according to age and between breeds. The objective of this cross-sectional study was to identify clinical signs associated with ultrasound-confirmed pneumonia (lung consolidation ≥1 cm depth) pre- and postweaning in different production types (dairy, beef, and veal) and breeds. A total of 956 calves (70% Holstein-Friesian dairy and 30% Belgian Blue beef) from 84 herds were clinically examined using 24 parameters, scored using the Wisconsin and California BRD clinical scoring systems and subjected to thoracic ultrasonography. Of the calves, 42.8% and 19.5% had a lung consolidation ≥1 cm and ≥3 cm, respectively. Cough, both spontaneous and induced, was the only and best-performing clinical sign statistically associated with lung consolidation in all production types. Fever (rectal temperature ≥39.4°C) was the second most promising factor, being significant in beef and veal calves but not in dairy calves. Postweaning, none of the clinical signs studied were statistically associated with pneumonia, with the exception of cough in dairy calves. Spontaneous or induced cough as a single clinical sign outperformed any combination of clinical signs, including the Wisconsin and California respiratory disease scoring systems, but sensitivity remained low. This information can be useful to select appropriate clinical signs for continuous monitoring in precision livestock applications, targeted to a given breed and age. As a cross-sectional measurement, diagnostic accuracy of spontaneous cough (accuracy = 65.1%, sensitivity = 37.4%, specificity = 85.7%) is too low to be used as a criterion to select animals with pneumonia for antimicrobial treatment. At the group level, cough monitoring holds potential as an early warning sign, after which lung ultrasonography should follow.

Quick thoracic ultrasonography (qTUS) is increas-ingly used as an on-farm method to diagnose clinical and subclinical pneumonia in dairy calves. The primary objective of this prospective cohort study was to de-scribe dynamics of lung consolidation in a purchase-dependent production system for male dairy calves in relation to antimicrobial therapy and respiratory diag-nostics. In addition, we studied the association of cured and uncured pneumonia with average daily gain (ADG) and cold carcass weight (CCW). The third objective was to determine the effects of arriving with lung consolidation on the probability of developing chronic unresponsive pneumonia and reduced performance. A total of 295 male dairy calves were intensively followed by qTUS and clinical scoring on 7 strategic occasions (wk 1, 2, 3, 4, 6, 8, and 12) during the production cycle. Of the calves, 17.6% (52/295) arrived with a lung con-solidation >1 cm. At the first outbreak of respiratory disease (wk 1 after arrival), this incidence had risen to 30.8%. Initial therapy with tulathromycin and subse-quently doxycycline appeared ineffective, resulting in a increase to 43.8% of calves having pneumonia in wk 4. At the start of the first outbreak (wk 1), the majority (86.8%) of the pneumonia cases were subclinical. At wk 4, the outbreak became more clinical, and treatment with amoxicillin resulted in a cure risk of 52.7%. Cul-ture and nanopore sequencing diagnostics on nonendo-scopic broncho-alveolar lavage (nBAL) samples identi-fied bovine respiratory syncytial virus and Mycoplasma bovis as the dominant agents in the first outbreak. The isolated M. bovis strain showed mutations associated with macrolide resistance. The second outbreak was characterized by a Pasteurella multocida superinfection and isolation of multiple M. bovis strains from nBAL diagnostic testing. Evaluated over the complete obser-vation period, 83.4% of the calves developed consolida-tions >1 cm on qTUS. Of these calves, 53.9% (135/246) were cured by antimicrobial therapy. Chronic pneumo-nia (>30 subsequent days of pneumonia) was seen in 13.9% of the animals (n = 41). Calves with uncured or chronic pneumonia had a lower ADG (992 +/- 174 g/d and 930 +/- 146 g/d, respectively) compared with calves that never developed pneumonia (ADG = 1,103 +/- 156 g/d). In contrast, calves that did fully cure trended toward a lower ADG than calves that never developed pneumonia, but differences were no longer significant. Also, the effect of uncured pneumonia was no longer significant for CCW. Calves with lung consolidation upon arrival had a lower ADG (981 +/- 159 g/d vs. 1,045 +/- 159 g/d) and were more likely to develop chronic pneumonia [odds ratio = 4.2; 95% confidence interval = 2.1-8.6] compared with calves without consolida-tion upon arrival. Animals with chronic pneumonia, in turn, had a lower CCW than animals without chronic pneumonia (10.3 +/- 4.4 kg; 95% confidence interval: 1.6-19.1 kg). This study documents the consequences of subclinical pneumonia upon arrival and pneumonia developed later in the production cycle on production outcomes in a veal calf setting. Both qTUS and nBAL diagnostics provide important information, offering potential for better control and prevention of bovine respiratory disease in dairy calves.

Background Respiratory infections are the main indication for antimicrobial use in calves. Optimal treatment duration currently is unknown, but shorter duration would likely decrease selection for antimicrobial resistance. Hypothesis/Objectives Determine differences in cure rate and healing time between animals treated with florfenicol and oxytetracycline in a natural outbreak of respiratory disease using reaeration observed on thoracic ultrasound examination as healing criterion. Animals Commercial farm housing 130, 3 to 9 month old Belgian blue beef calves. Methods Randomized clinical trial during an outbreak of respiratory disease. Metaphylactic treatment was initiated, randomly treating animals with either florfenicol or oxytetracycline. Ultrasonographic follow-up was done the first day and every other day for a 14-day period. At the individual animal level, treatment was discontinued when reaeration of the lungs occurred. Differences in cure rate and healing time were determined. Results Of the 130 animals studied, 67.7% developed a lung consolidation >= 0.5 cm. The mean ultrasonographic healing time was 2.5 days in the florfenicol group compared to 3.1 days in the oxytetracycline group (P = .04). After single treatment, 80.6% and 60.3% had no consolidations in the florfenicol and oxytetracycline groups, respectively (P = .01). A Mycoplasma bovis strain was genetically and phenotypically determined to be susceptible to both antimicrobials. Conclusions and Clinical Importance Ultrasonographic lung reaeration shows potential as a cure criterion to rationalize antimicrobial use for outbreaks of pneumonia. In our study, florfenicol resulted in a faster cure and higher reduction in antimicrobial usage than did oxytetracycline.

Agricultural operations are important sources of organic dust containing particulate matter (PM) and endotoxins, which have possible negative health con-sequences for both humans and animals. Dust concen-trations and composition in calf barns, as well as the potential health effects for these animals, are scarcely documented. The objective of this study was to mea-sure PM fractions and endotoxin concentrations in calf barns and study their associations with lung consoli-dation, respiratory tract inflammation, and infection in group-housed calves. In this cross-sectional study, samples from 24 dairy farms and 23 beef farms were collected in Belgium from January to April 2017. PM1.0, PM2.5 and PM10 (defined as particulate matter passing through a size-selective inlet with a 50% efficiency cut-off at a 1.0-μm, 2.5-μm, and 10-μm aerodynamic diam-eter, respectively) were sampled during a 24-h period using a Grimm aerosol spectrometer (Grimm Aerosol Technik Ainring GmbH & Co. KG). Endotoxin concen-tration was measured in the PM10 fraction. Thoracic ultrasonography was performed and broncho-alveolar lavage fluid was collected for cytology and bacteriology. Average PM concentrations were 16.3 μg/m3 (standard deviation, SD: 17.1; range: 0.20–771), 25.0 μg/m3 (SD: 25.3; range: 0.50–144.9), and 70.3 μg/m3 (SD: 54.5; range: 1.6–251.2) for PM1.0, PM2.5, and PM10, respec-tively. Mean endotoxin in the PM10 fraction was 4.2 endotoxin units (EU)/μg (SD: 5.50; range: 0.03–30.3). Concentrations in air were 205.7 EU/m3 (SD: 197.5; range: 2.32–901.0). Lung consolidations with a depth of ≥1, ≥3, and ≥6 cm were present in 43.1% (146/339), 27.4% (93/339), and 15.3% (52/339) of the calves, re-spectively. Exposure to fine (PM1.0) PM fractions was associated with increased odds of lung consolidations of ≥1 cm (odds ratio, OR: 3.3; confidence interval (CI): 1.5–7.1), ≥3 cm (OR: 2.8; CI: 1.2–7.1), and ≥6 cm (OR: 12.3; CI: 1.2–125.0). The odds of having lung consolidations of ≥1 cm (OR: 13.9; CI: 3.4–58.8) and ≥3 cm (OR: 6.7; 1.7–27.0) were higher when endotoxin concentrations in the dust mass exceeded 8.5 EU/μg. Broncho-alveolar lavage fluid neutrophil percentage was positively associated with PM10 concentration, and epithelial cell percentage was negatively associated with this fraction. Concentration of PM2.5 was positively as-sociated with epithelial cell percentage and isolation of Pasteurella multocida. Although concentrations of fine dust are lower in calf barns than in poultry and pig housings, in this study they were associated with pneumonia in calves. Dust control strategies for reduc-ing fine dust fractions in calf barns may benefit human and animal respiratory health

In this opinion, the antimicrobial resistant bacteria responsible for transmissible diseases that constitute a threat to the health of cattle have been assessed. The assessment has been performed following a methodology based on information collected by an extensive literature review and expert judgement. Details of the methodology used for this assessment are explained in a separate opinion. A global state of play on antimicrobial resistance in clinical isolates of Escherichia coli (non-VTEC), Klebsiella pneumoniae, Staphylococcus aureus, Streptococcus uberis, Streptococcus dysgalactiae, Pasteurella multocida, Mannheimia haemolytica, Histophilus somni, Mycoplasma bovis, Moraxella bovis, Fusobacterium necrophorum and Trueperella pyogenes is provided. Among those bacteria, EFSA identified E. coli and S. aureus with ≥ 66% certainty as being the most relevant antimicrobial resistant bacteria in cattle in the EU based on the available evidence. The animal health impact of these most relevant bacteria, as well as their eligibility for being listed and categorised within the animal health law framework will be assessed in separate scientific opinions. info:eu-repo/semantics/publishedVersion

Background: Necrotic laryngitis, caused by Fusobacterium necrophorum, frequently requires surgical intervention (laryngostomy) in the chronic stage. Hypothesis/Objectives: To determine survival until slaughter of cattle surgically treated for necrotic laryngitis and to identify predictors of mortality. Animals: A total of 221 cattle diagnosed with necrotic laryngitis by laryngoscopy and surgically treated Methods: Retrospective cohort study. Clinical records were matched with the national cattle identification, registration, and movement database. Information on possible predictors including clinical examination, biochemistry, and surgery was collected. A multivariable Cox proportional hazard model was used to identify predictors of mortality. Results: The overall survival rate was 65.2% and 58.6% of the animals with a completed life cycle could be slaughtered. Animals

Optimization of antimicrobial treatment is a cornerstone in the fight against antimicrobial resistance. Various national and international authorities and professional veterinary and farming associations have released generic guidelines on prudent antimicrobial use in animals. However, these generic guidelines need to be translated into a set of animal species- and disease-specific practice recommendations. This article focuses on prevention of antimicrobial resistance and its complex relationship with treatment efficacy, highlighting key situations where the current antimicrobial drug products, treatment recommendations, and practices may be insufficient to minimize antimicrobial selection. The authors address this topic using a multidisciplinary approach involving microbiology, pharmacology, clinical medicine, and animal husbandry. In the first part of the article, we define four key targets for implementing the concept of optimal antimicrobial treatment in veterinary practice: (i) reduction of overall antimicrobial consumption, (ii) improved use of diagnostic testing, (iii) prudent use of second-line, critically important antimicrobials, and (iv) optimization of dosage regimens. In the second part, we provided practice recommendations for achieving these four targets, with reference to specific conditions that account for most antimicrobial use in pigs (intestinal and respiratory disease), cattle (respiratory disease and mastitis), dogs and cats (skin, intestinal, genitourinary, and respiratory disease), and horses (upper respiratory disease, neonatal foal care, and surgical infections). Lastly, we present perspectives on the education and research needs for improving antimicrobial use in the future.

Members of the highly heterogeneous family Pasteurellaceae cause a wide variety of diseases in humans and animals. Antimicrobial agents are the most powerful tools to control such infections. However, the acquisition of resistance genes, as well as the development of resistance-mediating mutations, significantly reduces the efficacy of the antimicrobial agents. This article gives a brief description of the role of selected members of the family Pasteurellaceae in animal infections and of the most recent data on the susceptibility status of such members. Moreover, a review of the current knowledge of the genetic basis of resistance to antimicrobial agents is included, with particular reference to resistance to tetracyclines, β-lactam antibiotics, aminoglycosides/aminocyclitols, folate pathway inhibitors, macrolides, lincosamides, phenicols, and quinolones. This article focusses on the genera of veterinary importance for which sufficient data on antimicrobial susceptibility and the detection of resistance genes are currently available ( Pasteurella , Mannheimia , Actinobacillus , Haemophilus , and Histophilus ). Additionally, the role of plasmids, transposons, and integrative and conjugative elements in the spread of the resistance genes within and beyond the aforementioned genera is highlighted to provide insight into horizontal dissemination, coselection, and persistence of antimicrobial resistance genes. The article discusses the acquisition of diverse resistance genes by the selected Pasteurellaceae members from other Gram-negative or maybe even Gram-positive bacteria. Although the susceptibility status of these members still looks rather favorable, monitoring of their antimicrobial susceptibility is required for early detection of changes in the susceptibility status and the newly acquired/developed resistance mechanisms.

In a four-period, cross-over study, the fluoroquinolone antibacterial drugmarbofloxacin (MB) was administered to calves, alone and in combination withthe nonsteroidal anti-inflammatory drug tolfenamic acid (TA). Both drugs wereadministered intramuscularly (IM) at doses of 2 mg⁄ kg. A tissue cage model ofinflammation, based on the actions of the mild irritant carrageenan, was usedto evaluate the pharmacokinetics (PK) of MB and MB in combination with TA.MB mean values of area under concentration–time curve (AUC) were15.1 lgÆh⁄ mL for serum, 12.1 lgÆh⁄ mL for inflamed tissue cage fluid (exudate)and 9.6 lgÆh⁄ mL for noninflamed tissue cage fluid (transudate). Values of Cmaxwere 1.84, 0.35 and 0.31 lg ⁄ mL, respectively, for serum, exudate andtransudate. Mean residence time (MRT) of 23.6 h (exudate) and 22.6 h(transudate) also differed significantly from serum MRT (8.6 h). Co-administrationof TA did not affect the PK profile of MB. The pharmacodynamics of MBwas investigated using a bovine strain of Mannheimia haemolytica. Time–killcurves were established ex vivo on serum, exudate and transudate samples.Modelling the ex vivo serum time–kill data to the sigmoid Emax equationprovided AUC24 h ⁄ MIC values required for bacteriostatic (18.3 h) and bactericidalactions (92 h) of MB and for virtual eradication of the organism was139 h. Corresponding values for MB + TA were 20.1, 69 and 106 h. Thesedata were used to predict once daily dosage schedules for a bactericidal action,assuming a MIC90 value of 0.24 lg ⁄ mL, a dose of 2.6 mg⁄ kg for MB and2.19 mg⁄ kg for MB + TA were determined, which are similar to the currentlyrecommended dose of 2.0 mg⁄ kg.

In a four-period, cross-over study, the fluoroquinolone antibacterial drug marbofloxacin (MB) was administered to calves, alone and in combination with the nonsteroidal anti-inflammatory drug tolfenamic acid (TA). Both drugs were administered intramuscularly (IM) at doses of 2 mg/kg. A tissue cage model of inflammation, based on the actions of the mild irritant carrageenan, was used to evaluate the pharmacokinetics (PK) of MB and MB in combination with TA. MB mean values of area under concentration-time curve (AUC) were 15.1 μg·h/mL for serum, 12.1 μg·h/mL for inflamed tissue cage fluid (exudate) and 9.6 μg·h/mL for noninflamed tissue cage fluid (transudate). Values of C(max) were 1.84, 0.35 and 0.31 μg/mL, respectively, for serum, exudate and transudate. Mean residence time (MRT) of 23.6 h (exudate) and 22.6 h (transudate) also differed significantly from serum MRT (8.6 h). Co-administration of TA did not affect the PK profile of MB. The pharmacodynamics of MB was investigated using a bovine strain of Mannheimia haemolytica. Time-kill curves were established ex vivo on serum, exudate and transudate samples. Modelling the ex vivo serum time-kill data to the sigmoid E(max) equation provided AUC(24 h) /MIC values required for bacteriostatic (18.3 h) and bactericidal actions (92 h) of MB and for virtual eradication of the organism was 139 h. Corresponding values for MB + TA were 20.1, 69 and 106 h. These data were used to predict once daily dosage schedules for a bactericidal action, assuming a MIC(90) value of 0.24 μg/mL, a dose of 2.6 mg/kg for MB and 2.19 mg/kg for MB + TA were determined, which are similar to the currently recommended dose of 2.0 mg/kg., Facultad de Ciencias Veterinarias

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.