Background: Sepsis is a life-threatening disease for which critically important antimicrobials (CIA) frequently are used. Diagnostic and therapeutic guidelines for sepsis and critically ill calves are largely lacking. Objectives: Identify factors associated with mortality in critically ill calves and describe bacteria obtained from blood cultures of critically ill calves with sepsis and their antimicrobial resistance. Animals: Two-hundred thirty critically ill calves, mainly Belgian Blue beef cattle. Methods: Retrospective cohort study. Logistic regression, survival analysis, and decision tree analysis were used to determine factors associated with mortality. Results: Of the critically ill calves, 34.3% had sepsis and 61.3% died. The final survival model indicated that calves with sepsis (hazard risk [HR]: 1.6; 95% confidence interval [CI]: 1.0-2.5; P = .05), abnormal behavior (HR: 2.3; 95% CI: 1.3-4.0; P = .005), and hypothermia (HR: 0.82; 95% CI: 0.72-0.95; P = .01) had a significantly higher mortality risk. In a second survival model, hypothermia (HR: 0.87; 95% CI: 0.78-0.96; P = .004) and hypoglycemia (HR: 2.2; 95% CI: 1.5-3.3; P < .001) were risk factors for mortality. Decision tree analysis emphasized the importance of behavior, hypochloremia, hypoglycemia, hyperkalemia, and lung ultrasonography for mortality risk. Escherichia coli (30.6%) was most frequently isolated from blood cultures, of which 90.9% were multidrug resistant. Inappropriate use of antimicrobials was frequent for penicillin, amoxicillin, and sulfamethoxazole/trimethoprim, but less for CIA. Conclusions and Clinical Importance: Many critically ill calves have sepsis, which increases mortality risk. Bacteria involved are often resistant to first-intention antimicrobials but less resistant to CIA. The other identified risk factors for mortality can support therapeutic decision-making.

The primary objective of this study was to determine associations between ultrasound-based classification systems (using maximum consolidations depth, number of quadrants with consolidation, and consolidation location), clinical indicators, and performance outcomes (ultrasonographic cure, ADG, and cold carcass weight [CCW]) in veal calves following oral metaphylaxis. A retrospective cohort study was conducted on 1,090 white veal calves originating from 3 Belgian veal herds. Clinical scoring and quick thoracic ultrasound (qTUS) follow-up were done by 4 experienced operators at arrival (wk 0), at the start of the first metaphylactic treatment with doxycycline (treatment initiation, wk 1), at the end of this metaphylactic treatment (short-term evaluation, wk 3) and on a long-term evaluation point (wk 10-12). Cure was defined as complete reaeration of previously consolidated lung tissue. Pathogens were identified using culture and nanopore sequencing. One week after arrival, healthy lungs (no consolidation), mild pneumonia (consolidation <1 cm), moderate pneumonia (consolidation ≥1 but <3 cm), and severe pneumonia (consolidation ≥3 cm) were identified in 46.9%, 12.4%, 21.4%, and 19.4% of calves, respectively. Short-term cure was 59.3% for calves with mild pneumonia, 50.2% for calves with moderate pneumonia, and 32.7% for calves with severe pneumonia, resulting in a total short-term cure of 45.9%. Coronavirus, respiratory syncytial virus, influenza D virus, and Mycoplasmopsis bovis were circulating during treatment. At the long-term evaluation point (wk 10-12), final cure was 59.3%, 55.8%, and 40.3% for calves with mild, moderate, and severe pneumonia at treatment initiation, respectively. Multivariable regression models indicated that different interactions between qTUS categories and number of affected quadrants were associated with short- and long-term odds of cure. Generated models resulted in 3 classification methods, either based on maximum consolidation depth, number of affected quadrants, or an integrated system of both. Calves with clinical pneumonia (Wisconsin score ≥5 and lung consolidation ≥1 cm) had decreased short-term odds to be cured after metaphylaxis compared with calves with subclinical pneumonia (Wisconsin score <5 and lung consolidation ≥1 cm; odds ratio = 0.43; 95% CI: 0.27-0.67). For calves with severe pneumonia in wk 10-12, when compared with calves in a lower qTUS category, ADG and CCW were reduced by 104 g/d (SD = 13; 95% CI: 78-130) and 7.1 kg (SD = 1.9; 95% CI: 3.4-10.9), respectively. Categorization based on maximum consolidation depth, the number of affected quadrants, or an integrated system of both has the potential to be included in an ultrasound scoring system. However, based on the practicality for recording, reporting, and follow-up, the authors recommend categorizing calves into mild, moderate, and severe pneumonia based on maximum consolidation depth measurement, referred to as qTUS score, as a practical classification system for ultrasonographic lung assessment in calves.

Background: Sepsis is a main contributor to calf mortality, but diagnosis is difficult. Objectives: Develop and validate a predictive model for bacteremia in critically ill calves (CIC). Animals: A total of 334 CIC, sampled for blood culture. Methods: Cross-sectional study. Multivariable logistic regression and classification tree analysis on clinical, ultrasonographic, and laboratory variables were performed on a dataset including all animals. Model validation was done on 30% of the dataset. Similar statistics (except validation) were performed on a subset of the database (n = 143), in which presumed contaminants were excluded. Results: The best performing model to predict bacteremia, taking all detected bacteria into account, included tachypnea, tachycardia, acidemia, hypoglycemia, venous hypoxemia, and hypoproteinemia. Sensitivity and specificity of this model were 70.6% and 98.0%, respectively, but decreased to 61.5% and 91.7% during model validation. The best-performing model, excluding presumed contaminants, included abnormal temperature, heart rate, absence of enteritis, hypocalcemia, and hyperlactatemia as risk factors for bacteremia. Sensitivity and specificity of this model were 71.4% and 93.9%, respectively. Both classification trees performed less well in comparison to logistic regression. The classification tree excluding presumed contaminants, featured hypoglycemia, absence of diarrhea, and hyperlactatemia as risk factors for bacteremia. Sensitivity and specificity were 39.4% and 92.7%, respectively. Conclusions and Clinical Importance: Hypoglycemia, hyperlactatemia, and hypoproteinemia seem relevant in assessing bacteremia in CIC. The performance of these models based on basic clinical and blood variables remains insufficient to predict bacteremia.

Background: Sepsis is a life-threatening condition for which critically important antimicrobials are often indicated. The value of blood culture for sepsis is indisputable, but appropriate guidelines on sampling and interpretation are currently lacking in cattle. Objective: Compare the diagnostic accuracy of 2 blood culture media (pediatric plus [PP] and plus aerobic [PA]) and hypoglycemia for bacteremia detection. Estimate the contamination risk of blood cultures in critically ill calves. Animals: One hundred twenty-six critically ill calves, 0 to 114 days. Methods: Retrospective cross-sectional study in which the performance of PP, PA and hypoglycemia to diagnose sepsis was assessed using a Bayesian latent class model. A Cox proportional hazards model was used to compare time to positivity (TTP). Potential contamination was descriptively analyzed. Isolates were considered relevant when they were; member of the Enterobacterales, isolated from both blood cultures vials, or well-known, significant bovine pathogens. Results: The sensitivities for PP, PA, and hypoglycemia were higher when excluding assumed contaminants; 68.7% (95% credibility interval = 30.5%-93.7%), 87.5% (47.0%-99.5%), and 61.3% (49.7%-72.4%), respectively. Specificity was estimated at 95.1% (82.2%-99.7%), 94.2% (80.7%-99.7%), and 72.4% (64.6%-79.6%), respectively. Out of 121 interpretable samples, 14.9% grew a presumed contaminant in PA, PP, or both. There was no significant difference in the TTP between PA and PP. Conclusions and Clinical Importance: PA and PP appear to outperform hypoglycemia as diagnostic tests for sepsis. PA seems most sensitive, but a larger sample size is required to verify this. Accuracy increased greatly after excluding assumed contaminants. The type of culture did not influence TTP or the contamination rate.

Sepsis is a frequent life-threatening condition in young calves, requiring rapid broad spectrum and bactericidal therapy to maximize survival chances. Few studies have identified and characterized bacteria involved in sepsis in calves. This report demonstrates the involvement of a multidrug resistant Raoultella ornithinolytica, an emerging pathogen in human medicine, in a calf with suspected sepsis. R. ornithinolytica was identified by MALDI-TOF MS from blood cultures of a critically ill calf. Susceptibility testing showed phenotypic resistance against ampicillin, gentamicin, potentiated sulphonamides, streptomycin, tetracyclines and intermediate susceptibility for enrofloxacin. Whole genome sequencing confirmed identification as R. ornithinolytica and the multidrug resistant character of the isolate. Antimicrobial resistance genes acting against aminoglycosides, beta-lactam antibiotics, fosfomycin, quinolones, sulphonamides, trimethoprim and tetracyclines were found. The calf recovered after empirical parenteral therapy with enrofloxacin and sodium penicillin for seven days. Ancillary therapy consisted of fluid therapy, ketoprofen and doxapram hydrochloride. To the authors' knowledge, this is the first report characterizing a multidrug resistant R. ornithinolytica isolate from blood culture in cattle. It is currently unknown whether animals and farms may act as reservoirs for multidrug resistant R. ornithinolytica strains.

Background: The care of sick neonatal foals is labor-intensive and costly. Prediction of risk of death upon admission is often difficult but might support decision-making. Objectives: To determine diseases and risk factors associated with death in neonatal hospitalized foals. Animals: Two hundred twenty-two hospitalized foals, ≤7 days old. Methods: Retrospective cohort study. Clinical and laboratory variables were evaluated for their association with death by means of Cox survival analysis and by classification and regression tree (CART) analysis. Results: Most prevalent diseases were sepsis (43.9%), enteritis (14.0%), and omphalitis (9.0%). Case fatality rate was 33.3%. Neonatal sepsis significantly increased the risk of death (hazard ratio [HR] = 1.9; 95% confidence interval [CI] = 1.2-3.0; P = .009). Multivariable Cox regression in foals ≤7 days old revealed comatose mental state (HR = 2.9; 95% CI = 1.1-8.1; P = .04), L-lactatemia (≥373.8 mg/L [4.2 mmol/L]; HR = 4.4; 95% CI = 1.7-11.7; P = .003) and increased serum amyloid A (SAA; ≥2054 μg/mL; HR = 3.9; 95% CI = 1.2-12.7; P = .02) as risk factors for death, with a sensitivity and specificity of 7.5% and 95.7%, respectively. The CART analysis highlighted L-lactatemia, comatose mental state, and hypercapnia as risk factors for death, with a sensitivity of 38.1% and specificity of 86.1% after validation. Conclusions and Clinical Importance: In this study sample, sepsis was associated with the highest risk of death. Identified risk factors such as SAA, L-lactate, and comatose mental state might guide veterinarians and owners in better decision-making for economic or welfare reasons. Frequently measured laboratory variables, such as blood glucose concentration and Immunoglobulin G, were not sensitive and specific enough to provide reliable decision support for survival estimation.