Comparing Healthcare Needs in Extremely Low Birth Weight Infants With NEC and Spontaneous Intestinal Perforation.

BACKGROUND: Necrotizing enterocolitis (NEC) and spontaneous intestinal perforation (SIP) affect 6-8% of extremely low birth weight (ELBW) infants. SIP has lower mortality than NEC, but with similar short-term morbidity in length of stay, growth failure, and supplemental oxygen requirements. Comparative long-term neurodevelopmental outcomes have not been clarified. METHODS: Data were prospectively collected from 59 North American neonatal units, regarding ELBW infants (401-1000 g or 22-27 weeks gestational age) born between 2011 and 2018 and evaluated again at 16-26 months corrected age. Outcomes were collected from infants with laparotomy-confirmed NEC, laparotomy-confirmed SIP, and those without NEC or SIP. The primary outcome was severe neurodevelopmental disability. Secondary outcomes were weight <10th percentile, medical readmission, post-discharge surgery and medical support at home. Adjusted risk ratios (ARR) were calculated. RESULTS: Of 13,673 ELBW infants, 6391 (47%) were followed including 93 of 232 (40%) with NEC and 100 of 235 (42%) with SIP. There were no statistically significant differences in adjusted risk of any outcomes when directly comparing NEC to SIP (ARR 2.35; 95% CI 0.89, 6.26). However, infants with NEC had greater risk of severe neurodevelopmental disability (ARR 1.43; 1.09-1.86), rehospitalization (ARR 1.46; 1.17-1.82), and post-discharge surgery (ARR 1.82; 1.48-2.23) compared to infants without NEC or SIP. Infants with SIP only had greater risk of post-discharge surgery (ARR 1.64; 1.34-2.00) compared to infants without NEC or SIP. CONCLUSIONS: ELBW infants with NEC had significantly increased risk of severe neurodevelopmental disability and post-discharge healthcare needs, consistent with prior literature. We now know infants with SIP also have increased healthcare needs. LEVELS OF EVIDENCE: Level II.

Impacts of preweaning colostrum feeding practices and health measures on dairy cow production, while accounting for genetic potential.

Calf management and health are essential for setting up the foundation of a productive cow. The objectives of this study were to estimate the impact of preweaning practices on milk production parameters while accounting for an animal's genetic potential in New Brunswick, Canada. A retrospective cohort study was performed on 220 heifer calves from eight herds born in 2014-2015. Preweaning practices and health data were recorded by producers and reviewed by the herd veterinarian for each calf. The herd veterinarian also visited the farms to collect serum samples from calves and frozen colostrum samples. The production outcomes assessed were milk, protein and fat yields, standardized to 305 d for the first lactation (L1) and a combined group of lactations two and three (L2 + 3). The genomic potential was determined as genomic parent averages (GPA) for the associated production parameters. Analysis was performed with multivariable linear (L1) and linear mixed (L2 + 3) regression models. In L1, for every 1.0 kg increase in weaning weight, milk, protein, and fat yield increased by 25.5, 0.82, and 1.01 kg, respectively (P < 0.006). Colostrum feeding time (CFT) positively impacted L1 milk and protein production, with feeding between 1-2 h of life producing the greatest estimates of 626 kg of milk and 18.2 kg of protein yield (P < 0.007), compared to earlier or later CFT. Fat yield production was decreased by 80.5 kg (P < 0.006) in L1 when evaluating animals that developed a preweaning disease and were not treated with antibiotics compared to healthy untreated animals. Impacts on L2 + 3 were similar across all production outcomes, with a positive interaction effect of CFT and weaning weight. Compared to CFT < 1 h, the later CFT groups of 1-2 h and > 2 h produced greater yield outcomes of 68.2 to 72.6 kg for milk (P < 0.006), 2.06 to 2.15 kg for protein (P < 0.005), and 1.8 to 1.9 kg for fat (P < 0.045) for every 1 kg increase of weaning weight, respectively. The fit of all models was significantly improved with the inclusion of GPA. These results indicate that colostrum management and preweaning health measures impacted production parameters as adults. The inclusion of GPA significantly improved the accuracy of the models, indicating that this can be an important parameter to include in future studies.

The impact of calf management and health events have been predominately investigated during the preweaning period. However, calfhood events could also impact the animal's health and productivity as an adult. Results from this study indicate that colostrum feeding time and weaning weight were associated with production outcomes (milk, protein, and fat yields) across the first three lactations, and disease and antibiotic treatment can be detrimental to fat yield in the first lactation. By including genetic potential in the assessment of preweaning colostrum practices and health measures on production outcomes, we can more precisely identify areas to optimize calf management.

Predictors of Mortality in Very Low Birth Weight Neonates With Congenital Diaphragmatic Hernia.

BACKGROUND: Limited data exists regarding the mortality of very low birth weight (VLBW) neonates with congenital diaphragmatic hernia (CDH). This study aims to quantify and determine predictors of mortality in VLBW neonates with CDH. METHODS: This analysis of 829 U.S. NICUs included VLBW [birth weight ≤1500g] neonates, born 2011-2021 with and without CDH. The primary outcome was in-hospital mortality. A generalized estimating equation regression model determined the adjusted risk ratio (ARR) of mortality. RESULTS: Of 426,140 VLBW neonates, 535 had CDH. In neonates with CDH, 48.4% had an additional congenital anomaly vs 5.5% without. In-hospital mortality for neonates with CDH was 70.4% vs 12.6% without. Of those with CDH, 73.3% died by day of life 3. Of VLBW neonates with CDH, 38% were repaired. A subgroup analysis was performed on 60% of VLBW neonates who underwent delivery room intubation or mechanical ventilation, as an indicator of active treatment. Mortality in this group was 62.7% for neonates with CDH vs 16.4% without. Higher Apgars at 1 min and repair of CDH were associated with lower mortality (ARR 0.91; 95%CI 0.87,0.96 and ARR 0.28; 0.21,0.39). The presence of additional congenital anomalies was associated with higher mortality (ARR 1.14; 1.01,1.30). CONCLUSION: These benchmark data reveal that VLBW neonates with CDH have an extremely high mortality. Almost half of the cohort have an additional congenital anomaly which significantly increases the risk of death. This study may be utilized by providers and families to better understand the guarded prognosis of VLBW neonates with CDH. TYPE OF STUDY: Level II. LEVEL OF EVIDENCE: Level II.

Factors associated with D-lactic acidosis in pediatric intestinal failure: A case-control study.

BACKGROUND: D-lactic acidosis (DLA) is a serious complication of short bowel syndrome (SBS) in children with intestinal failure (IF). Malabsorbed carbohydrates are metabolized by bacteria in the intestine to D-lactate which can lead to metabolic acidosis and neurologic symptoms. METHODS: A retrospective chart review was performed in children ≤18 years old with SBS who had one of the following criteria: unexplained metabolic acidosis, neurologic signs or symptoms, history of antibiotic therapy for small bowel bacterial overgrowth, or high clinical suspicion of DLA. Cases had serum D-lactate concentration >0.25 mmol/L; controls with concentrations ≤0.25 mmol/L. RESULTS: Of forty-six children, median age was 3.16 (interquartile range (IQR): 1.98, 5.82) years, and median residual bowel length was 40 (IQR: 25, 59) cm. There were 23 cases and 23 controls. Univariate analysis showed that cases had significantly lower median bicarbonate (19 vs. 24 mEq/L, p = 0.001), higher anion gap (17 vs. 14 mEq/L, p < 0.001) and were less likely to be receiving parenteral nutrition, compared with children without DLA. Multivariable analysis identified midgut volvulus, history of intestinal lengthening procedure, and anion gap as significant independent risk factors. Midgut volvulus was the strongest independent factor associated with DLA (adjusted odds ratio = 17.1, 95% CI: 2.21, 133, p = 0.007). CONCLUSION: DLA is an important complication of pediatric IF due to SBS. Patients with IF, particularly those with history of midgut volvulus, having undergone intestinal lengthening, or with anion gap acidosis, should be closely monitored for DLA.

Association between neurodevelopmental outcomes and concomitant presence of NEC and IVH in extremely low birth weight infants.

OBJECTIVE: To quantify the association between necrotizing enterocolitis (NEC) and neurodevelopmental disability (NDI) in extremely low birth weight (ELBW) infants with intraventricular hemorrhage (IVH). STUDY DESIGN: ELBW survivors born 2011-2017 and evaluated at 16-26 months corrected age in the Vermont Oxford Network (VON) ELBW Follow-Up Project were included. Logistic regression determined the adjusted relative risk (aRR) of severe NDI in medical or surgical NEC compared to no NEC, stratified by severity of IVH. RESULTS: Follow-up evaluation occurred in 5870 ELBW survivors. Compared to no NEC, medical NEC had no impact on NDI, regardless of IVH status. Surgical NEC increased risk of NDI in patients with no IVH (aRR 1.69; 95% CI 1.36-2.09), mild IVH (aRR 1.36;0.97-1.92), and severe IVH (aRR 1.35;1.13-1.60). CONCLUSIONS: ELBW infants with surgical NEC carry increased risk of neurodevelopmental disability within each IVH severity stratum. These data describe the additive insult of surgical NEC and IVH on neurodevelopment, informing prognostic discussions and highlighting the need for preventative interventions.

Factors Associated With Chronic Intestinal Inflammation Resembling Inflammatory Bowel Disease in Pediatric Intestinal Failure: A Matched Case-Control Study.

BACKGROUND AND AIMS: There is a subset of intestinal failure patients with associated chronic intestinal inflammation resembling inflammatory bowel disease. This study aimed to evaluate factors associated with chronic intestinal inflammation in pediatric intestinal failure. METHODS: This was a single-center retrospective case-control study of children <18 years old with intestinal failure. Cases were defined by abnormal amounts of chronic intestinal inflammation on biopsies. Children with diversion colitis, eosinophilic colitis, or isolated anastomotic ulceration were excluded. Cases were matched 1:2 to intestinal failure controls based on sex, etiology of intestinal failure, and duration of intestinal failure. Multivariable conditional logistic regression was used to compare clinical factors between cases and controls, accounting for clustering within matched sets. A subgroup analysis was performed assessing factors associated with escalation of anti-inflammatory therapy. RESULTS: Thirty cases were identified and matched to 60 controls. On univariate analysis, longer parenteral nutrition (PN) duration (1677 vs 834 days, P = 0.03), current PN use (33.3% vs 20.0%, P = 0.037), and culture-proven bacterial overgrowth (53.3% vs 31.7%, P = 0.05) were associated with chronic intestinal inflammation. On multivariable analysis, no variable reached statistical significance. On subgroup analysis, duration of intestinal failure, location of inflammation, and worst degree of inflammation on histology were associated with escalation of therapy. CONCLUSIONS: PN dependence and intestinal dysbiosis are associated with chronic intestinal inflammation in children with intestinal failure. Severity of inflammation is associated with escalation of therapy. Further analysis is needed to assess these associations and the efficacy of treatments in this population.

Impact of concomitant necrotizing enterocolitis on mortality in very low birth weight infants with intraventricular hemorrhage.

OBJECTIVE: To evaluate the impact of necrotizing enterocolitis (NEC) on mortality in very low birth weight (VLBW) infants with intraventricular hemorrhage (IVH). STUDY DESIGN: Data were collected on VLBW infants born 2014-2018 at Vermont Oxford Network (VON) centers. NEC and IVH were categorized by severity. Adjusted risk ratios (ARR) for in-hospital mortality were calculated. RESULTS: This study included 187 187 VLBW infants. Both medical and surgical NEC increased mortality risk compared to those without NEC. Stratification by IVH severity modified this effect (no IVH: ARR 3.04 (95%CI 2.74-3.38) for medical NEC and 4.17 (3.84-4.52) for surgical NEC; mild IVH: ARR 2.14 (1.88-2.44) for medical NEC and 2.49 (2.24-2.78) for surgical NEC; severe IVH: ARR 1.14 (1.03-1.26) for medical NEC and 1.10 (1.02-1.18) for surgical NEC). CONCLUSION: The relative impact of NEC on mortality decreased as IVH severity increased. Given the frequent coexistence of NEC and IVH, these data inform multidisciplinary management of these complex patients.

High Rate of Venous Thromboembolism in Severe Pediatric Intestinal Failure.

OBJECTIVE: To quantify the rate of venous thromboembolism (VTE) in patients with pediatric intestinal failure and identify associated risk factors. STUDY DESIGN: We performed a retrospective cohort study in pediatric patients (<21 years old) with severe pediatric intestinal failure (≥90 consecutive days of parenteral nutrition) secondary to short bowel syndrome who were treated from 2014 to 2021 at an interdisciplinary intestinal rehabilitation program. The primary outcome was the incidence of VTE. Multivariable regression was performed to identify independent clinical predictors of VTE. RESULTS: A total of 263 patients (59.7% male) met the criteria for inclusion. The cumulative incidence of VTE was 28.1%, with a rate of 0.32 VTEs per 1000 catheter-days. On univariate analysis, the number of catheter days, number of catheters, and history of central line-associated blood stream infection were associated with VTE. On multivariable logistic regression, a higher number of catheters was an independent risk factor for VTE (aOR, 1.17; 95% CI, 1.06-1.29). Additionally, earlier gestational age was a risk factor for VTE such that every week decrease in gestational age conferred a 9% increased risk of VTE (aOR, 1.09; 95% CI, 1.02-1.16). CONCLUSIONS: In this retrospective study, 28.1% of patients with severe pediatric intestinal failure developed VTE; the number of catheters and early gestational age were noted to be independent risk factors for VTE. This high incidence of VTE highlights the need to investigate VTE in pediatric intestinal failure prospectively, including the potential benefit of prophylactic anticoagulation.

Autoimmune Thyroiditis and Risk of Malignancy in Children with Thyroid Nodules.

Background: It is uncertain whether the presence of autoimmune thyroiditis (AIT) increases the risk of thyroid cancer in children with thyroid nodules. This study evaluated the association between AIT and thyroid cancer in pediatric patients with thyroid nodules. Methods: A cross-sectional study was performed of pediatric patients (<19 years old) with a thyroid nodule (≥1 cm) who underwent fine-needle aspiration in an academic pediatric thyroid center. AIT was defined by the presence of thyroid autoantibodies or diffusely heterogeneous sonographic echotexture. The primary outcome was diagnosis of thyroid cancer. The association of AIT with thyroid cancer was evaluated with univariable and multivariable logistic regression. Associations of AIT with subject and nodule characteristics were also assessed. Results: Four hundred fifty-eight thyroid nodules in 385 patients (81% female) were evaluated at a median age of 15.5 years (interquartile range 13.5-17.0). Thyroid cancer was present in 108 nodules (24%). AIT was present in 95 subjects (25%) and was independently associated with an increased risk of thyroid cancer (multivariable odds ratio [OR] 2.19, 95% confidence interval [CI] 1.32-3.62). Thyroid cancer was also independently associated with younger age, nodule size, and solitary nodules, but was not associated with serum thyrotropin concentration. AIT was not associated with the likelihood of subjects undergoing thyroid surgery (p = 0.17). AIT was less commonly associated with follicular thyroid carcinoma than with papillary thyroid carcinoma (OR 0.22, CI 0.05-1.06). Among papillary thyroid carcinomas, AIT was strongly associated with the diffuse sclerosing variant (OR 4.74, CI 1.33-16.9). AIT was not associated with the extent of local, regional, or distant disease at thyroid cancer diagnosis. Conclusions: AIT is independently associated with an increased risk of thyroid cancer in children with thyroid nodules. These findings suggest that the evaluation of thyroid autoantibodies and thyroid echotexture may inform thyroid cancer risk assessment and surgical decision-making in children with thyroid nodules.

Antibiotic Therapy for Culture-Proven Bacterial Overgrowth in Children With Intestinal Failure Results in Improved Symptoms and Growth.

OBJECTIVES: To evaluate symptoms, enteral tolerance, growth, and antibiotic regimens in pediatric intestinal failure (IF) patients after treated with antibiotic therapy for small bowel bacterial overgrowth (SBBO). METHODS: Single-center retrospective review of children 0-18 years with IF with endoscopic cultures demonstrating >10 5 CFU/mL from 2010 to 2017. Symptoms, enteral tolerance, growth, and antibiotic regimens were evaluated at the time of endoscopy and 6 months later. RESULTS: Of 505 patients followed in our intestinal rehabilitation program, 104 underwent upper gastrointestinal endoscopy and 78 had positive duodenal cultures. Clinical data pre- and post-endoscopy were available for 56 patients. Compared to baseline, in the 6 months following targeted antibiotic treatment, children showed significant improvement in emesis or feeding intolerance (58.9% vs 23.2%, P < 0.001), abdominal pain (16.1% vs 7.1%, P = 0.02), high stool output (42.9% vs 19.6%, P = 0.002), and gross GI bleeding (19.6% vs 3.6%, P = 0.003). Mean BMI-for-age z scores increased significantly (-0.03 ± 0.94 vs 0.27 ± 0.82, P = 0.03); however, height-for-age z scores, weight-for-age z scores, and percent of calories from enteral intake were not significantly different after therapy. Antibiotic regimens remained highly variable. CONCLUSIONS: Children with IF and culture-positive SBBO showed significant improvement in symptoms and BMI-for-age z scores after duodenal culture with subsequent targeted antibiotic therapy. Longer follow-up may be needed to detect improvements in linear growth and percent of calories from enteral feeds. Antibiotic regimens remain highly variable. Long-term consequences of chronic antimicrobial therapy, including antimicrobial resistance, remain unknown. Prospective studies focused on standardizing duodenal sampling technique, correlating culture and pathology data, and evaluating antibiotic resistance patterns are needed.

Puberty and growth in patients with pediatric intestinal failure.

BACKGROUND: Pediatric intestinal failure (PIF) affects nutrition, metabolism, and endocrine development, but its downstream impact on puberty is unknown. METHODS: A retrospective review was performed of patients age >8 years with PIF managed at an intestinal rehabilitation program. Outcomes of interest were peak height velocity (PHV), age at PHV, and age at pubertal onset (Tanner stage 2). Outcomes were stratified by sex and compared to established norms. RESULTS: Of 110 patients with PIF, 54.5% were male. Compared to the CDC 50th percentile, PHV in PIF patients was similar for females (8.09±2.36 vs. 7.37 cm/yr;p = 0.23) but significantly higher for males (9.27±2.56 vs. 7.91 cm/yr;p = 0.038). Age at PHV in PIF patients was significantly younger for both males (12.31±2.14 vs. 13.38 years;p = 0.049) and females (10.70±1.06 vs. 11.71 years;p = 0.001). PIF patients reached pubertal onset earlier than published norms; this was significant for males (12.41±1.80 vs. 13.44 years;p = 0.014), but not for females (10.45±1.81 vs. -11.15 years;p = 0.13). The mean height-for-age Z-score was -1.2, with 20% of patients having a Z-score less than -2. CONCLUSIONS: Pubertal onset and growth are neither delayed nor diminished in patients with PIF. The high incidence of short stature, however, highlights the importance of optimizing prepubertal linear growth to attain full height potential. TYPE OF STUDY: Prognosis study (Retrospective cohort study).

Morbidity associated with laparotomy-confirmed spontaneous intestinal perforation: A prospective multicenter analysis.

BACKGROUND: Differences in morbidities between spontaneous intestinal perforation (SIP) and necrotizing enterocolitis (NEC) are unknown. METHODS: Prospectively collected multicenter data regarding very low birth weight (VLBW) infants 2015-2019 were analyzed. Diagnosis of SIP or NEC was laparotomy-confirmed in all patients. Multivariable regression modeling was used to assess adjusted length of stay (LOS; primary outcome) and adjusted risk ratios (ARR) for weight <10th percentile at discharge, and supplemental oxygen requirement at discharge. RESULTS: Of 201,300 VLBW infants at 790 hospitals, 1523 had SIP and 2601 had NEC. Adjusted LOS was similar for SIP and NEC (92 vs 88 days, p = 0.08561), but significantly higher than seen without SIP or NEC (68 days, p<0.0001). The risk of growth morbidity at discharge was similar between SIP and NEC (74.2% vs 75.3%; ARR:1.00;0.94,1.06), but higher than infants without SIP or NEC (47.7%; ARR:0.50;0.47,0.53). Infants with NEC were less likely to require supplemental oxygen at discharge than infants with SIP (24.4% vs 34.9%; ARR:0.80; 0.71,0.89). CONCLUSIONS: Although mortality is known to be lower in VLBW infants with SIP than NEC, this study highlights the similarly high morbidity experienced by both groups of infants. These benchmark data can help align counseling of families with expected outcomes. LEVEL OF EVIDENCE: Level II. TYPE OF STUDY: Prognosis study (Cohort Study).

Current outcomes of infants with esophageal atresia and tracheoesophageal fistula: A multicenter analysis.

OBJECTIVE: This study aims to quantify mortality rates and hospital lengths of stay (LOS) in neonates with esophageal atresia and tracheoesophageal fistula (EA/TEF), and to characterize the effects of birth weight (BW) and associated congenital anomalies upon these. METHODS: Data regarding patients with EA/TEF were prospectively collected (2013-2019) at 298 North American centers. The primary outcome was mortality and secondary outcome was LOS.  Risk factors affecting mortality and LOS were assessed. RESULTS: EA/TEF was diagnosed in 3290 infants with a median BW of 2476 g (IQR 1897,2970). In-hospital mortality was 12.7%. Mortality was inversely correlated with BW. After adjustment, the risk of mortality decreased by approximately 11% with every 100 g increase in BW. A significant congenital anomaly other than EA/TEF was diagnosed in 37.9% of patients. Risk of mortality increased in patients with associated congenital anomalies, most notably in those with a severe cardiac anomaly. Lower BW was associated with an increased mean LOS among survivors. Similar to mortality risk, additional anomalies were associated with prolonged LOS. CONCLUSIONS: This study demonstrates an in-hospital mortality of over 10%. Both increased mortality and prolonged LOS are highly associated with lower birth weight and the presence of concomitant congenital anomalies.

Long-term assessment of bilirubin and transaminase trends in pediatric intestinal failure patients during the era of hepatoprotective parenteral nutrition.

PURPOSE: This study aimed to characterize the relationship between hepatoprotective parenteral nutrition (PN) dependence and long-term serum liver tests in children with intestinal failure (IF). METHODS: A retrospective review was performed of children with severe IF (> 90 consecutive days of PN) who were followed from 2012 to 2019 at a multidisciplinary intestinal rehabilitation program. Patients were stratified into three groups based on level of PN dependence at most recent follow up: EN (achieved enteral autonomy), mixed (parenteral and enteral nutrition), and PN (> 75% of caloric intake from PN). PN at any point for this cohort was hepatoprotective, defined as soy-based lipids < 1.5 g/kg/day, combination (soy, medium chain fatty acid, olive and fish oil) lipid emulsion, or fish oil-based lipid emulsion. Kaplan-Meier analysis and a generalized estimating equation (GEE) model were utilized to estimate time to normalization and trends, respectively, of two serum markers of liver health: direct bilirubin (DB) and alanine aminotransferase (ALT). RESULTS: The study included 123 patients (67 EN, 32 mixed, 24 PN). Median follow up time was 4 years. Based on the Kaplan Meier curve, 100% of EN and mixed group patients achieved normal DB levels by 3 years, while 32% of the PN group had elevated DB levels (Fig. 1). At 5 years, 16% of EN patients had elevated ALT levels compared to 73% of PN patients (p < 0.001, Fig. 2). The PN group's ALT levels were 1.76-fold above normal at 3 years (95%CI 1.48-2.03) and 1.65-fold above normal at 5 years (95%CI 1.33-1.97, Fig. 3). CONCLUSIONS: While serum bilirubin levels tend to normalize, long-term PN dependence in the era of hepatoprotective PN is associated with a persistent transaminase elevation in an overwhelming majority of patients. These data support continued vigilant monitoring of liver health in children with intestinal failure. LEVEL OF EVIDENCE: III.

Gap between producers and veterinarians regarding biosecurity on Quebec dairy farms.

As part of the ProAction on-farm program to implement national biosecurity requirements on dairy farms, Canadian veterinarians are called upon to complete biosecurity risk assessments. The objective of the present study was consequently to understand veterinarians' perceptions of biosecurity, and to compare perceptions among producer-veterinarian pairs. Questionnaires were administered to 106 producers from Quebec and their veterinarians (n = 82), and the answers of the producer-veterinarian pairs were compared. While most veterinarians reported it was easy to discuss biosecurity with their clients, most veterinarians and producers did not report discussing biosecurity. Moreover, when producers or veterinarians reported discussing biosecurity topics, there was no agreement amongst pairs. Veterinarians also misjudged how their clients perceived the importance and usefulness of biosecurity. Finally, veterinarians reported they had the knowledge and opportunity to assess and discuss biosecurity on dairy farms but lacked skills for evaluating farms and communicating their knowledge.

Différences entre les producteurs et les vétérinaires en matière de biosécurité dans les fermes laitières du Québec. Dans le cadre du programme à la ferme ProAction visant à mettre en oeuvre les exigences nationales de biosécurité dans les fermes laitières, les vétérinaires canadiens sont appelés à effectuer l'évaluation des risques reliés à la biosécurité. L'objectif de cette étude était, par conséquent, de comprendre la perception qu'ont les vétérinaires de la biosécurité et de comparer cette perception entre les paires producteurs-vétérinaires. Des questionnaires ont été administrés à 106 producteurs québécois et à leurs vétérinaires (n = 82). Les réponses des paires producteurs-vétérinaires ont été comparées. Alors que la plupart des vétérinaires ont déclaré qu'il était facile de discuter de biosécurité avec leurs clients, la plupart des vétérinaires et des producteurs n'ont pas déclaré en avoir discuté dans l'année précédant l'étude. De plus, lorsque les producteurs ou les vétérinaires ont rapporté avoir discuté de sujets liés à la biosécurité, il n'y avait pas d'accord entre les paires. Les vétérinaires ont également mal évalué la façon dont leurs clients percevaient l'importance et l'utilité des mesures de biosécurité. Enfin, les vétérinaires ont indiqué qu'ils avaient les connaissances et la possibilité d'évaluer et de discuter de la biosécurité dans les exploitations laitières, mais manquaient de compétences pour évaluer les exploitations et communiquer leurs connaissances.(Traduit par Dr José Denis-Robichaud).

Herd-Level Mastitis-Associated Costs on Canadian Dairy Farms.

Mastitis imposes considerable and recurring economic losses on the dairy industry worldwide. The main objective of this study was to estimate herd-level costs incurred by expenditures and production losses associated with mastitis on Canadian dairy farms in 2015, based on producer reports. Previously, published mastitis economic frameworks were used to develop an economic model with the most important cost components. Components investigated were divided between clinical mastitis (CM), subclinical mastitis (SCM), and other costs components (i.e., preventive measures and product quality). A questionnaire was mailed to 374 dairy producers randomly selected from the (Canadian National Dairy Study 2015) to collect data on these costs components, and 145 dairy producers returned a completed questionnaire. For each herd, costs due to the different mastitis-related components were computed by applying the values reported by the dairy producer to the developed economic model. Then, for each herd, a proportion of the costs attributable to a specific component was computed by dividing absolute costs for this component by total herd mastitis-related costs. Median self-reported CM incidence was 19 cases/100 cow-year and mean self-reported bulk milk somatic cell count was 184,000 cells/mL. Most producers reported using post-milking teat disinfection (97%) and dry cow therapy (93%), and a substantial proportion of producers reported using pre-milking teat disinfection (79%) and wearing gloves during milking (77%). Mastitis costs were substantial (662 CAD per milking cow per year for a typical Canadian dairy farm), with a large portion of the costs (48%) being attributed to SCM, and 34 and 15% due to CM and implementation of preventive measures, respectively. For SCM, the two most important cost components were the subsequent milk yield reduction and culling (72 and 25% of SCM costs, respectively). For CM, first, second, and third most important cost components were culling (48% of CM costs), milk yield reduction following the CM events (34%), and discarded milk (11%), respectively. This study is the first since 1990 to investigate costs of mastitis in Canada. The model developed in the current study can be used to compute mastitis costs at the herd and national level in Canada.

Quantification of bovine immunoglobulin G using transmission and attenuated total reflectance infrared spectroscopy.

In this study, we evaluated and compared the performance of transmission and attenuated total reflectance (ATR) infrared (IR) spectroscopic methods (in combination with quantification algorithms previously developed using partial least squares regression) for the rapid measurement of bovine serum immunoglobulin G (IgG) concentration, and detection of failure of transfer of passive immunity (FTPI) in dairy calves. Serum samples (n = 200) were collected from Holstein calves 1-11 days of age. Serum IgG concentrations were measured by the reference method of radial immunodiffusion (RID) assay, transmission IR (TIR) and ATR-IR spectroscopy-based assays. The mean IgG concentration measured by RID was 17.22 g/L (SD ±9.60). The mean IgG concentrations predicted by TIR and ATR-IR spectroscopy methods were 15.60 g/L (SD ±8.15) and 15.94 g/L (SD ±8.66), respectively. RID IgG concentrations were positively correlated with IgG levels predicted by TIR (r = 0.94) and ATR-IR (r = 0.92). The correlation between 2 IR spectroscopic methods was 0.94. Using an IgG concentration <10 g/L as the cut-point for FTPI cases, the overall agreement between TIR and ATR-IR methods was 94%, with a corresponding kappa value of 0.84. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for identifying FTPI by TIR were 0.87, 0.97, 0.91, 0.95, and 0.94, respectively. Corresponding values for ATR-IR were 0.87, 0.95, 0.86, 0.95, and 0.93, respectively. Both TIR and ATR-IR spectroscopic approaches can be used for rapid quantification of IgG level in neonatal bovine serum and for diagnosis of FTPI in dairy calves.

A rapid field test for the measurement of bovine serum immunoglobulin G using attenuated total reflectance infrared spectroscopy.

BACKGROUND: Following the recent development of a new approach to quantitative analysis of IgG concentrations in bovine serum using transmission infrared spectroscopy, the potential to measure IgG levels using technology and a device better designed for field use was investigated. A method using attenuated total reflectance infrared (ATR) spectroscopy in combination with partial least squares (PLS) regression was developed to measure bovine serum IgG concentrations. ATR spectroscopy has a distinct ease-of-use advantage that may open the door to routine point-of-care testing. Serum samples were collected from calves and adult cows, tested by a reference RID method, and ATR spectra acquired. The spectra were linked to the RID-IgG concentrations and then randomly split into two sets: calibration and prediction. The calibration set was used to build a calibration model, while the prediction set was used to assess the predictive performance and accuracy of the final model. The procedure was repeated for various spectral data preprocessing approaches. RESULTS: For the prediction set, the Pearson's and concordance correlation coefficients between the IgG measured by RID and predicted by ATR spectroscopy were both 0.93. The Bland Altman plot revealed no obvious systematic bias between the two methods. ATR spectroscopy showed a sensitivity for detection of failure of transfer of passive immunity (FTPI) of 88 %, specificity of 100 % and accuracy of 94 % (with IgG <1000 mg/dL as the FTPI cut-off value). CONCLUSION: ATR spectroscopy in combination with multivariate data analysis shows potential as an alternative approach for rapid quantification of IgG concentrations in bovine serum and the diagnosis of FTPI in calves.

Measurement of serum immunoglobulin G in dairy cattle using Fourier-transform infrared spectroscopy: a reagent free approach.

Simple, rapid and cost-effective methods are sought for measuring immunoglobulin G (IgG) concentrations in bovine serum, which can be applied for diagnosis of failure of transfer of passive immunity (FTPI). The aim of the present study was to investigate the potential use of Fourier-transform infrared (FTIR) spectroscopy, with partial least squares (PLS) regression, to measure IgG concentrations in bovine serum. Serum samples collected from calves and adult cows were tested in parallel by radial immunodiffusion (RID) assay and FTIR spectroscopy. The sample IgG concentrations obtained by the RID method were linked to pre-processed spectra and divided into two sets: a combined set and a test set. The combined set was used for building a calibration model, while the test set was used to assess the predictive ability of the calibration model, resulting in a root mean squared error of prediction (RMSEP) of 307.5 mg/dL. The concordance correlations between the IgG measured by RID and predicted by FTIR spectroscopy were 0.96 and 0.93 for the combined and test data sets, respectively. Analysis of the data using the Bland-Altman method did not show any evidence of systematic bias between FTIR spectroscopy and RID methods for measurement of IgG. The clinical applicability of FTIR spectroscopy for diagnosis of FTPI was evaluated using the entire data set and showed a sensitivity of 0.91 and specificity of 0.96, using RID as the reference standard. The FTIR spectroscopy method, described in the present study, demonstrates potential as a rapid and reagent-free tool for quantification of IgG in bovine serum, as an aid to diagnosis of FTPI in calves.

Predicting the effect of anthelmintic treatment on milk production of dairy cattle in Canada using an Ostertagia ostertagi ELISA from individual milk samples.

Gastrointestinal nematodes, such as Ostertagia ostertagi and several species of Cooperia, are ubiquitous in temperate climates and have been shown to have detrimental effects on production in adult dairy cattle. A published meta-analysis demonstrated that overall, producers lose approximately 0.35 kg of milk per parasitized cow per day. Enzyme-linked immunosorbent assays (ELISAs) have the ability to quantify nematode infections in cattle, and thus, could be used to estimate the amount of milk production loss due to differing levels of parasitism at the individual cow level. ELISA results from individual cow milk samples were used to predict milk production response following a randomized anthelmintic treatment in a large field trial. To increase statistical power, the data collected from this field trial was pooled with data from two other published field trials to form an individual patient data meta-analysis (IPDMA). The ability to predict the effect of anthelmintic treatment on milk production depends on the level of parasitism quantified by an ELISA measuring milk antibodies against O. ostertagi, and reported as optical density ratios (ODRs). Therefore, the estimates from the interaction between ODR and treatment on milk production were used to determine how well the ODR predicted the response of the treatment. It was anticipated that the relationship between milk production and ODR was unlikely to be linear, so fractional polynomials were applied to the continuous ODR values. The interaction in the field trial showed a trend (p=0.138) toward a beneficial treatment effect when the individual ODR values, measured in late lactation and using Svanovir(®), were greater than 0.12. When individual data from two other similar studies were included in an IPDMA, the interaction terms became statistically significant (p=0.009) indicating that there is a beneficial treatment effect when ODR values are slightly elevated. A graph was used to demonstrate the treatment effect (the estimated difference of kg/cow/day of milk yield between the treated and placebo cows), with 95% confidence intervals, as the ODR values increase. It is important to note that the methods of quantifying the ODR values differed between the three studies in the IPDMA, therefore some caution should be used when using these final estimated values. However, the shape and magnitude of the treatment effects, as well as the other fixed model estimates, were very similar between the field trial and the IPDMA suggesting that any bias would likely be minimal.