Bovine leukemia virus (BLV) causes enzootic bovine leukosis and can lead to significant economic losses in dairy herds. Accurate estimation of within-herd prevalence is an essential step for effective continuous surveillance and control. The objectives of this study were: (1) to build a statistical model predicting within-herd BLV prevalence using Bulk Tank Milk (BTM) ELISA antibody titers, (2) to assess the temporal stability of this model over three years, and (3) to explore the relationship between mean individual cow antibody titers and BTM results. A convenience sample of 30 dairy herds in the Canadian Maritimes was studied. Three years of bi-monthly BTM samples were collected to measure the BTM ELISA antibody titers. Individual ELISA testing of cows contributing to BTM was performed annually for three years, permitting estimation of the true within-herd prevalence. Among the 30 herds, 1453 cows tested BLV-positive in Year 1, 899 in Year 2, and 760 in Year 3. Mean within-herd prevalence were 42 % (SD 24 %), 31 % (SD 20 %), and 29 % (SD 20 %) in Year 1, 2, and 3, respectively. Seven univariable linear regression models for true within-herd prevalence were built, with predictors consisting of single BTM results or averages from two or three rounds of BTM results in proximity to the time of individual ELISA testing. The model using the average of two BTM samples collected two months apart as a predictor prevalence in the herd was selected as the best model based on the highest R² = 0.91 and Predictive R² = 0.90. Model predictions showed strong agreement with observed within-herd prevalence in subsequent years (concordance correlation coefficients 0.94-0.98), indicating temporal stability. Mean individual cow antibody titers were strongly correlated with BTM antibody levels (r = 0.95). This study presents a practical, stable, and cost-effective approach to estimate and monitor BLV within-herd prevalence using BTM ELISA testing. The model can support surveillance programs and help guide herd-level BLV management decisions over time.

Bovine leukemia virus causes enzootic bovine leukosis, the most common neoplastic disease of dairy cattle worldwide. Infection is lifelong, with most cattle remaining asymptomatic, approximately one-third developing persistent lymphocytosis, and a small proportion progressing to lymphoma. The proviral load (PVL), measured as the number of provirus copies per estimated white blood cell, is an indicator of transmission risk and disease progression and can be used to identify animals that contribute most to virus spread in control programs. However, longitudinal data describing PVL dynamics at the individual cow level are limited. The objectives of this study were to quantify temporal changes in PVL in naturally infected dairy cows over 3 years and evaluate the implications for repeated PVL testing in BLV control programs. A total of 716 BLV-positive cows from 25 commercial dairy herds in the Canadian Maritime provinces (Prince Edward Island, Nova Scotia, and New Brunswick) were included. Cows underwent annual PVL testing using quantitative PCR and were categorized as high, moderate, low, or undetectable PVL. Temporal changes in PVL were evaluated using repeated measurements, and conversion between PVL categories was assessed over one- and 2-year intervals. BLV proviral load showed an overall temporal trend toward higher values, with corresponding shifts in PVL categories observed across initial classification groups and within individual animals. Of cows with an initial low-PVL, 12% progressed to high-PVL over the study period. Among cows initially classified as moderate-PVL, 53% transitioned to high-PVL. A subset of cows maintained undetectable-PVL despite confirmed BLV seropositivity. These findings indicate that the likelihood of PVL progression is influenced by the initial PVL category, with moderate-PVL cows representing the group at greatest risk of becoming highly infectious. The results have practical implications for BLV control programs in dairy herds. Repeated PVL testing of cows with moderate-PVL may help identify animals at increased risk of viral transmission and guide targeted culling or segregation decisions. In contrast, cows with low-PVL may require less frequent testing, and cows with persistently undetectable-PVL may not require repeated PVL monitoring. Tailoring PVL testing frequency according to initial PVL status may improve the efficiency of BLV control programs by prioritizing management of highly infectious animals and reducing herd-level virus transmission.

IntroductionBovine Leukemia Virus (BLV) prevalence remains high in dairy cattle in North America. Quantifying the proviral load (PVL) in BLV-positive cows can be used to control this disease in herds where BLV is prevalent by focusing culling of high PVL animals to reduce the risk of transmission. The impact of high BLV PVL on dairy cows’ performance is not well established. The objective of this study was to assess the effect of high PVL status on milk production, occurrence of subclinical ketosis or mastitis, or fertility in BLV-infected cows.MethodsTwenty-five herds from the three Maritime provinces in Atlantic Canada were enrolled in this study. BLV infected cows were first identified by individual milk or serum testing. A validated quantitative qPCR was used to quantify the PVL in cows with positive BLV antibody results. Parity, 305-day milk production, annual geometric average somatic cell count, fat-to-protein ratio in milk on the first test post-calving, days in milk at first service, and calving-to-conception interval were collected from DairyComp305 software. Two-level mixed multivariable regression models were used to assess the relationship between BLV PVL and milk production, subclinical mastitis and ketosis and reproduction performance.ResultsHigh PVL was strongly associated with reduced milk production (387 kg and 431 kg) and reproduction performance (calving-to-conception interval lengthened by 50 days and 49 days), and higher odds of subclinical mastitis (Odds ratio = 2.38 and 2.48), when compared to BLVpositive cows with a low PVL and BLV-negative cows, respectively.ConclusionThese results support implementing a control program to prioritize culling high PVL cows.

Ensuring high-quality colostrum for newborn calves is essential for their health and future productivity. We applied Bayesian finite mixture models to estimate optimal cutoff values and evaluate the diagnostic accuracy of 3 methods-radial immunodiffusion (RID) assay, transmission infrared (TIR) spectroscopy, and digital Brix (dBrix) refractometry-measured on a continuous scale for assessing bovine colostrum quality, using 591 colostrum samples from 42 Holstein dairy herds in Atlantic Canada. The mean and standard deviation of IgG concentrations for high-quality colostrum were 61.07 ± 39.8 g/L, 51.28 ± 27.38 g/L, and 24.32 ± 4.13% Brix for RID assay, TIR spectroscopy, and dBrix refractometry, respectively, compared with 19.93 ± 15.54 g/L, 7.78 ± 37.4 g/L, and 15.87 ± 3.45% Brix for low-quality samples. The prevalence of high-quality colostrum was estimated at 83% (95% credible interval [CrI]: 0.79-0.88). The dBrix refractometer demonstrated the highest discriminatory power, with an area under the curve (AUC) of 0.94 (95% CrI: 0.91-0.97), followed by RID assay (AUC: 0.92; 95% CrI: 0.88-0.96) and TIR spectroscopy (AUC: 0.82; 95% CrI: 0.76-0.88). Optimal cutoff values were determined using Youden's index: 34.15 g/L for RID assay (sensitivity [Se] = 0.86, specificity [Sp] = 0.83), 22.74 g/L for TIR spectroscopy (Se = 0.88, Sp = 0.66), and 19.62% Brix for dBrix refractometry (Se = 0.90, Sp = 0.85). Correlation between RID assay and TIR spectroscopy was stronger for high-quality colostrum samples (0.80; 95% CrI: 0.77-0.84) than for low-quality samples (0.36; 95% CrI: 0.16-0.55), indicating that these methods are not perfectly correlated and justifying the need for multiple diagnostic approaches. Among individual methods, dBrix refractometry showed the highest positive predictive value (PPV = 1.00), and all methods demonstrated moderate negative predictive values (NPV = 0.46-0.57). Combining methods in series interpretation increased PPV up to 1.00 when all 3 methods were used together, though with reduced NPV. Conversely, parallel interpretation substantially improved NPV, reaching 0.98 when all 3 methods were combined. By modeling continuous measurements instead of dichotomized test results, our analysis produced refined cutoff values for assessing colostrum quality. The findings indicate that existing thresholds remain largely adequate, offering only minor performance improvements, and emphasize the need to balance diagnostic refinements with their potential effects on calf management and passive immunity. Furthermore, our findings suggest that, although individual assessment methods offer valuable diagnostic information, combining multiple methods can optimize either Se or Sp, depending on the interpretation approach, thereby further enhancing the accuracy of colostrum quality evaluation.

Selecting and raising dairy animals that are more likely to reach their potential is a strategy to increase milk production efficiency and overall profitability. However, indicators are necessary for the early identification of animals that are less likely to perform well, allowing for their early culling and ensuring that resources are allocated to those with the highest potential. The objective of this study was to analyze the association between early-life animal health and performance with longevity, production, and profitability. After data cleaning, the following early-life measures (i.e., predictors) were available for 363 female calves born between June 2014 and November 2015 in eight dairy herds from New Brunswick, Canada (average: 45 calves/farm; SD: 26.1 calves/farm; median: 42 calves/farm; range: 15-95 calves/farm): birth weight, weaning weight, weaning age, weaning average daily gain (weaning ADG), immunoglobulin G (IgG) serum concentration, the occurrence of navel infection, diarrhea, and pneumonia, and if animals received antibiotic treatment between birth and weaning. Their subsequent length of life (LL), length of productive life (LPL), lifetime cumulative energy-corrected milk (ECM), and lifetime cumulative milk value (i.e., response variables) were provided by the Canadian dairy herd improvement agency. Bayesian Additive Regression Tree models were trained for each response variable using 5-fold cross-validation. Models were evaluated using the RMSE and R-2. The three most important predictors were identified using permutation, and the relationship between response variables and important predictors was assessed using accumulated local effect plots. The RMSE for LL, LPL, ECM, and milk value were 1.43 years, 1.37 years, 16 314.94 kg, and $CAD 11 525.68, respectively, whereas the R-2 values were 0.30, 0.25, 0.29, and 0.29, respectively, indicating a moderate relationship between predictors and response variables. Non-linear relationships were found between the response variables and important predictors. Animals born with low or high birth weights were associated with decreased LL, LPL, ECM, and milk value. The highest LL, LPL, and milk value was observed for calves weaned between 1.9 and 2.0 months old, followed by a decline for calves weaned at older ages. The lowest LL and ECM were associated with weaning ADG of 0.786 kg/day, while 0.787 kg/day was associated with the lowest LPL. Lastly, both ECM and milk value were highest when serum IgG values were 1 659 mg/dL. These findings provide valuable insights for optimizing early culling decisions and enhancing the productivity and profitability of dairy farms.

Objective The primary objective was to determine the youngest age group where bovine leukemia virus (BLV)-infected dairy animals were identified. The secondary objective was to investigate associations between age-specific management practices and BLV infection status of different age groups of dairy calves and heifers. Procedure For enrolled herds, BLV status was determined using blood samples from pre-weaned calves, weaned calves, and breeding-age heifers; and bulk tank milk from the adult herd. A questionnaire investigating age-specific management factors was administered for each herd. Ordinal logistic regression was performed to identify management factors associated with the youngest age range in which BLV was identified. Results Fifty-three dairy herds from the 4 provinces in Atlantic Canada were enrolled. Bovine leukemia virus was most commonly earliest identified in pre-weaned heifers (18 herds, 32.1%) and the adult herd (18 herds, 32.1%). Ordinal logistic regression revealed that BLV was first identified in older age groups more often than in younger age groups when herds regrouped weaned heifers at least once, when fly control was used for breeding-age heifers, when herds practiced foot trimming on breeding-age heifers, and when bred heifers were brought in. Conclusion Producers can use results to identify the youngest age group(s) in which BLV is identified and to tailor management strategies to prevent new infections.

Rates of congenital syphilis (CS)—when an infant contracts the disease during pregnancy or birth—are continuing to climb at an alarming rate in the United States. Although preventable, rates more than tripled between 2017 and 2021, with more than 2800 cases reported in 2021 alone. CS can cause stillbirth, infant death, or other serious and permanent complications including musculoskeletal defects (eg, impairments in the muscles, bones, and joints leading to temporary or lifelong limitations in functioning), vision and hearing problems, and developmental delays. An ASTHO technical package is a summary of a select group of related interventions that, taken together, help achieve and sustain improvements related to risk factors or health outcomes. ASTHO technical packages are based on programmatic subject matter experts' assessment of evidence-based interventions, expert recommendations, overviews of current activities, and a review of Centers for Disease Control and Prevention (CDC) and other federal funding guidance. They are not intended to be comprehensive and can be iterative. ASTHO's Congenital Syphilis Technical Package focuses on policy-level interventions that states and territories can pursue starting in pregnancy. ASTHO acknowledges other evidence-based or promising policy interventions that broadly address sexually transmitted disease (STI) prevention that are not reflected in this technical package. Furthermore, this technical package will be updated if updates to CDC's guidance on recommended syphilis screening for pregnant persons are available. Readers can stay current on these recommendations by accessing CDC Vital Signs (https://www.cdc.gov/vitalsigns/index.html).1 A summary of ASTHO's Congenital Syphilis Technical Package is outlined in the Table. TABLE - ASTHO Technical Package on Congenital Syphilis Objective Potential Indicators Mechanisms Levels of Influence Increase universal syphilis screening in pregnant persons28 Universal screening for syphilis at first prenatal visit Universal syphilis screening at 3 points of pregnancy care Review your jurisdiction's existing prenatal screening and disease reporting laws to determine if changes to the laws are required. Consult legal counsel to determine if you have direct authority to require universal syphilis screening at 3 points of pregnancy care. Determine if your jurisdiction's Medicaid program pays for syphilis screening 3× per pregnancy. If not, evaluate whether there are opportunities to change screening requirements and payment. Work with state medical licensing boards to develop provider education and awareness on universal screening. Determine feasibility of enforcement mechanisms, such as implementing fines or penalties for providers who do not screen pregnant people. Prenatal screening and disease reporting laws Legal counsel State policy makers State Medicaid partners and experts State professional licensure boards State medical and primary care associations State medical providers Optimize Medicaid eligibility, services, and alternative provider types to support pregnant people and their partners at risk for contracting syphilis5,11,28–33 Eligibility: Expanded Medicaid eligibility for family planning programs Expanded Medicaid postpartum coverage for up to 12 months Services: Comprehensive services for STI testing, treatment, and counseling Coverage of HRSN services Alternative providers: Expanded access to alternate provider types including CHWs and doulas Eligibility: Work with state Medicaid agency partners to amend state Medicaid plan through an SPA to expand Medicaid eligibility for family planning programs and expand postpartum coverage.34 Services: Work with state Medicaid agency partners to submit SPAs to ensure comprehensive coverage of STI testing, treatment, and counseling including, but not limited to, coverage of at-home testing kits. Work with state Medicaid agency partners to limit cost sharing and remove prior approval for STI testing. Work with state Medicaid agency partners to submit 1115 waiver for HRSN.35 Work with state Medicaid agency partners to inform managed care contract requirements to require Medicaid MCOs to provide HRSN.8 Providers: Work with state Medicaid agency partners to submit an SPA, 1115 waiver, or managed care requirement to authorize payment for or require use of CHWs.36 Work with state Medicaid agency partners to submit an SPA to cover doulas.12 State Medicaid agency partners and experts CMS Legal counsel State policy makers Incentivize providers to comply with universal syphilis screening requirements14,29,37–45 Quality measures: State Medicaid program uses Prenatal and Postpartum Care CMS Core Measure (NCQA, measure #1517) Incentivizes Prenatal and Postpartum Care CMS Core Measure (NCQA, measure #1517) Provider incentives: Medicaid MCOs offer provider incentives for complying with universal syphilis screening requirements Quality measures: Work with state Medicaid agency partners to implement use of Prenatal and Postpartum Care CMS Core Measure (NCQA, measure #1517). Work with state Medicaid agency partners to incentivize Prenatal and Postpartum Care CMS Core Measure (NCQA #1517). Create explicit details on the practice guidelines for STI screening during prenatal care as it relates to the NCQA prenatal care core measure. Borrow from HIV viral suppression incentive measure models to specifically target CS. Payment incentives: Work with Medicaid agency partners and MCOs to develop additional provider incentives for providers who comply with universal syphilis screening requirements. State Medicaid partners and experts CMS Private payers Establish an implementation plan for the quality strategy23 Established strategy for developing consumer education materials for individuals in Medicaid on CS risk Established strategy for providing education for Medicaid providers Consumer education: Work with state Medicaid agency partners to: a. Help facilitate Medicaid enrollment. b. Target Medicaid enrollment outreach to women in the first trimester of pregnancy. c. Ensure consumer education materials are available, clearly articulate risk, and are culturally competent. Provider education: Ensure changes to quality measure are communicated (eg, leverage Medicaid provider bulletins). Ensure changes to incentive payments are communicated and how to receive them. CMS State Medicaid partners and experts Private payers Cross-agency collaboration and governance State has cross-agency governance structure established to address CS Establish a corresponding joint Medicaid/public health quality committee related to syndemics (CS, HIV, etc) that also includes member representation is a critical action step to ensure implementation and support for the payment incentives/penalties and legislation are in place. Create a standing policy body that has a designated position for OB/GYN physician leaders to advise and engage in practice change. S/THAs could build relationships and engage with Medicaid quality committees to highlight public health data, policy, best practice, and support available to respond to the rise in cases. Private payers State Medicaid partners and experts State public health agencies State medical providers State professional licensure boards Increase access to care by removing barriers, addressing stigma, and addressing provider bias46 Increased universal syphilis screening in settings outside of prenatal care (eg, jails, safe syringe programs, emergency rooms, drug treatment programs) If applicable, removal of reporting requirements related to pregnant people who are experiencing substance use Review your jurisdiction's existing screening and disease reporting laws to determine if changes to the laws are required to promote increased syphilis screening outside of prenatal care. Review your jurisdiction's existing reporting laws to determine if removing reporting related to pregnant people who are experiencing substance use is required. Consult legal counsel to determine if you have direct authority to require it. Work with state medical licensing boards to develop education and provider awareness on stigma and provider bias. Assess and address barriers to practice to build an adequate perinatal workforce to provide women and community-centered obstetric care. Support or establish mechanisms for doula and community worker reimbursement. Enhance and expand home-visiting services to promote universal syphilis screening in pregnant persons. Ensure public health workforce receives training on structural racism and implicit bias and the role it plays in negative maternal and neonatal health outcomes. Screening and disease reporting laws Legal counsel State policymakers State Department of Corrections and local corrections and law enforcement partners Safe syringe programs Drug treatment programs Hospitals Doulas and CHWs CHW associations State home-visiting programs and federal counterparts State professional licensure boards State medical and primary care associations State medical providers Abbreviations: CHW, community health worker; CMS, Centers for Medicare & Medicaid Services; CS, congenital syphilis; HRSN, health-related social needs; MCO, managed care organization; NCQA, National Committee for Quality Assurance; OB/GYN, obstetrics and gynecology; SPA, State Plan Amendment; S/THAs, state and territorial health agencies; STI, sexually transmitted infection. Increase Universal Screenings for Pregnant Persons Testing pregnant people for syphilis at 3 points of pregnancy—first and third trimesters and at delivery—is an evidence-based approach to reduce CS. The American College of Obstetricians and Gynecologists and CDC currently recommend universal first-trimester screening and additional screening for those who are at risk or live in areas of high rates of syphilis. However, these screening recommendations rely on providers' knowledge of the epidemiology in their area and to take patient histories to accurately judge risk. In addition, jurisdictions may have other laws or recommendations that reflect variability in testing requirements. Jurisdictions can increase syphilis screening of pregnant people by modifying their laws to require screening at 3 points during pregnancy. They can do so through direct authority of state health officials, Medicaid, state medical licensing boards, and other enforcement mechanisms. How Public Health Can Leverage Medicaid to Reduce CS Rates Medicaid provides coverage for low-income adults2 nationwide and covers more than 40% of all births.3 Syphilis rates are nearly 6 times higher4 among women insured through Medicaid than among women insured through commercial insurance. Optimize Medicaid Eligibility, Services, and Providers for At-Risk Pregnant People and Their Partners States can expand eligibility for Medicaid Family Planning Programs,5 which provide family planning benefits and STI services to people who would not otherwise qualify. In most states, services are available for individuals up to 200% Federal Poverty Level (FPL). Some states (eg, Iowa6) are expanding eligibility beyond that threshold. In addition, implementing State Plan Amendments (SPAs) to expand Medicaid postpartum coverage7 can allow coverage of postpartum treatment of syphilis. States can work with Medicaid agency partners to ensure Medicaid services comprehensively cover STI testing, treatment, and counseling with minimal cost sharing. States can also submit 1115 waivers to cover unmet health-related social needs, or HRSN, services8 (eg, housing, nutrition, transportation) that exacerbate poor health outcomes and should be addressed in tandem with medical treatment. Furthermore, states can weigh in on Medicaid managed care organizations (MCOs) contract requirements (https://www.astho.org/topic/population-health-prevention/healthcare-access/medicaid/impacting-sdoh-through-managed-care-contracts) to ensure coverage of HRSN services. States can leverage alternative provider types, such as community health workers (CHWs), doulas, and perinatal case managers,9 to facilitate access to services, encourage first- and third-trimester STI screenings, and provide support services. Currently, 9 states and Washington, District of Columbia, reimburse doula services10 under Medicaid. CHWs are already providing services for people living with HIV infection11 and can perform a variety of roles, improving access to care for people with syphilis. They can help with care coordination, coaching, and providing social support and health education. State and territorial health officials (S/THAs) can work with their Medicaid agency partners to submit an SPA12 or 1115 waiver to cover CHWs, doulas, or perinatal case managers or create managed care requirements to require use of these provider types. Incentivize Providers to Comply With Universal Syphilis Screening Requirements S/THAs can work with Medicaid agency partners to adopt and incentivize the Prenatal and Postpartum Care CMS Core Measure13 (National Committee for Quality Assurance Measure #151714) as part of the state's quality strategy.15 Incentivizing the quality measure16 encourages providers to meet performance metrics through a financial incentive. Furthermore, states can update practice guidelines to encourage providers to conduct universal STI screenings during prenatal care visits, including syphilis testing in the first and third trimesters. S/THAs can work with their Medicaid agency partners and MCOs to develop additional provider incentives. For example, AmeriHealth Caritas—a Louisiana-based MCO—offers provider incentives17 for third-trimester syphilis testing. The performance is measured on the basis of the percentage of live deliveries that had at least one test for syphilis. Practices that score above the 55th percentile for third-trimester screenings are eligible for bonus payments. States can also partner with their Medicaid agency partners and incentivize consumers18 through MCOs. Several states offer incentive programs for pregnant persons who attend one or all prenatal appointments. For example, Kentucky19 offers gift cards and South Carolina20 offers items such as strollers or car seats. Establish an Implementation Plan for the Quality Strategy S/THAs can work with their Medicaid agency partners to develop consumer education materials, including information on how to enroll in Medicaid,21 covered services, provider availability, and how to reduce the risk of CS.22 Targeted enrollment outreach to pregnant persons in their first trimester is critical for early testing and treatment since being screened for syphilis is more likely23 if a person is enrolled in Medicaid earlier. S/THAs can also work with their Medicaid agency partners and MCOs to ensure Medicaid providers are aware of quality measure changes and how to leverage incentive payments by including information through communication materials including Medicaid provider bulletins and state quality strategies.24 Establish Cross-Agency Collaboration and Governance Structures A critical step in ensuring implementation of payment incentives and legislation is creating mechanisms for S/THAs and their state Medicaid agencies to better coordinate services and polices directed toward low-income individuals at risk for CS and other syndemic conditions. Strategies for cross-agency collaboration and governance could include the following: Establishing a joint Medicaid/public health quality committee related to syndemics (eg, CS and/or HIV infection). Creating a standing policy body that has a designated position for OB/GYN physician leaders to advise and engage in practice change. Building relationships and engaging with Medicaid quality committees to highlight public health data, policy, best practice, and support available to respond to the rise in cases. Remove Barriers to Care by Addressing Stigma and Provider Bias Removing barriers to screening and treatment and addressing stigma and implicit bias are critical to reducing CS rates. Structural racism and prejudice contribute to and reinforce disparities in maternal and neonatal morbidity and mortality, including rates of CS. To address stigma, policymakers must implement strategies25 that address systematic prejudice and discrimination including developing systems that have several points of entry for care, provide culturally competent training for the providers and perinatal workforce, and foster multisector referral relationships. In addition, leveraging the perinatal workforce, including doulas, can support pregnant and postpartum people in seeking and remaining in prenatal and postnatal care. Doulas act as advocates and educators26 for pregnant people and using them improves maternal and neonatal outcomes. To increase access to doulas, states should consider expanding doula coverage under Medicaid. Medicaid reimbursement of doula services—which are typically covered out-of-pocket—helps make their services available to low-income and underserved populations.27 Conclusion States and territories can address the rise in CS infections by focusing on policy-level interventions provided in ASTHO's Congenital Syphilis Technical Package. These evidence-informed practices focus primarily on pregnancy and provide recommendations for enhancing screening, optimizing Medicaid eligibility and services, establishing and implementing a quality strategy, incentivizing and educating providers, educating consumers, establishing and implementing cross-agency collaboration and governance, and increasing access to care.

Microbiota analyses are key to understanding the bacterial communities within dairy cattle, but the impact of different storage conditions on these analyses remains unclear. This study sought to examine the effects of freezing at -80°C immediately after collection, refrigeration at 4°C for three days and seven days and absolute ethanol preservation on the microbiota diversity of pooled fecal samples from dairy cattle. Examining 16S rRNA gene sequences, alpha (Shannon, Pielou evenness, observed features and Faith PD indices) and beta (Bray-Curtis, βw and Weighted UniFrac) diversity were assessed. The effects of storage conditions on these metrics were evaluated using linear mixed models and PERMANOVA, incorporating the farm as a random effect. Our findings reveal that 7d and E significantly altered the Shannon index, suggesting a change in community composition. Changes in Pielou evenness for 3d and 7d storage when compared to 0d were found, indicating a shift in species evenness. Ethanol preservation impacted both observed features and Faith PD indices. Storage conditions significantly influenced Bray-Curtis, βw, and Weighted UniFrac metrics, indicating changes in community structure. PERMANOVA analysis showed that these storage conditions significantly contributed to microbiota differences compared to immediate freezing. In conclusion, our results demonstrate that while refrigeration for three days had minimal impact, seven days of refrigeration and ethanol preservation significantly altered microbiota analyses. These findings highlight the importance of sample storage considerations in microbiota research.

Mid-infrared spectral (MIR) patterns of serum and synovial fluid (SF) are candidate biomarkers of osteoarthritis (OA). The impact of long-term storage on MIR spectral patterns was previously unknown. MIR spectra of canine serum (52 knee-OA, 49 control) and SF (51 knee-OA, 51 control) were obtained after short-term and long-term storage in −80 °C. Multilevel simultaneous component analysis and partial least squares discriminant analysis were used to evaluate the effect of time and compare the performance of predictive models for discriminating OA from controls. The median interval of storage between sample measurements was 5.7 years. Spectra obtained at two time points were significantly different (p < 0.0001); however, sample aging accounted for only 1.61% and 2.98% of the serum and SF profiles’ variability, respectively. Predictive models for discriminating serum of OA from controls for short-term storage showed 87.3 ± 3.7% sensitivity, 88.9 ± 2.4% specificity, and 88.1 ± 2.3% accuracy, while for long-term storage, they were 92.5 ± 2.6%, 97.1 ± 1.7%, and 94.8 ± 1.4%, respectively. Predictive models of short-term stored SF spectra had 97.3 ± 1.6% sensitivity, 89.4 ± 2.6% specificity, and 93.4 ± 1.6% accuracy, while for long-term storage they were 95.7 ± 2.1%, 95.7 ± 0.8%, and 95.8 ± 1.1%, respectively. Long-term storage of serum and SF resulted in significant differences in MIR spectral variables without significantly altering the performance of predictive algorithms for discriminating OA from controls.

Salmonellosis is one of the leading causes of gastrointestinal infections in humans. In Canada, it is estimated that approximately 87,500 cases of salmonellosis occur every year in humans, resulting in 17 deaths. In the United States, it is estimated that 26,500 hospitalizations and 420 deaths occur every year. In dairy cattle, infections caused by nontyphoidal Salmonella enterica can cause mild to severe disease, including enteritis, pneumonia, and septicemia. Our study objectives were to determine the proportion of fecal samples positive for Salmonella in dairy cattle in Canada and determine the resistance pattern of these isolates. We used data collected through the Canadian Dairy Network for Antimicrobial Stewardship and Resistance (CaDNetASR). Pooled fecal samples from pre-weaned calves, post-weaned heifers, lactating cows, and manure storage were cultured for Salmonella, and the isolates were identified using matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Antimicrobial susceptibilities were determined using the minimum inhibitory concentration test, and resistance interpretation was made according to the Clinical and Laboratory Standards Institute. A 2-level, multivariable logistic regression model was built to determine the probability of recovering Salmonella from a sample while accounting for province, year, and sample source. The proportion of farms with at least one positive sample were 12% (17/140), 19% (28/144), and 17% (24/144) for the sampling years 2019, 2020, and 2021, respectively. Out of the 113 Salmonella isolates, 23 different serovars were identified. The occurrence of Salmonella appeared to be clustered by farms and provinces. The most common serovars identified were Infantis (14%) and Typhimurium (14%). Overall, 21% (24/113) of the Salmonella isolates were resistant to at least one antimicrobial. Resistance to tetracycline was commonly observed (17%); however, very limited resistance to category I antimicrobials (categorization according to Health Canada that includes third-generation cephalosporins, fluoroquinolones, polymyxins, and carbapenems) was observed, with one isolate resistant to amoxicillin/clavulanic acid. The proportion of Salmonella isolates resistant to 2 and 3 antimicrobial classes was 3.5% and 8.8%, respectively. Our study provided valuable information on the proportion of fecal samples positive for Salmonella, the serovars identified, and associated resistance patterns across CaDNetASR herds, at regional and national levels.

Host-microbe dynamics are of increasing interest in marine research due to their role in host health and productivity. Changes in the shell microbiome of American lobsters have been associated with epizootic shell disease, a syndrome that is spreading northwards across the eastern U.S. and Canadian Atlantic coast. This study analyzed differences in alpha and beta diversity, as well as differentially abundant taxa, in the shell-associated bacterial community of apparently healthy lobsters from four lobster fishing areas (LFAs) in Atlantic Canada. Over 180 lobsters from New Brunswick, Nova Scotia and Prince Edward Island (PEI) were sampled during seven sampling events over four sampling months. The bacterial community was identified using novel PacBio long-read sequencing, while alpha and beta diversity parameters were analyzed using linear regression models and weighted UniFrac distances. The bacterial richness, diversity and evenness differed by sampling location, sampling month, and molt stage, but not by lobster sex or size, nor sampling depth. Similarly, based on LFA, sampling month, year and lobster molt stage, the shell microbiome differed in microbial community composition with up to 34 out of 162 taxa differing significantly in abundance between sampling groups. This large-scale microbial survey suggests that the shell microbial diversity of apparently healthy lobsters is influenced by spatial and temporal factors such as geographic location, as well as the length of time the carapace is exposed to the surrounding seawater.

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 objective of this cross-sectional study was to determine associations between calf management practices, the number of antimicrobial treatments, and antimicrobial resistance in pre-weaned heifers on Canadian dairy farms. A composite of 5 fecal samples from pre-weaned calves was collected from 142 dairy farms in 5 provinces and analyzed for phenotypic antimicrobial susceptibility with the microbroth dilution method. Questionnaires were used to capture herd characteristics and calf management practices used on the farm. Calf treatment records were collected during the farm visits. Escherichia coli was isolated from all 142 fecal samples with the highest resistance to tetracycline (41%), followed by sulfisoxazole (36%), streptomycin (32%), chloramphenicol (28%), ampicillin (16%), trimethoprim-sulfamethoxazole (15%), ceftriaxone (4.2%), cefoxitin (2.8%), amoxicillin-clavulanic acid (2.1%), ciprofloxacin (2.1%), nalidixic acid (2.1%), azithromycin (1.4%), and gentamicin (1.4%). Multidrug resistance was observed in 37% of E. coli isolates. Three-quarters of farms used fresh colostrum as the most common type of colostrum fed to calves. Colostrum quality was checked on 49% of farms, but the transfer of passive immunity was only checked on 32% of farms in the last 12 mo. Almost 70% of farms used straw or hay or a combination as the bedding material for calves. Among the 142 farms, a complete set of calf records were collected from 71 farms. In a multivariable logistic regression model, farms with ≥1.99 – 32.57 antimicrobial treatments/calf-year were 3.2 times more likely to have multidrug resistant E. coli in calf feces compared farms with <1.99 antimicrobial treatments/calf-year. Farms using hay or straw beddings were 5.1 times less likely to have multidrug resistant E. coli compared with those with other bedding materials including shavings or sawdust. Bedding management practices on farms may need to be investigated to reduce the potential impact on disseminating multidrug resistant bacteria.

Objective:To compare PCR and culture results for the detection of Streptococcus equi subspecies equi (S. equi).Animals:Respiratory tract samples (N = 158) from horses being tested for S. equi.Procedure:Bacterial culture was carried out on samples from which S. equi was detected by quantitative real-time PCR.Results:S. equi was isolated from 12 (7.6%) samples: 4/9 (44%) samples when the PCR cycle threshold (CT) was ≤ 30, 7/30 (23%) when the CT was 30.1 to 35, and 1/119 (0.8%) when the CT was 35.1 to 40. The highest CT sample from a sample that yielded a positive culture was 36.9. The optimal Youden's J value was at a CT of 34.2, the same value as determined by number needed to misdiagnose when the cost of a false negative is deemed to be either 5 or 10 × that of a false positive.Conclusions:Viable S. equi was only detected in a minority of quantitative PCR (qPCR) positive samples. A qPCR CT of 34.2 was a reasonable breakpoint for likelihood of the presence of culturable S. equi.Clinical relevance:Evaluation of CT values may be useful as a proxy to indicate the likelihood of cultivable S. equi being present and could be useful as part of risk assessments.

Antimicrobial resistance in pathogenic bacteria is one of the preeminent concerns for the future of global health. There is a dose-dependent relationship between antimicrobial use (AMU) and the prevalence of antimicrobial-resistant pathogens. As most AMU in Canada is related to animal agriculture, there is a need to reduce overall AMU, which could be accomplished through surveillance of AMU in animal agriculture, including the dairy industry. The objective of this study was to quantify AMU on dairy farms across Canada. This study had two parts: a description of data collected in 2019–2020, and a meta-analysis comparing this data to previous estimates of AMU in the Canadian dairy industry. The first included a garbage can audit (GCA) on 107 farms in four Canadian provinces (British Columbia, Alberta, Ontario, and Nova Scotia) in 2020; AMU data were converted to the dose-based metrics of defined course doses (DCD) and defined daily doses (DDD). Mixed-effect linear models were fit to determine the relationship between province and use of different classes of antimicrobials. On average, for every 100 animals on the farm, 117 DCD of antimicrobials were administered per year (IQR: 55, 158). These treatments amounted to 623 DDD / 100 animal-yr (IQR: 302, 677 DDD/100 animal-years). Penicillins were the most used class of antimicrobials, followed by first-and third-generation cephalosporins. Farms in Ontario used more third-generation cephalosporins than other provinces. The second part of this study compared AMU in 2020 to previously reported Canadian studies through a meta-analysis. A GCA was conducted in 2007–2008 in Alberta, Ontario, Québec, and the Maritime provinces (Prince Edward Island, New Brunswick and Nova Scotia); another GCA was conducted in Québec in 2018. Overall, AMU was lower in 2018–2020 than in 2007–2008, with the exception of third-generation cephalosporin use, which increased.

The shell microbial community of lobsters—a key factor in the development of epizootic shell disease (ESD)—is still insufficiently researched in Atlantic Canada and many knowledge gaps remain. This study aimed to establish a baseline description and analysis of the shell microbiome of apparently healthy lobsters from four locations in the region. More than 180 lobster shell swab samples were collected from New Brunswick, Nova Scotia and Prince Edward Island (PEI). PacBio long-read 16S rDNA sequencing and bioinformatic analyses in QIIME2 identified the shell-associated bacteria. The shell microbiome of healthy lobsters consisted mainly of the bacterial classes Gammaproteobacteria, Saprospiria, Verrucomicrobiae, Alphaproteobacteria, Flavobacteriia, Acidimicrobiia and Planctomycetia. The microbial composition differed regionally and seasonally, with some classes showing decreased or increased relative abundances in the PEI samples as well as in the winter and spring samples in Nova Scotia. The core shell microbiome included potentially pathogenic as well as beneficial bacterial taxa, of which some were present only in certain regions. Bacterial taxa that have previously been associated with ESD were present on healthy lobsters in Atlantic Canada, but their frequency differed by location, sampling time, and moult stage. This study indicated that geographical and seasonal factors influenced the shell microbiome of apparently healthy lobsters more than host factors such as sex, size, and moult stage. Our results provide valuable reference microbial data from lobsters in a disease-free state.

Antimicrobial resistance (AMR) in animals, including dairy cattle, is a significant concern for animal and public health worldwide. In this study, we used data collected through the Canadian Dairy Network for Antimicrobial Stewardship and Resistance (CaDNetASR) to: (1) describe the proportions of AMR in fecal E. coli, and (2) investigate the relationship between antimicrobial use (AMU) (intramammary and systemic routes, while ac-counting for confounding by other variables) and AMR/multidrug resistance (MDR - resistance to & GE; 3 antimi-crobial classes) in fecal E. coli from Canadian dairy farms. We hypothesized that an increase of the AMU was associated with an increase in AMR in E. coli isolates. A total of 140 dairy farms across five provinces in Canada were included in the study. Fecal samples from pre-weaned calves, post-weaned heifers, lactating cows, and farm manure storage were cultured, and E. coli isolates were identified using MALDI-TOF MS. The minimum inhibitory concentrations (MIC) to 14 antimicrobials were evaluated using a microbroth dilution methodology. AMU was quantified in Defined Course Dose (DCD -the dose for a standardized complete treatment course on a standard size animal) and converted to a rate indicator -DCD/100 animal-years. Of 1134 fecal samples collected, the proportion of samples positive for E. coli in 2019 and 2020 was 97.1% (544/560) and 94.4% (542/574), respectively. Overall, 24.5% (266/1086) of the E. coli isolates were resistant to at least one antimicrobial. Resistance towards tetracycline was commonly observed (20.7%), whereas resistance to third-generation cephalosporins, fluoroquinolones, and carbapenems was found in 2.2%, 1.4%, and 0.1% of E. coli isolates, respectively. E. coli isolates resistant to two or & GE; 3 antimicrobial classes (MDR) was 2.7% and 15%, respectively. Two multilevel models were built to explore risk factors associated with AMR with AMU being the main exposure. Systemic AMU was associated with increased E. coli resistance. For an increase in systemic AMU equivalent to its IQR, the odds of resistance to any antimicrobial in the model increased by 18%. Fecal samples from calves had higher odds of being resistant to any antimicrobial when compared to other production ages and farm manure storage. The samples collected in 2020 were less likely to be resistant when compared to samples collected in 2019. Compared to previous studies in dairy cattle in North America, AMR in E. coli was lower.

Campylobacteriosis is one of the most common zoonotic diseases in North America. As opposed to humans, animal infections caused by Campylobacter spp. are often asymptomatic. In this study, data collected through the Canadian Dairy Network for Antimicrobial Stewardship surveillance system were used to determine the proportion of Campylobacter spp. and antimicrobial resistant isolates recovered from dairy cattle herds. Additionally, the association of antimicrobial use (AMU) with fecal carriage and antimicrobial resistance (AMR) of Campylobacter spp. were investigated. Pooled fecal samples from 5 animals from each production phase (pre-weaned calves, post-weaned heifers, lactating cows), and a manure storage sample were collected from 140 dairy herds across Canada. Samples were cultured using selective media, and Campylobacter isolates were speciated using matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Antimicrobial susceptibilities were determined using the minimum inhibitory concentration test, and interpretation was made according to the Clinical and Laboratory Standards Institute. Two multilevel logistic regression models were used to investigate the association between the AMU with the isolation and antimicrobial resistance in Campylobacter spp. Of 560 samples, 63.8% were positive for Campylobacter spp., and 96% of the participating farms had at least one sample source (i.e., calves, heifers, lactating cows, or manure storage) positive for Campylobacter spp. Overall, 54.3% of the Campylobacter spp. isolates were resistant to at least one antimicrobial. Resistance to tetracycline was observed in 49.7% of the Campylobacter spp. isolates, followed by ciprofloxacin (19.9%) and nalidixic acid (19.3%). The proportion of multi-drug resistant (≥3 antimicrobial classes) Campylobacter spp. isolates was low (0.3%); however, 15.6% were resistant to two different classes of antimicrobials. Samples collected from lactating cows, heifers, and manure storage were more likely to be positive for Campylobacter spp. compared to calves. Total AMU was associated with a decreased probability of recovering Campylobacter spp. In addition, AMR to either tetracycline or ciprofloxacin had an interaction with antimicrobial use. The probability of resistance to tetracycline increased for each unit increase in the total AMU (Defined Course Dose/100 animal-years), while the probability of resistance to ciprofloxacin decreased. Campylobacter coli isolates were more likely to be resistant to ciprofloxacin and tetracycline when compared to C. jejuni. Our study demonstrated that Campylobacter spp. is widespread among Canadian dairy farms, and a higher proportion of resistance to tetracycline was identified. The total AMU was associated with increased resistance to tetracycline in Campylobacter spp. isolates; however, for ciprofloxacin the AMU was associated with decreased resistance.

he most recent provisional data released by the Centers for Disease Control and Prevention indicate that over 107 000 lives were lost to drug overdose from 2021 to 2022. 1 These high rates of overdose, continuing risks posed by fentanyl, and widening socioeconomic and racial disparities in overdose mortality are concerning. State and territorial health officials (S/THOs) have responded by bolstering comprehensive efforts that span prevention, data monitoring, harm reduction