Biosecurity adoption in Québec dairy farms: Results from a risk assessment questionnaire analyzed using conventional and unsupervised artificial intelligence methods.

This study documents the current state of biosecurity on dairy farms in Québec following the implementation of a mandatory biosecurity risk evaluation that was part of the proAction accreditation program developed by Dairy Farmers of Canada. Using a cross-sectional design, 3,825 risk assessment questionnaires completed between 2018 and 2021 were extracted from Vigil-Vet database, which is a software used by veterinarians for conducting the proAction risk assessment. Descriptive statistics were used to summarize the practices adopted by dairy producers. Additionally, multiple correspondence analysis was used to explore the association between the diseases of most concern and the adoption of biosecurity practices. Moreover, we used a hierarchical cluster analysis on principal components to identify distinct patterns of biosecurity practices among dairy producers. This analysis enabled the identification of typologies or clusters of farms based on the specific biosecurity practices they currently employ. The results of the descriptive statistics indicated that mastitis was the disease of most concern for most dairy farmers (40%). Moreover, given that only 10% of the 2,237 dairy farmers who acquired animals adhered to quarantine practices, there seems to be a need for improved implementation of biosecurity measures aimed at restricting the introduction of diseases when introducing new animals. Conversely, cleaning stalls and health equipment were adequately addressed by 95% and 86% of dairy producers, respectively. The multiple correspondence analysis indicated no significant association between the disease of most concern and the farm's biosecurity profile, except for respondents who identified digital dermatitis as their disease of most concern. Through the hierarchical cluster analysis, 3 clusters were identified among 3,581 farms: (1) Cluster 1 included farms with good management of sick animals; (2) Cluster 2 included farms with good management of young animals; and (3) Cluster 3 included farms with poor management of sick animals and young animals. Our study makes an important contribution by providing valuable insights into the biosecurity practices currently adopted on Québec dairy farms. It establishes a baseline for assessing progress in biosecurity practices adoption and serves as a reference point for future evaluations. In addition, these findings play a key role in monitoring the effectiveness of interventions aimed at improving biosecurity on dairy farms. By making use of this knowledge, stakeholders can make informed decisions that prioritize animal health, increase productivity, and ensure sustainability of the dairy industry.

Bayesian estimation of the diagnostic accuracy of a multiplex real-time PCR assay and bacteriological culture for 4 common bovine intramammary pathogens.

Bacteriological culture (BC) is the traditional method for intramammary infection diagnosis but lacks sensitivity and is time consuming. Multiplex real-time PCR (mr-PCR) enables testing the presence of several bacteria and reduces diagnosis time. Our objective was to estimate bacterial species-specific sensitivity (Se) and specificity of both BC and mr-PCR tests for detecting bacteria in milk samples from clinical mastitis cases and from apparently normal quarters, using a Bayesian latent class model. Milk samples from 1,014 clinical mastitis cases and 1,495 samples from apparently normal quarters were analyzed by BC and mr-PCR. Two positive culture definitions were used: ≥1 cfu/0.01 mL and ≥10 cfu/0.01 mL of the specified bacteria. The mr-PCR was designed to simultaneously detect Staphylococcus aureus, Streptococcus uberis, Escherichia coli, and Streptococcus agalactiae. The priors used in our Bayesian model were weakly informative, with BC priors using the best available error data. Results were compared with those obtained using uniform priors for mr-PCR to test robustness. Weak and uniform priors gave about the same posterior distributions except for Strep. uberis from normal quarters and Strep. agalactiae. Multiplex real-time PCR Se on milk from clinical mastitis were lower than mr-PCR Se on milk from normal quarters. Multiplex real-time PCR Se was higher than BC on milk from normal quarters. Multiplex real-time PCR Se was generally lower than BC on milk from clinical mastitis and it varied by clinical severity. The estimate specificities of detection for all pathogens were ≥99%, regardless of sample type. The effect of milk sample preservation before testing was evaluated and may have been a factor that affected our observed results. A significant association was observed between sample age and mr-PCR results leading to reduced detection of E. coli and Strep. agalactiae in nonclinical samples. Differences in sample age between conduct of BC and of mr-PCR did not concur with any apparent differences between Se estimates of the 2 tests. Further work should be done to extend these results to other PCR-based tests for detecting bacterial species in milk samples, for which presented results could be used as prior parameter distributions. Limits of sample handling and storage and the potential existence of substances in clinical case samples that may interfere with PCR reactions also are worth further investigation.

Effect of nonclinical Staphylococcus aureus or coagulase-negative staphylococci intramammary infection during the first month of lactation on somatic cell count and milk yield in heifers.

Coagulase-negative staphylococci (CNS) are the most prevalent cause of intramammary infections in heifers around calving, but Staphylococcus aureus should not be ignored because it is also prevalent, contagious, and more likely to persist into lactation. The objective of this study was to determine the effect of a subclinical infection caused by S. aureus or CNS diagnosed during the first month of lactation in heifers on SCC, milk production, and culling risk during the entire first lactation. Data were obtained from a cohort of 50 farms following a mastitis monitoring and control program and subscribing to the animal health record system (DS@HR) through the ambulatory clinic of the Faculté de médecine vétérinaire of the Université de Montréal (St-Hyacinthe, Québec, Canada). This program included routinely collecting a composite milk sample at each farm visit from all recently freshened heifers. A total of 2,273 Holstein heifers were examined. Among the 1,691 heifers meeting the full selection criteria, 90 (5%) were diagnosed with S. aureus, 168 (10%) were diagnosed with CNS, and 153 (9%) were negative (no pathogen isolated). Test-day natural logarithm somatic cell count (lnSCC) was modeled in a repeated measures linear regression model with herd as random effect. The model-adjusted mean lnSCC in S. aureus and CNS groups were significantly higher than in the culture-negative group from 40 to 300 d in milk. At the test-day level, lnSCC in S. aureus and CNS groups were on average 1.2 and 0.6 higher, respectively, than the culture-negative group. A similar model for milk yield showed that mean milk yield was not statistically different between culture groups from 40 to 300 d in milk. The presence of a S. aureus or CNS intramammary infections in the first month of lactation in heifers correlates with future increased SCC over the entire first lactation.

Clinical diagnoses in young offspring from eastern Québec multigenerational families densely affected by schizophrenia or bipolar disorder.

OBJECTIVE: The follow-up since 1989 of a large sample of multigenerational families of eastern Québec that are densely affected by schizophrenia (SZ) or bipolar disorder (BP) has permitted to look at the rates of DSM diagnoses in the young offspring of a SZ parent (HRSZ) and of a BP parent (HRBP) who had an extremely loaded family history. METHOD: The sample (average age of 17.5, SD 4.5) consisted of 54 high-risk offspring (HR) having one parent affected by a DSM-IV SZ or BP. The parents descended from 21 multigenerational families that constitute a quasi-total sample of such kindred in eastern Québec. The HRs were administered a lifetime best estimate DSM-IV diagnosis. RESULTS: We observed that the rates, the diversity of diagnoses, the high comorbidity, the severity and the age of onset of the clinical diagnoses tended to be similar with those already reported in the offspring of affected parents with a low familial loading. Although the sample size was small, HRSZ and HRBP also tended to show similarities in their clinical status. CONCLUSION: Overall, taking into account methodological limitations, the observation early in life of some shared characteristics among HRSZ and HRBP in terms of non-psychotic diagnosis may be congruent with the accumulating evidence that several phenotypic features are shared in adulthood by the two major psychoses.

Kinetics of plasma apolipoprotein C-III as a determinant of diet-induced changes in plasma triglyceride levels.

OBJECTIVE: To compare the effect of a high monounsaturated fatty acid (MUFA) diet and of a control low-fat diet consumed under ad libitum conditions on plasma apolipoprotein (apo) C-III metabolism. DESIGN: Randomized, two-arm parallel dietary trial. SETTING: Diets were prepared and consumed at the metabolic kitchen of the Department of Food Sciences and Nutrition, and laboratory analyses were performed at the Institute of Nutraceuticals and Functional Foods at Laval University. SUBJECTS AND INTERVENTIONS: Eighteen men were randomly assigned to either the high MUFA diet or the low-fat control diet, which they consumed for 6-7 weeks. Before and after the dietary intervention, subjects received a primed-constant infusion of [5,5,5-D(3)]-L-leucine for 12 h under constant feeding conditions for the determination of plasma apoC-III kinetics. RESULTS: The high-MUFA diet and the low-fat control diet had no significant impact on plasma apoC-III production rate (PR) or fractional catabolic rate. However, diet-induced variations in plasma apoCIII PR predicted the reduction in plasma triglycerides and apoC-III levels (r=0.85, P<0.01 and r=0.73, P<0.05, respectively) in the high MUFA group only. CONCLUSIONS: These results suggest that the hypotriglyceridemic effect of a high-MUFA diet may be attributable in part to a reduced hepatic production of apoC-III. SPONSORSHIP: This study was supported in part by an operating grant from the Canadian Institutes of Health Research (CIHR), and the Canada Research Chair in Nutrition and Cardiovascular Health (B Lamarche).

Visceral adipose tissue accumulation, secretory phospholipase A2-IIA and atherogenecity of LDL.

OBJECTIVE: The aim of the present study was to investigate the combined impact of visceral adipose tissue (VAT) and secretory group IIA phospholipase A(2) (sPLA(2)-IIA) concentrations on the atherogenicity of low-density lipoprotein (LDL) particles among men. SUBJECTS: Analyses were conducted in 74 mid-obese healthy men (age: (mean+/-s.d.) 37.9+/-11.7 years). METHODS: Plasma levels of sPLA(2)-IIA were measured with a commercial ELISA and VAT levels were assessed by computed tomography. Distinct subpopulations of LDL particles were characterized from whole plasma using nondenaturating 2-16% gradient gel electrophoresis. RESULTS: Data indicated that plasma sPLA(2)-IIA levels were approximately 29% (P=0.007) higher among men characterized by a higher accumulation of VAT (>142 vs < or =142 cm(2)). Men having high plasma sPLA(2)-IIA levels (> or =127.2 ng/dl, the median value), were characterized by higher levels of plasma cholesterol (C) and apolipoprotein (apo) B, LDL-C, LDL-apoB, oxidized LDL (OxLDL) and by smaller LDL particles compared to men with sPLA(2)-IIA<127.2 ng/dl. Multiple regression analyses showed that plasma triglycerides and sPLA(2)-IIA levels explained 22.7 and 11.8% of the variance in LDL peak particle size, respectively. Levels of VAT and of sPLA(2)-IIA were the strongest correlates of OxLDL levels explaining, respectively, 15.0 and 5.5% of their variability. CONCLUSION: Both VAT and sPLA(2)-IIA levels modulate the atherogenecity of LDL by accounting for the reduction in their size and their susceptibility to oxidation.