Estimating the sensitivity and specificity of serum ELISA and pooled and individual fecal PCR for detecting Mycobacterium avium subspecies paratuberculosis in Canadian cow-calf herds using Bayesian latent class models

While Johne's disease (JD) is less common in beef than in dairy herds, consolidation is increasing transmission risk. Estimates of Mycobacterium avium spp. paratuberculosis (MAP) prevalence and test performance in cow-calf herds are needed to inform control programs. Objectives of this study included describing the prevalence of MAP in Canadian cow-calf herds and comparing the relative performance of a serum ELISA, pooled fecal PCR and individual fecal PCR using Bayesian latent class models, and to investigate factors associated with positive MAP tests. Blood and fecal samples (n = 3,171) were collected from 159 Canadian cow-calf herds. All samples were analyzed using serum ELISA and fecal PCR (pools of five samples) and a subset of 913 fecal samples were also tested with individual PCR. Based on latent class analysis, MAP prevalence was higher in eastern compared to western Canada for both animals {East, 3% [95% Credible Interval (CrI) 1–7%]; West, 1% [95% CrI 0.2–2%]} and herds [East, 15% (95% CrI 2–35%); West, 10% (95% CrI 1–26%), based on one or more positive results]. Sensitivity (Se) and specificity (Sp) for animal level individual PCR were 96% (95% CrI 80–100%) and 98% (95% CrI 96–100%), respectively followed by pooled PCR [Se = 54% (95% CrI 36–72%), Sp > 99.9% (95% CrI 99.8–100%)] and ELISA [Se = 36% (95% CrI 22–52%), Sp = 98% (95% CrI 96–99%)]. Based on 20 samples per herd, the herd level Se of ELISA was 79% (95% CrI 47–100%) (at least one positive sample) compared to 43% (95% CrI 14–94%) for pooled PCR. Herd-level Sp was 99% (95% CrI 96–100%) for pooled PCR and 90% (95% CrI 83–100%) for ELISA. Cows from herds with dairy cattle on farm and cows with symptoms of JD in the past 3 years were more likely to be MAP positive. Herds that had animals with JD symptoms in the previous 3 years and those with more breeding females were most likely to test positive for MAP. While serum ELISA can be effective for herd screening, PCR performed better for animal testing. Pooled PCR testing could be a less costly option; however, determining the most cost-effective approach will require further economic analysis

What is the efficacy of metaphylaxis using antibiotics for the prevention of Bovine Respiratory Disease in beef cattle?

Bovine respiratory disease complex is the most economically significant disease of feedlot cattle. Putative causal organisms include Mannheimia haemolytica, Pasteurella multocida, Histophilus somni and Mycoplasma bovis, bovine herpesvirus, bovine viral diarrhea virus, bovine respiratory syncytial virus, and parainfluenza type 3 virus. Although vaccination against the putative causal organisms is a frequently used approach to aid in the prevention of BRD, it is also common and legal for antibiotics to be used for metaphylaxis at the arrival of beef cattle at feedlots. With a more significant concern for prudent antibiotic use in the beef industry, it is essential for decision making with regards BRDC management to understand the efficacy of metaphylaxis as a preventive management practice for BRDC. Systematic reviews of randomized controlled trials yield the highest level of evidence for the efficacy of treatment under field conditions, and comparative efficacy can be examined using network meta-analysis for multiple comparisons. Establishing the efficacy of metaphylaxis for the prevention of BRDC will serve to improve decision makers’ ability to engage in effective stewardship of antibiotics

What is the efficacy of viral and bacterial vaccines in feedlot cattle to reduce bovine respiratory disease (BRD) and subsequent antibiotic use?

Bovine respiratory disease complex is the most economically significant disease of feedlot cattle[4]. Putative causal organisms include Mannheimia haemolytica, Pasteurella multocida, Histophilus somni and Mycoplasma bovis, bovine herpesvirus, bovine viral diarrhea virus, bovine respiratory syncytial virus, and parainfluenza type 3 virus[5]. Vaccination against the putative causal organisms is a frequently used approach to aid in the prevention of BRD. With a more significant concern for prudent antibiotic use in the beef industry, it is vital that decision making with regards BRDC management be based on an understanding of the efficacy of vaccination programs and management factors that might modify the efficacy of the preventive management practice[6, 7]. Systematic reviews of randomized controlled trials yield the highest level of evidence for the efficacy of treatment under field conditions, and comparative efficacy can be examined using network meta-analysis for multiple comparisons. Establishing the efficacy of monovalent and polyvalent vaccinations for the prevention of BRDC in feedlot cattle will serve to improve decision makers’ ability to engage in effective stewardship of antibiotics

Vaccine use in Canadian cow-calf herds and opportunities for improvement

Vaccinations are one of the most impactful tools available to cow-calf producers to control within herd disease and later, in feedlots. While vaccine use has been studied across Canada, inconsistent and variable regional data makes analysis and interpretation difficult. The objective of this study was to describe vaccination protocols and factors associated with vaccine use in Canadian cow-calf herds and define associations between vaccine use and productivity outcomes. Surveys describing vaccine use in 2020 were collected from 131 cow-calf herds (40 eastern, 91 western), recruited through a national beef cattle surveillance program. Ninety-two percent of cows and replacement heifers, and 72% of bulls were vaccinated with Infectious Bovine Rhinotracheitis (IBR), Bovine Viral Diarrhea Virus (BVDV), Parainfluenza3 Virus (PI3), and Bovine Respiratory Syncytial Virus (BRSV). At least half of cows and bulls were vaccinated for clostridial pathogens and cows and heifers for viral calf scours. Clostridial vaccines were significantly more likely to be used in western Canada compared to eastern Canada. While 92% of producers vaccinated suckling calves against IBR/BRSV/PI3, only 47% provided a second vaccine prior to weaning; 78% of calves were also vaccinated at least once for BVDV before weaning. Producers who vaccinated calves against IBR/BRSV/PI3 before 3 months of age provided a second dose prior to weaning more often than producers who administer the first IBR/BRSV/PI3 vaccine later. Vaccine use has increased across Canada, particularly in calves, prior to weaning. Relative to label recommendations for annual vaccination, clostridial vaccines were generally underutilized in cows and bulls, and by producers in eastern Canada as compared to western Canada. Opportunities also exist to improve adherence to label recommendations for the booster dose of scours vaccine when used in bred replacement heifers. Protocols including product choices, the timing and boosting of respiratory vaccines in nursing calves vary widely across herds. Use of intranasal vaccines in neonatal calves less than 2 weeks old has increased in western Canada compared to previous reports. There is a need to better understand how timing of vaccination in nursing calves contributes to effectiveness, for respiratory disease in nursing and weaned calves

Factors associated with antimicrobial resistant enterococci in Canadian beef cattle: A scoping review

IntroductionAntimicrobial resistance (AMR) is a global health concern, occurring when bacteria evolve to render antimicrobials no longer effective. Antimicrobials have important roles in beef production; however, the potential to introduce AMR to people through beef products is a concern. This scoping review identifies factors associated with changes in the prevalence of antimicrobial-resistant Enterococcus spp. applicable to the Canadian farm-to-fork beef continuum.MethodsFive databases (MEDLINE, BIOSIS, Web of Science, Embase, and CAB Abstracts) were searched for articles published from January 1984 to March 2022, using a priori inclusion criteria. Peer-reviewed articles were included if they met all the following criteria: written in English, applicable to the Canadian beef production context, primary research, in vivo research, describing an intervention or exposure, and specific to Enterococcus spp.ResultsOut of 804 screened articles, 26 were selected for inclusion. The included articles discussed 37 factors potentially associated with AMR in enterococci, with multiple articles discussing at least two of the same factors. Factors discussed included antimicrobial administration (n = 16), raised without antimicrobials (n = 6), metal supplementation (n = 4), probiotics supplementation (n = 3), pen environment (n = 2), essential oil supplementation (n = 1), grass feeding (n = 1), therapeutic versus subtherapeutic antimicrobial use (n = 1), feeding wet distiller grains with solubles (n = 1), nutritional supplementation (n = 1) and processing plant type (n = 1). Results were included irrespective of their quality of evidence.DiscussionComparability issues arising throughout the review process were related to data aggregation, hierarchical structures, study design, and inconsistent data reporting. Findings from articles were often temporally specific in that resistance was associated with AMR outcomes at sampling times closer to exposure compared to studies that sampled at longer intervals after exposure. Resistance was often nuanced to unique gene and phenotypic resistance patterns that varied with species of enterococci. Intrinsic resistance and interpretation of minimum inhibitory concentration varied greatly among enterococcal species, highlighting the importance of caution when comparing articles and generalizing findings.Systematic Review Registration[http://hdl.handle.net/1880/113592

Beef herd health and productivity and exposure to the petroleum industry in west-central Alberta

Intensive biological accounting methods were developed to measure the health and productivity of cow-calf herds surrounding a new sour gas processing plant. From the fall of 1991 through calving 1997, cow production records from all 7040 recorded bull contacts were examined from seven area cow-calf herds. Detailed information was also collected on other risk factors known to influence beef herd productivity. The median risks for non-pregnancy, abortion, calving late, stillbirth, and calf mortality for local herds did not differ from other published reports. There was no significant change in the risk of non-pregnancy, abortion, calving late, stillbirth, calf mortality, median calving date or crude weaning weight. Herd average age-adjusted weight for both male and female calves significantly improved. Total sulfation and H2S deposition data were used as markers for the complex mixture of compounds found in emissions from sour gas processing plants and sour flares. Cumulative exposure assessments were made from detailed records of individual animal movements between pastures. No consistent associations were found between either total sulfation or H2S deposition and productivity parameters across the three cow-calf production cycles examined. There were, however, five examples of associations between increasing exposure to total sulfation and decreased productivity in the 18 models examined for exposure beginning with first bull contact. The association between cow-calf productivity and cumulative animal proximity to petroleum field facilities and gas flared from oil and gas batteries was then examined. Increased risk of non-pregnancy was sometimes associated with exposure to one or more of the following facility types: sour flaring battery facilities, all battery flaring sites, active gas wells, and larger field facilities. The associations were not however, consistent among years or even among risk periods for the same year. Facility proximity and flaring were not associated with increased abortion risk. Volume of flared sour gas from battery sites was associated with increased risk of stillbirth. Finally, sour flaring was associated with increased calf mortality risk for the 1992-93 calf crop. Several examples of associations between exposure and increased productivity were also found in the analysis most of which involved either oil wells or all well sites

Factors associated with serum vitamin A and E concentrations in beef calves from Alberta and Saskatchewan and the relationship between vitamin concentrations and calf health outcomes

The study objectives were to identify factors associated with serum vitamin A and E concentrations in beef calvesThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

The role of socio-demographic factors in premature cervical cancer mortality in Colombia

Abstract Background While cervical cancer (CC) is an important cause of premature mortality in Colombia, the impact of socio-demographic factors on CC mortality in young women is not well understood. The primary objective of this study was to identify differences in CC mortality among Colombian women aged 20–49 years associated with education, type of health insurance, urban or rural and region of residence, and to determine whether differences in mortality associated with education or insurance varied by age. Methods Cervical cancer deaths for 2005–2013 and risk factors were obtained from the National Administrative Department of Statistics. Populations at risk were calculated from age-stratified population projections and the 2010 National and Demographic Health Survey. Negative binomial regression models, stratified by age, were used to examine associations between socio-demographic factors and mortality rates and whether the effects of education and health insurance varied by age. Multiple imputation was used to examine the importance of missing data. Results Differences of CC mortality were identified among women with limited to no education compared to highly educated women, with the largest disparity in the youngest age group (IRR 26.8, 95 % CI 6.65–108). Differences in mortality associated with health insurance also varied based on age group. Women with contributory and special health insurance had lower mortality rates than women with subsidised or no health insurance, except in the youngest age group. No differences were observed between women with subsidised and those with no insurance in any age group. Mortality rates were high among women who resided in urban areas and in the Atlantic, Central, Pacific, and Amazon-Orinoquía regions of Colombia. Missing values in the mortality database did not impact the findings from this study. Conclusions Limited education was most strongly associated with premature CC mortality in the youngest women. Subsidised insurance did not appear to provide significant protection against CC mortality when compared to not having insurance, suggesting the need to examine diagnostic and treatment services available under the subsidised insurance plan. Our results could be used to target interventions to optimise the impact of resources to prevent premature mortality due to CC in Colombia