Canadian Dairy Network for Antimicrobial Stewardship and Resistance (CaDNetASR): An On-Farm Surveillance System

Canada has implemented on-farm antimicrobial resistance (AMR) surveillance systems for food-producing animals under the Canadian Integrated Program for Antimicrobial Resistance (CIPARS); however, dairy cattle have not been included in that program yet. The objective of this manuscript was to describe the development and implementation of the Canadian Dairy Network for Antimicrobial Stewardship and Resistance (CaDNetASR). An Expert Panel (EP) of researchers was created to lead the development of the dairy surveillance system. The EP initiated a draft document outlining the essential elements of the surveillance framework. This document was then circulated to a Steering Committee (SC), which provided recommendations used by the EP to finalize the framework. CaDNetASR has the following components: (1) a herd-level antimicrobial use quantification system; (2) annually administered risk factor questionnaires; and (3) methods for herd-level detection of AMR in three sentinel enteric pathogens (generic Escherichia coli, Campylobacter spp., and Salmonella spp.) recovered from pooled fecal samples collected from calves, heifers, cows, and the manure pit. A total of 144 dairy farms were recruited in five Canadian provinces (British-Columbia, Alberta, Ontario, Québec, and Nova-Scotia), with the help of local herd veterinarians and regional field workers, and in September 2019, the surveillance system was launched. 97.1 and 94.4% of samples were positive for E. coli, 63.8, and 49.1% of samples were positive for Campylobacter spp., and 5.0 and 7.7% of samples were positive for Salmonella spp., in 2019 and 2020, respectively. E. coli was equally distributed among all sample types. However, it was more likely that Campylobacter spp. were recovered from heifer and cow samples. On the other hand, it was more common to isolate Salmonella spp. from the manure pit compared to samples from calves, heifers, or cows. CaDNetASR will continue sampling until 2022 after which time this system will be integrated into CIPARS. CaDNetASR will provide online access to farmers and veterinarians interested in visualizing benchmarking metrics regarding AMU practices and their relationship to AMR and animal health in dairy herds. This will provide an opportunity to enhance antimicrobial stewardship practices on dairy farms in Canada.

Use of pooled serum samples to assess herd disease status using commercially available ELISAs

Pooled samples are used in veterinary and human medicine as a cost-effective approach to monitor disease prevalence. Nonetheless, there is limited information on the effect of pooling on test performance, and research is required to determine the appropriate number of samples which can be pooled. Therefore, this study aimed to evaluate the use of pooled serum samples as a herd-level surveillance tool for infectious production-limiting diseases: bovine viral diarrhoea (BVD), infectious bovine rhinotracheitis (IBR), enzootic bovine leukosis (EBL) and Neospora caninum (NC), by investigating the maximum number of samples one can pool to identify one positive animal, using commercial antibody-detection ELISAs. Four positive field standards (PFS), one for each disease, were prepared by pooling highly positive herd-level samples diagnosed using commercially available ELISA tests. These PFS were used to simulate 18 pooled samples ranging from undiluted PFS to a dilution representing 1 positive in 1,000 animals using phosphate-buffered saline as diluent. A 1:10 dilution of the PFS resulted in positive results for IBR, BVD and EBL. Moreover, for IBR and BVD, results were still positive at 1:100 and 1:30 dilutions, respectively. However, for NC, a lower dilution (8:10) was required for a seropositive result. This study indicates that, at herd-level, the use of pooled serum is a useful strategy for monitoring infectious diseases (BVD, IBR and EBL) but not NC, using readily available diagnostic assays.

Mobile Veterinary Clinic: an innovative approach to promote calf health

Background: Calf morbidity and mortality are of great concern for dairyman all over the world including Bangladesh. A mobile Veterinary Clinic (MVC) was established to identify the diseases associated with morbidity and mortality and provide veterinary services at farmers’ door step to promote calf health. Methods: A MVC was established and run from October 2011 to October 2014 to promote calf health. A total of 500 farmers from small and large holder private farms having at least two crossbred cattle were selected. A motorcycle and a mobile phone were provided to each research assistant (RA). The farmers were linked with RAs through mobile number. The ULO/VS were linked with the RA of the respective upazila for immediate treatment of the affected animal(s). The farms were under routine surveillance of the RA. In case of sickness or mortality, RA immediately contacted with ULO/VS and project coordinator/principal investigator at Bangladesh Agricultural University. Necessary advices were given by ULO/VS/consultants to solve the problem as required. Health cards were distributed to the selected farmers for recording the health status of cattle. Diseases were confirmed by clinical and laboratory methods. Farmers were trained on better calf health management. Early disease diagnosis and treatment, routine de-worming and vaccination of cows and calves were performed regularly. Results: Before implementing MVC services, the overall mortality at herd level was 11.5% which was 8.2% and 14.7% in Muktagacha and Shahjadpur respectively. The overall morbidity was 48.5% which was higher in Shahjadpur (57.94%) than Muktagacha (33.81%). The most common causes of calf mortality were pneumonia (66.2%), unknown (17.4%), adverse drug effect (5.3%), FMD (2.6%) and sudden death (2.4%). Due to MVC at farmers’ door step, the overall herd level mortality reduced significantly from 11.5 to 2.9% which were 8.2 to 2.3% in Muktagacha and 14.7 to 3.6% in Shahjadpur. Conclusion: Measures to control pneumonia and FMD in calves should be undertaken. The unknown etiology of mortality should be explored. Cautions should be taken before administering drugs in calves. As MVC was successful in reducing calf mortality, we recommend replicating in other parts of the country.

Seroprevalence of brucellosis and Q fever infections amongst pastoralists and their cattle herds in Sokoto State, Nigeria

Brucellosis and Q fever are neglected zoonoses of global health importance, with unknown true prevalence in occupationally vulnerable settings, partly due to misdiagnosis for other febrile conditions and poor access to primary health care. We examined the seroprevalence of these diseases and associated factors amongst pastoralists and their cattle in Sokoto State, a hub of cattle and pastoral populations in Nigeria. Serum samples randomly collected from 137 pastoralists and 366 cattle from 27 herds in three selected Local Government Areas (LGAs) in the state were analysed for antibodies to Brucella abortus using Rose Bengal Plate Test (RBT) and competitive Enzyme-Linked Immunosorbent Assay (cELISA) as well as antibodies to Coxiella burnetti using indirect ELISA. Consenting pastoralists’ knowledge, perception and practices about the diseases were assessed using a semi-structured questionnaire. Data were analysed using descriptive statistics and bivariate analysis at p ≤ 0.05 level of significance. Brucellosis adjusted individual seroprevalence were 0.83% (95%CI: 0.04–4.59%) and 0% among pastoralists; 2.28% (95%CI: 1.16–4.43%) and 5.70% (95%CI: 3.68–8.74%) in cattle by RBT and cELISA, respectively. Adjusted herd-level seroprevalence for brucellosis were 23.20% (95%CI: 11.07–42.54%) and 42.00% (95%CI: 25.27–61.11%) by RBT and cELISA, respectively. For Q fever, higher seroprevalence of 62.57% (95%CI: 54.04–70.46%) and 2.98% (95%CI: 1.57–5.58%) were recorded amongst the pastoralists and their cattle, respectively. with adjusted herd-level seroprevalence of 40.36% (95%CI: 22.57–63.17%). The LGAs of sampling were significantly (OR: 0.2; 95%CI: 0.02–1.00) associated with Q fever infection, though marginal. The majority of the pastoralists had poor knowledge, perception and practices towards the diseases. This is the first study establishing the presence of brucellosis and Q fever at the human-animal interface in Sokoto State, Nigeria. The pastoralists’ poor knowledge, perception and practices about these diseases are worrisome and are important factors for consideration in disease control.

Evaluation of Tail Lesions of Finishing Pigs at the Slaughterhouse: Associations With Herd-Level Observations

The prevalence of tail lesions evaluated at the slaughterhouse varies considerably between herds. These lesions result mainly from tail biting, a harmful behavior with multifactorial origin. This study sought to investigate if a batchwise inspection of tails at slaughterhouse could be a useful method to estimate the animal welfare situation in finishing pig herds, and if so, what type and detail of tail scoring such an inspection should utilize. We investigated the distribution of different types of tail lesions and how well their scoring at slaughterhouse was associated with the situation recorded on-farm by a veterinarian as part of routine herd health visits. We also wanted to determine if animal welfare-related herd-level parameters, recorded by herd veterinarians during herd health visits, are associated with tail scoring at the slaughterhouse. A total of 10,517 pigtails from 84 herds were scored for this study. Herd data were collected from the national health classification register for pig farms in Finland and also included annual herd production quality data collected by the slaughterhouse. The scores of the tails varied considerably between the herds. On average, 48.1% (sd = 19.3) of the tails with an average length of 30.4 cm (sd = 2.7) were fully intact, 37.3% (13.9) had healed (length = 26.4, sd = 5.1 cm), 12.4% (9.0) (length = 28.9, sd = 4.3 cm) had minor acute wounds, and 2.3% (2.1) (length = 24.2, sd = 6.0 cm) had major acute wounds. Proportions of different tail lesions at slaughterhouse were associated with or tended to be associated with the following herd-level parameters in regression models: use of wood as enrichment (p < 0.1), one health parameter (leg problems other than arthritis, p < 0.05), and long-term animal welfare estimate (annual mortality, p < 0.05). Detailed tail evaluation at the slaughterhouse shows potential in estimating the tail lesions and long-term welfare level on the farm. By recording only one type of tail condition (such as tails with major acute lesions) at the slaughterhouse, it is not possible to estimate the total tail lesion situation in the herds before slaughter. A more detailed scoring similar to the one used in this trial is recommended.

Animal Brucellosis: Seroprevalence, Isolation and Molecular Detection in Southern and Central Ethiopia

Background: Brucellosis is one of the most frequent contagious neglected bacterial diseases with serious veterinary and public health importance throughout the world. A cross-sectional study on animal brucellosis was conducted from October 2018 to July 2019 in southern and central Ethiopia with the objective of estimating seroprevalence and molecular detection. Blood samples were collected for serum extraction from a total of 4274 individual animals (cattle, small ruminants and camel) from 241 herds/flocks. Blood clots from seropositive animals were also tested for brucellosis via molecular techniques. Additionally, 13 vaginal swab samples were collected from animals with recent abortion history for bacterial isolation and molecular detection.Results: The extracted serum samples were tested using multispecies I-ELISA and the overall individual animal and herd level seroprevalence was 3.95% (169/4274) and 18.26% (44/241) respectively. The animal level seroprevalence at species level was 1.58%, 8.89%, 12.44% in bovine, small ruminants (sheep and goat) and camel, respectively. Herd level seroprevalence were 5.43%, 52.08%, 100% in bovine, small ruminant and camel, respectively. The animal and herd level seroprevalence of bovine from intensive and extensive systems was 1.1%, 2.87% and 9.2%, 50.00% respectively. Brucella species was isolated from 6/13 (46.15%) vaginal swab samples cultured on brucella selective agar, and shown to be B.melitensis using Real-Time PCR. All of the blood clots from seropositive animals were negative for the presence of Brucellaspp with PCR.Conclusions: In the regions sampled animals in all three categories – cattle, sheep/goats, and camels – mostly had low seroprevalence rates for brucellosis, without great differences from previous serosurveys done in Ethiopia. However, seropositivity for camels was higher than what has been reported previously. Also, there was a notable difference in this study in cattle seroprevalence when comparing extensive with intensive systems, with the extensive system being much higher.