Preventive veterinary medicine最新文献

Digital dermatitis (DD) is a bovine claw disease responsible for ulcerative lesions on the coronary band of the foot. It causes significant animal welfare and economic losses to the cattle industry. Early detection of DD can lead to prompt treatment and decrease lameness. Current detection and staging methods require a trained individual to evaluate the interdigital space on each foot for clinical signs of DD. Computer vision (CV), a type of artificial intelligence for image analysis, has demonstrated promising results on object detection tasks. However, farms require robust solutions that can be deployed in harsh conditions including dust, debris, humidity, precipitation, other equipment issues. The study aims to train, deploy, and benchmark DD detection models on edge devices. Images were collected from commercial dairy farms with the camera facing the interdigital space on the plantar surface of the foot. Images were scored for M-stages of DD by a trained investigator using the M-stage DD classification system. Models were trained to detect and score DD lesions and embedded on an edge device. The Tiny YOLOv4 model deployed on a CV specific integrated camera module connected to a single board computer achieved a mean average precision (mAP) of 0.895, an overall prediction accuracy of 0.873, and a Cohen’s kappa of 0.830 for agreement between the computer vision model and the trained investigator. The model reached a final inference speed of 40 frames per second (FPS) and ran stably without any interruptions. The CV model was able to detect DD lesions on an edge device with high performance and speed. The CV tool can be used for early detection and prompt treatment of DD in dairy cows. Real-time detection of DD on edge device will improve health outcomes, while simultaneously decreasing labor costs. We demonstrate that the deployed model can be a low-power and portable solution for real-time detection of DD on dairy farms. This result is a step towards applying CV algorithms to veterinary medicine and implementing real-time detection of health outcomes in precision farming.

The relative importance of maternal and horizontal transmission of small ruminant lentivirus (SRLV), the causative organism in maedi-visna, is poorly understood. Review of the literature shows that maternal transmission is inefficient, infecting only about 10–25 % of the lambs of infected ewes. Theory proves that maternal transmission alone cannot achieve the rates of transmission that would be required to start or maintain an outbreak. Maternal and horizontal transmission are additive in effect, and we use modelling to show that maternal transmission does not amplify or enhance prevalence in the presence of horizontal transmission. Taking steps to avoid maternal transmission by rearing lambs without infected maternal colostrum does have a role in producing a clean flock, but has no significance for the control of a disease outbreak if the conditions for horizontal transmission are present. Efforts to prevent disease by reducing the spread of SRLV must be focussed on minimising horizontal transmission.

Leptospirosis is an anthropozoonosis of economic and public health importance, caused by bacteria of the genus Leptospira. Horses are deemed important in its transmission chain due to their proximity to humans, and because the species is often asymptomatic, making these animals potential silent reservoirs. In this context, the objectives of this study were to determine the prevalence of seropositive horses for Leptospira spp., and to identify the presence of Leptospira spp. serogroups and antibody titers, the occurrence of areas with higher density of infection cases and demographic characteristics associated with seropositivity in the states of Paraíba (PB), Pernambuco (PE), Rio Grande do Norte (RN) and Ceará (CE), in the Northeast region of Brazil, during rainy (May and June) and dry (October and November) seasons from 2017 to 2019. Using the microscopic agglutination test (MAT), 1152 equine serum samples from 225 municipalities were analyzed. Anti-Leptospira antibodies were detected in 23.9 % (95 % CI= 21.4 – 26.3 %) of the samples in the three-year period, with a frequency of 30.4 % (95 % CI= 26.7 – 34.2 %) during the rainy period (with greater emphasis on the Ballum serogroup) and 17.4 % (95 % CI= 14.3 – 20.5 %) in the dry period (with greater emphasis on the Sejroe serogroup). Age of horses ≥ 6 years (6–10 years, 11–15 years and ≥ 16 years), rainy season, and animal belonging to Pernambuco state were factors with higher seropositivities. Regarding spatial distribution, a higher percentage of seropositive animals was observed in Pernambuco (P < 0.05), in interstate border areas, and large urban centers, with a spatial cluster detected in the dry season of 2018 with relative risk of 2.8 (P = 0.049) times higher in municipalities within the cluster. It is suggested that measures for controlling rodents and contact with wild animals in equine farming, both in rainy and dry periods, combined with care regarding the use of pastures shared with cattle and the adoption of immunoprophylaxis are important in preventing and controlling leptospirosis in horses in the Northeast region of Brazil.

Long-distance transport can cause stress to beef cattle impairing health and growth performances. This study aimed to deepen the knowledge of the effects of long-distance transport on young bulls’ metabolic profile to identify reliable blood parameters for monitoring their health and welfare. Eighty Charolais young bulls, transported for 12 hours to the final fattening unit, were weighed and blood sampled at three time intervals: before leaving the commingling centre (day −1), upon arrival at the fattening unit (day 0), and 7 days post-arrival (day 7). These bulls were part of a larger study aimed at testing whether the animals have some benefit from the supplementation of live yeast and selenium through slow-release rumen boluses that were administered to half of them before departure from France (‘Yeast’ vs ‘Control’ group). The effect of the supplementation on the parameters considered in this study was included in the statistical analysis to account for the structure of the experimental design. Transport affected the initial body weight of the animals, which dropped on day 0 and it was not fully recovered on day 7. Most plasma traits of protein, energy, hepato-muscle, and mineral profiles were affected by transport. Cortisol was also assessed and peaked at day 0. The footprint of the long-distance transport on bulls’ metabolic profile indicated a combination of stress, energy deficit, and muscle damage, with a certain degree of dehydration and liver impairment. Plasma traits measured on day −1 highlighted that stressful conditions and physiological responses of the bulls to recover homeostasis already started during the commingling phase before departure. No effect of supplementation was detected, except for higher selenium plasma level in Yeast bulls at day 7. Among blood parameters, non-esterified fatty acids, total protein, cortisol, glucose, and iron were those responsible for most of the variation in metabolic profile of bulls undergoing long journey. Therefore, these traits might be used as major biomarkers to assess stress in transported beef cattle, helping to identify critical situations for which proper mitigating actions should be taken. The outcomes of this study suggested that preventive measures against transport stress in beef cattle should start at the commingling of the animals in the collection centers, thus before departure.

Background

As low probability events, United States producers, value chain actors, and veterinary services (VS) have limited experience with identifying foreign animal disease (FAD), which can allow FADs to spread undetected. Point-of-care (POC) diagnostic testing may help reduce the time from detecting an initial suspect case to implementing actionable interventions compared to the current approach of only using laboratory diagnostic testing for disease diagnosis and confirmation. To evaluate the value of the reduced response time, we compare the associated costs between the two diagnostic approaches while accounting for the uncertainty surrounding the size of a FAD event.

Methods

We apply a state-contingent approach (SCA) to model the uncertainty surrounding a FAD through alternative events, where the event defines the scale of outbreak size and its duration. We apply this approach within a cost-benefit framework (CBA) to determine the economic value from the two testing investment strategies to help explain the policymaker’s response (and costs) to alternative FAD events while also considering the cost impacts on the producers from each event.

Results

Compared to the current laboratory strategy, a POC strategy that reduces response time by 0.5-days (swine, cattle scenarios) and 1.5-days (poultry scenario) may provide cost-saving to both producers and public response efforts. The benefit-cost analysis further suggests that despite the higher fixed costs to adopt the POC strategy, the swine and cattle sectors may benefit while the benefits may not be as pronounced in the poultry sector.

Discussion

POC testing that can reduce the time between detection and response during a FAD event may be a sound strategy for public expenditure and provide cost-savings for producers, especially when minimal fixed costs are incurred. However, to fully determine the value of POC testing, the consequences (costs) associated with potential actions if something goes wrong, (e.g. false positive results), should be considered in future studies.

Johne’s disease in cattle is a significant global animal health challenge. Johne’s disease is chronic, affecting the gastrointestinal tract of cattle and other ruminants and is caused by the bacteria Mycobacterium avium ssp. Paratuberculosis. Many countries have introduced schemes and programmes to try and control the spread of Johne’s disease, including the UK. Despite efforts to control it, however, Johne’s disease remains consistently ranked by UK producers as the top ranked disease negatively affecting productivity, indicating that schemes are not perceived to have solved the problem fully. Building on a global systematic review of the literature on barriers and solutions for Johne’s disease control on-farm, we conducted an empirical study with over 400 farmers and 150 veterinary professionals across the UK. The study used workshops and semi-structured interviews to understand better the challenges dairy farmers and veterinarians face in implementing on-farm Johne’s disease management schemes with the aim of identifying solutions. The study found that four main challenges are faced in the on-farm control of Johne’s – (1) Management of farmer expectations around Johne’s disease, with eradication near impossible, (2) Issues regarding space for segregation and the related economics of control (3) A ‘free-riding’ problem which can be influenced by the voluntary nature of control plans and (4) Challenges in vet-farmer communication, including levels of knowledge. Our findings have relevance for the control of Johne’s disease in the UK and other countries, including for regions with voluntary and compulsory control programmes.

Foot-and-mouth disease (FMD) is an ailment that causes serious damage to the productive chain, and its control through vaccination is of utmost importance for its eradication. Brazil initiated the National Foot-and-Mouth Disease Surveillance Program (PNEFA) with the aim of making the country FMD-free by 2026. As part of the program, notifications of vesicular lesions became mandatory for the Official Veterinary Service (OVS), which is responsible for verifying them. Due to its size, border areas with countries that do not have FMD-free status pose a risk to Brazil and require greater attention. This study described the profile of notifications of suspected outbreaks of vesicular syndrome in Brazil and analyzed the performance of the surveillance system. The results showed 7134 registered notifications of suspected vesicular syndrome outbreaks from 2018 to 2022, with 2022 having the highest number (n = 2343 or 32.85 %). The species that generated the most notifications were swine (90.99 %), cattle and buffaloes (7.54 %), goats and sheep (1.44 %), and others (0.03 %). The sources of notification were "Veterinary medicine professionals" (61.82 %), "Owners or employees" (13.66 %), "Third parties" (8.90 %), "OVS" (7.20 %), and "others" (2.66 %). 41.69 % of notifications originated from non-border municipalities, and 58.32 % from border areas. Only the state of Paraná account for 51.73 % of the total notifications. This state also accounted for 66.70 % of the 32.47 % of notifications with a final diagnosis of "absence of clinically compatible signs or susceptible animals", indicating a certain lack of knowledge in the area, leading to unnecessary notifications and system overload. The performance of the OVS was evaluated based on the service response time from notification registration trough Logistic and Negative binomial regressions. A total of 27.83 % of notifications did not meet the Brazilian legally specified time, and the zone related to the state of Parana needs improvements in performance. The presence and peaks of Senecavirus A cases may have influenced an increased number of swine notifications and led to a decrease in OVS response time. The results demonstrate better performance of surveillance in border areas. Given the vast territory of Brazil, it is not expected that 100 % of responses occur within the legal timeframe, however, the performance of the surveillance system proved to be adequate, with 86 % complied to the legislation. The performance indicators could be used as a monitoring tool, along with indicators to demonstrate system overload. Continued education actions are crucial for strengthening PNEFA.

Gonadectomy in dogs is associated with changes in risks of a variety of non-infectious health conditions, but few studies have examined its effects on infectious disease outcomes. The objectives of our study were to estimate the causal effect of gonadectomy on the incidence rate of babesiosis diagnosis, and on the risk of severe babesiosis in diagnosed cases, in dogs 6 months and older seen at a veterinary academic hospital in South Africa from 2013 through 2020. To estimate the effect of gonadectomy on the incidence rate of babesiosis diagnosis in dogs, we conducted a case-control study with incidence density sampling of dogs seen through the hospital’s primary care service, adjusting for sex, age, breed category and weight. We identified 811 cases and selected 3244 time-matched controls. To estimate the effect of gonadectomy on disease severity in dogs with babesiosis, we conducted a retrospective cohort study among all dogs with a diagnosis of babesiosis (n=923), including these 811 cases and a further 112 referred to the hospital, also adjusting for sex, age, breed category and weight. Gonadectomy substantially reduced the incidence rate of babesiosis (total effect incidence rate ratio [IRR] 0.5; 95 % confidence interval [CI] 0.41–0.60) and the risk of severe babesiosis among diagnosed dogs (total effect risk ratio [RR] 0.72; 95 % CI 0.60–0.86). Tipping point sensitivity analysis shows that these effect estimates are robust to unmeasured confounding bias. There was no evidence for modification of the effect of gonadectomy by sex, with effect estimates qualitatively similar for males and females for both outcomes. Compared to females, males had a higher incidence rate of babesiosis (IRR 1.74; 95 % CI 1.49–2.04) and a higher risk of severe disease (RR 1.12; 95 % CI 0.98–1.28). In conclusion, our study shows a robust protective effect of gonadectomy on the incidence and severity of babesiosis in both male and female dogs 6 months of age and older, and contributes important evidence to the debate on the overall risks and benefits of gonadectomy to dogs in this population.

To assess and enhance the application of biosecurity measures in poultry farming, an objective measurement tool (Biocheck.UGent™) was already available for broiler and layer. This study describes the development, validation and application of a risk-based weighted scoring tool for breeder, turkey, duck, free-range layer and free-range broiler production. In collaboration with an expert panel (n= 38), five different questionnaires were developed, following the format of the existing Biocheck.UGent scoring tools. Weights were attributed to external (7–9 subcategories) and internal (3–4 subcategories) biosecurity categories, as well as to the corresponding individual questions within each subcategory. The biosecurity measures were prioritized and weighed based on their relative importance in preventing disease transmission. Upon completion of the questionnaire, and upload of all answers to the Biocheck.UGent website, the algorithm generates a biosecurity score varying between ‘’0’’ which equals the total absence of any biosecurity measure up to ‘’100’’ which refers to full application of all biosecurity measures. The final scoring systems are available online (https://biocheckgent.com/en) for free and have been used to assess biosecurity in 70 breeders, 100 turkeys, 23 ducks, 16 free-range broilers, and 15 free-range layer farms originating from 12 countries so far. On average, the overall biosecurity score (mean ± std. dev) was 78 ± 7 % for breeders, 73 ± 11 % for turkeys, 71 ± 8 % for ducks, 73 ± 8 % for free-range layers and 70 ± 13 % for free-range broilers. There were significant differences (p < 0.05) in biosecurity (both at the overall and subcategory levels) across different poultry types. The overall farm biosecurity score for breeders was significantly higher than that for turkey (p <.001) and duck production (p = 0.001). External biosecurity levels were highest in breeders in comparison to turkeys (p < 0.001), ducks (p = 0.008) and broiler free-range (p = 0.005). There was a notable difference in internal biosecurity levels between duck and turkey (p = 0.041) production as well. The study contributed to the poultry biosecurity database which allows benchmarking of the biosecurity levels of the users’ farm results to national or international averages, indicating room for improvement and aiding to motivate stakeholders to enhance their biosecurity levels.

Bluetongue disease is an infectious disease transmitted by Culicoides as vectors, mainly infecting ruminants. Because ruminants play an important role in animal husbandry in China, the outbreak of bluetongue disease can cause serious economic losses. Maxent model was applied to predict the distribution of bluetongue in China based on the data derived from domestic and foreign academic literature databases including CNKI, Wanfang Database, PubMed, Web of Science and Google Scholar. The results showed that annual mean temperature (BIO1), precipitation in driest month (BIO14), sheep density (SD) and altitude (Elev) were the relevant variables of bioclimatic suitable zones for bluetongue disease. Precipitation in wettest month (BIO13), BIO1, BIO14, Elev were the main variables affecting the habitat of the bluetongue vector Culicoides. The most suitable climate for bluetongue infection occurs in southern China, central China and parts of Xinjiang. The suitable living areas of Culicoides are mainly located in southern, central and eastern China, and the overlap of the two suitable areas is high. The study suggested that southern, central, and eastern China are high-risk areas for bluetongue due to the significant overlap of suitable habitats for both the disease and its vector. Implementing effective surveillance and targeted control strategies in these regions is crucial for mitigating the impact of bluetongue disease.