Dairy farmers’ reasons for participation in the Danish control programme on bovine paratuberculosis

Prevalence of paratuberculosis in cattle in China: A systematic review and meta-analysis

Bovine paratuberculosis is a chronic infectious disease caused by Mycobacterium avium subspecies paratuberculosis (MAP). Here, a systematic literature review was conducted to investigate the bovine paratuberculosis distribution and associated risk factors in China before 2022. The databases CNKI, VIP, WanFang, PubMed, and ScienceDirect were used to search for articles. The random effect model of the "Meta" package of "R" software was used, and the Arcsine transformation was chosen for the rate conversion analysis. To reveal the factors that led to research heterogeneity, the research data were used for subgroup analysis and univariate meta-regression analysis. Among the 1238 identified articles, 54 met the eligibility criteria. Based on data obtained from the selected articles, the combined positive rate of bovine paratuberculosis was 6.95% in China. In the sampling year subgroup, the positive rate of bovine paratuberculosis before 2013 was 4.94%, which was lower than in other time periods. In the sampling season subgroup, the highest positive rate of bovine paratuberculosis in cattle was 14.60% in the autumn. Furthermore, in the detection method subgroup, the highest positive rate of bovine paratuberculosis was 7.21%, which was detected by using ELISA. In the age subgroup, the positive rate of bovine paratuberculosis was 17.47% in cattle > 12 months old, significantly higher than other age subgroups. The highest positive rate of bovine paratuberculosis was 11.35% for female cattle in the gender subgroup, while in the geographic region subgroup, the highest positive rate was 8.12% for East China, which was significantly higher than in other regions. The highest positive rate of bovine paratuberculosis was for dairy cattle (8.00%), and the highest positive rate by rearing method was 11.03% for non-scale farming. The effects of different geographical and climatic factors on the positive rate of bovine paratuberculosis were evaluated. In summary, we recommend focusing on screening cattle infected with MAP in warm and humid areas.

Factors that influence dairy farmers' decisions to implement Johne's Disease control practices: A systematic review

Johne's Disease (JD) is an infectious ruminant disease that can cause economic loss for famers through reduced milk yields and infertility and has negative implications for animal welfare. JD is endemic in the dairy populations of many countries and there has been significant effort by governments and industry to try and control it. However, these efforts have had limited success. Many studies look at individual control programmes or the adoption of Johne's control measures; however a wider perspective on what drives farmer participation Johne's control does not currently exist. This study seeks to fill this gap by conducting a systematic review informed by the PRISMA statement. The results suggest that psychological factors such as participation fatigue, cognitive dissidence over animal welfare and not having first-hand experience of the disease act as barriers to Johne's control. To better promote Johne's control, this review emphasises that control programmes need to engage farmers, advisers, and supply chain actors in their design and delivery of control programmes to account for differing attitudes and levels of knowledge.

Identification of different attitudes towards paratuberculosis control using cluster analysis applied on data from an anonymous survey among German cattle farmers

Background

Paratuberculosis is a common disease in ruminants, causing economic losses in livestock farming, and a relationship between the exposure to its causative agent Mycobacterium avium subsp. paratuberculosis, and Crohn’s disease in humans is discussed. Despite this, only a minority of cattle farmers have enroled in voluntary control programmes in most countries. Therefore, this study aimed at investigating the farmer’s opinion on paratuberculosis and their motivations to participate in a control programme. The objective was to identify different groups among farmers regarding their motivation and thereby contribute to a better understanding of farmers’ attitudes towards paratuberculosis control.

Results

Two hundred twenty-five farmers responded to questionnaires that were distributed among cattle farmers in Saxony and Thuringia, federal states of Germany, together with boot-swab sampling sets for a free and anonymous herd-level paratuberculosis test. Among them, dairy herds and large herds were overrepresented. A hierarchical cluster analysis of the farmers’ answers resulted in four groups that we tagged as ‘informed sceptics’, ‘deniers’, ‘affected supporters’ and ‘free supporters’. In all groups, the majority considered paratuberculosis a threat to the public image of cattle farmers. Nearly all participants wanted to know the paratuberculosis herd status of purchased cattle. In contrast to the supporters, the informed sceptics and the deniers did not consider paratuberculosis a dangerous epizootic disease and would not welcome a mandatory control programme. The deniers and the affected supporters, but not the informed sceptics and the free supporters, assumed that their herd is affected by paratuberculosis. Unlike the deniers, all other groups would enrol in a control programme if the pathogen would have been found in their herd. Protecting future profitability and improving animal health were the two most important motivations to control paratuberculosis in all groups followed by aspects related to the marketing of breeding cattle. Most frequently, the costs and the assumed inaccuracy of diagnostics tests were mentioned as obstacles that hamper programme enrolment.

Conclusions

Significantly different attitudes of farmers regarding paratuberculosis control were identified. Therefore, tailored rather than uniform communication strategies are required to enhance participation in voluntary paratuberculosis control programmes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13620-021-00204-3.

Narrative Review Comparing Principles and Instruments Used in Three Active Surveillance and Control Programmes for Non-EU-regulated Diseases in the Danish Cattle Population

The objective of this paper is to provide a comparative review of three active surveillance and control programmes in the Danish cattle sector to highlight important differences for decision makers to develop successful programmes. The focus is on differences in purpose, principles, design and instruments applied to achieve the goals stated for each programme for bovine viral diarrhoea (BVDV), paratuberculosis and Salmonella Dublin. The purposes of the programmes are to reduce economic consequences and improve animal welfare, and for S. Dublin also to prevent zoonotic risk, with varying importance as motivation for the programmes over time. The targets of the BVDV and S. Dublin programmes have been to eradicate the diseases from the Danish cattle population. This goal was successfully reached for BVDV in 2006 where the programme was changed to a surveillance programme after 12 years with an active control programme. The S. Dublin dairy herd-level prevalence decreased from 25% in 2003 to 6% in 2015, just before the milk quota system was abandoned. Over the last 5 years, the prevalence has increased to 8–9% test-positive dairy herds. It is mandatory to participate, and frequent updates of legislative orders were used over two decades as critical instruments in those two programmes. In contrast, participation in the paratuberculosis programme is voluntary and the goals are to promote participation and reduce the prevalence and economic and welfare consequences of the disease. The daily administration of all three programmes is carried out by the major farmers' organisation, who organise surveillance, IT-solutions and other control tools, projects and communication in collaboration with researchers from the universities, laboratories and, for BVDV and S. Dublin, the veterinary authorities. Differences among the programme designs and instruments are mainly due to the environmental component of paratuberculosis and S. Dublin, as the bacteria able to survive for extended periods outside the host. This extra diffuse source of infection increases the demand for persistent and daily hygiene and management efforts. The lower test sensitivities (than for BVDV) lead to a requirement to perform repeated testing of herds and animals over longer time periods calling for withstanding motivation among farmers.

Pilot implementation of a newly developed bovine leukemia virus control program on 11 Alberta dairy farms

We developed a custom bovine leukemia virus (BLV) control program for the Alberta dairy industry, consisting of a risk assessment and a comprehensive list of best management practices (BMP) aimed at prevention of BLV transmission between cattle. This control program was implemented on 11 farms for approximately 1 yr. Blood samples were collected from all cattle ≥12 mo old, and serum was tested with a commercial ELISA. Risk assessments were performed on each farm, risk-connected on-farm management was identified, and management changes expected to prevent transmission of BLV between cattle were suggested by the first author and agreed upon with each farmer. Throughout the following year, all participating farmers were visited multiple times to identify and overcome barriers to implementation and to monitor progress. After approximately 1 yr of implementing BLV control, all cattle ≥12 mo old on farm with a negative or no previous test result were sampled, and the within-herd prevalence was determined. The median number of cattle on farm that were ≥12 mo was 195 (range 110-524). The initial prevalence averaged 39% (13-66%). On average, 5 BMP (3-7) were suggested to each farmer. On average, 4 BMP (1-7) were implemented. At the second sampling, the average within-herd prevalence of all animals that tested positive (including the previous sampling) was 36% (12-62%). Eight farms reduced their within-herd BLV prevalence, within-herd prevalence stayed constant on 1 farm, and it increased on 1 farm. The remaining farm terminated their participation before the second sampling. The number of seroconversions per farm ranged from 3 to 109, highlighting the success of some producers to minimize new infections. The risk assessment was proven to be a valuable tool to identify flaws in on-farm management, although risk assessment score was unrelated to the within-herd BLV prevalence. Finally, it appeared that implementation of BMP aimed at prevention of BLV transmission between cattle could reduce within-herd BLV prevalence when farmers committed to their implementation.

"They've got to be testing and doing something about it": Farmer and veterinarian views on drivers for Johne's disease control in dairy herds in England

There needs to be an understanding of the reasons why key stakeholders engage in disease control efforts if disease is to be successfully and sustainably controlled. It is increasingly recognised within veterinary epidemiology and policy making in animal health that these 'people factors' are important influences on the success or otherwise of animal disease control programmes. Research methodologies adopted from the social sciences offer ways to understand this important dimension through investigating the attitudes and opinions of the key actors involved. The study reported in this paper, based on qualitative interview research, investigates the views of dairy farmers and cattle veterinarians on the drivers and incentives for controlling Johne's disease in English dairy herds. Twenty semi-structured interviews involving 17 dairy farmers and seven veterinarians were conducted in two dairy-intensive regions of England. The findings demonstrate the varied influences of veterinary advice and encouragement; appreciation of the economic cost of the disease at herd level; a voluntary national control plan; and fear of a future consumer food scare as the main reasons to engage in Johne's disease control on dairy farms. The study demonstrates how a combination of a voluntary industry-led control scheme, compulsory participation through retailer and processor contractual requirements, and threats of reputational harm and market loss have strongly influenced farmer and veterinary behaviour in relation to Johne's control without statutory involvement. The findings illustrate the importance of considering the political economy and societal impact of animal disease.

A description of biosecurity practices among selected dairy farmers across Australia

Aims The study investigated critical biosecurity control points and dairy farmers’ motivations towards biosecurity practices among selected dairy farmers across Australia. Methods A questionnaire template was administered via an online survey. A three-stage process was used to develop the questionnaire by pooling of potential questions, selection and reduction of the questions to fit an 8–10 min survey. Key results A total of 55 responses were obtained. Mixed species rearing was practiced on 69% of the farms, with a majority keeping either sheep or beef cattle within the same property as dairy cattle. Approximately half of the farms (49%) did not provide formal training to new staff on aspects of animal health, as well as not conducting bull breeding soundness. Most of the farms (98%) required staff to use personal protective equipment, such as overalls and gumboots, but only a few of the farms (34%) had designated areas to clean footwear and a system for recording visitors (17%). Record keeping pertaining to animal health, maintenance of good fences and use of vendor declaration forms was practiced in a majority of the farms. The practice of quarantining new stock before mixing with other stock was practiced in only 45% of the farms. Monthly herd health visits by a veterinarian were utilised by 55% of the farms. Multivariable analysis showed positive significant associations between mixed species rearing with the practice of regular pest control (P = 0.004) and use of footbaths (P = 0.024) and no biosecurity plan (P = 0.025). Furthermore, a positive significant association was also recorded on the presence of a biosecurity plan and the presence of a designated area to clean footwear (P = 0.002) and no regular deworming (P = 0.024). Animal and human health reasons were the main motivators for implementing and maintaining ‘best practice’ biosecurity practices, whereas government regulation was the lowest motivator. Conclusions It is concluded that the biosecurity practices were variable, and animal and human health reasons were the primary motivators for instituting biosecurity practices. Implications There is a need to continue educating farmers on the importance of biosecurity practices.

Controlling hepatitis E virus in the pig production sector: Assessment of the technical and behavioural feasibility of on-farm risk mitigation strategies

Hepatitis E virus (HEV) is a zoonotic agent with pigs as the main reservoir in industrialised countries. Recent studies conducted on pig farms, in experimental conditions or through modelling approaches, have led to a better understanding of the spread of HEV on pig farms. The findings have also made it possible to define a set of measures to reduce HEV prevalence and the risk of marketing contaminated products. The objective of this study was to assess the feasibility of a set of HEV control strategies on pig farms. Individual semi-structured interviews were conducted with farmers, veterinarians and farming advisors to collect general data, their level of knowledge of HEV, their opinion on the technical feasibility of certain changes in practices, their perception of the respective responsibilities of the different stakeholders, and their feelings about the importance of the issue, following the framework of the Theory of Planned Behaviour. The interviews made it possible to highlight potential barriers and preferred motivators for the implementation of on-farm risk mitigation strategies. Barriers included lack of knowledge, scientific gaps, perceived inability to control HEV, and low perception of the importance of the issue. Motivators included professional satisfaction, family recognition, and the opportunity to achieve higher quality standards. Three clusters of stakeholders were also identified, with a group of leaders who could help unlock reluctance and disseminate innovations. This type of behavioural approach appeared useful to help risk managers facilitate zoonotic control on pig farms.

Exploring dairy producer and veterinarian perceptions of barriers and motivators to adopting on-farm management practices for Johne's disease control in Ontario, Canada

Motivating uptake of management change recommendations requires knowledge of the barriers and motivators influencing producer behavior. This study investigated dairy producers' and veterinarians' perceptions of the barriers and motivators influencing the adoption of Johne's disease (JD) control recommendations in Ontario, Canada. Eight focus groups, 6 with dairy producers and 2 with veterinarians, were conducted and thematically analyzed. Both producer and veterinarian groups identified physical resources (i.e., time, money, infrastructure) and producer mindset (i.e., perceived priority of JD, perceived practicality of JD control recommendations) as key barriers to adoption. Producers tended to prioritize JD control on their farm based on their lived experiences with JD and their view of the public's concern about JD. Many agreed that JD recommendations should focus on biosecurity more holistically and emphasize the broader health benefits of limiting calf exposure to many fecal-orally transmitted diseases. Producers also highlighted that some recommendations for on-farm change (i.e., keeping a closed herd, buying from low-risk herds) were unrealistic or too difficult to perform and often disrupted their habits or routine. In contrast, veterinarians suggested that most recommendations were practical and are routinely recommended. Participants suggested both extrinsic (i.e., incentives, premiums, penalties and regulations, and extension and communication) and intrinsic (i.e., pride and responsibility) methods for motivating producers. This study highlights the importance of producer mindset in on-farm change and offers insights into the attitudes and perceived barriers influencing on-farm change.

Knowledge gaps that hamper prevention and control of Mycobacterium avium subspecies paratuberculosis infection

In the last decades, many regional and country-wide control programmes for Johne's disease (JD) were developed due to associated economic losses, or because of a possible association with Crohn's disease. These control programmes were often not successful, partly because management protocols were not followed, including the introduction of infected replacement cattle, because tests to identify infected animals were unreliable, and uptake by farmers was not high enough because of a perceived low return on investment. In the absence of a cure or effective commercial vaccines, control of JD is currently primarily based on herd management strategies to avoid infection of cattle and restrict within-farm and farm-to-farm transmission. Although JD control programmes have been implemented in most developed countries, lessons learned from JD prevention and control programmes are underreported. Also, JD control programmes are typically evaluated in a limited number of herds and the duration of the study is less than 5 year, making it difficult to adequately assess the efficacy of control programmes. In this manuscript, we identify the most important gaps in knowledge hampering JD prevention and control programmes, including vaccination and diagnostics. Secondly, we discuss directions that research should take to address those knowledge gaps.

Epidemiological and economic consequences of purchasing livestock infected with Mycobacterium avium subsp. paratuberculosis

Background

Paratuberculosis (PTB) is a chronic disease which may lead to reduced milk yield, lower animal welfare and death in cattle. The causative agent is Mycobacterium avium subsp. paratuberculosis (MAP). The economic consequences are particularly important incentives in the control and eradication of the infection.

One strategy to control PTB in a herd is to purchase animals from farms with a low risk of MAP infection. We wanted to investigate the epidemiological and economic consequences of buying livestock from different supplier farms of low, medium or high risk, as well as farms with unknown status. We also wanted to estimate the probability of spontaneous fadeout if the farmer of an initially MAP-free herd bought a specified number of infected animals in a single year, or continually bought infected animals. This was achieved through simulation modeling, and the effects of consistently introducing one, five or ten infected animals annually into an initially infection-free herd was also modeled.

Results

Our findings show that once infected, a farm can relatively safely purchase animals from other low and medium-risk farms without experiencing an increase in the prevalence, highlighting the importance of certification programmes. Furthermore, farms free of MAP are highly susceptible and cannot purchase more than a small number of animals per year without having a high risk of being infected. The probability of spontaneous fadeout after 10 years was 82% when introducing a single infected animal into an initially MAP-free herd. When purchasing ten infected animals, this probability was 46%. The continual purchase of infected animals resulted in very low probabilities of spontaneous fadeout.

Conclusions

We demonstrated that MAP-free farms can purchase a small number of animals, preferably from certified farms, each year and still remain free of MAP. Already infected farms have little risk of increasing the prevalence on a farm when purchasing animals from other farms.

Invited review: Determinants of farmers' adoption of management-based strategies for infectious disease prevention and control

The prevention and control of endemic pathogens within and between farms often depends on the adoption of best management practices. However, farmers regularly do not adopt recommended measures or do not enroll in voluntary disease control programs. This indicates that a more comprehensive understanding of the influences and extension tools that affect farmers' management decisions is necessary. Based on a review of relevant published literature, we developed recommendations to support policy-makers, industry representatives, researchers, veterinarians, and other stakeholders when motivating farmers to adopt best management practices, and to facilitate the development and implementation of voluntary prevention and control programs for livestock diseases. Farmers will make management decisions based on their unique circumstances, agricultural contexts, beliefs, and goals. Providing them with rational but universal arguments might not always be sufficient to motivate on-farm change. Implementation of recommended management practices is more likely if farmers acknowledge the existence of a problem and their responsibility to take action. The perceived feasibility and effectiveness of the recommended management strategy and sufficient technical knowledge further increase the likelihood of adequate adoption. Farmers will also weigh the expected advantages of a proposed change against the expected disadvantages, and these considerations often include internal drivers such as pride or the desire to conform with perceived standards. Extension tools and farmers' social referents (e.g., veterinarians, peers) not only provide technical information but also influence these standards. Whereas mass media have the potential to deliver information to a broad audience, more personal approaches such as participatory group learning or individual communication with farm advisors can enable the tailoring of recommendations to farmers' situations. Approaches that appeal to farmers' internal motivators or that unconsciously elicit the desired behavior will increase the success of the intervention. Collaboration among stakeholders, assisted by social scientists and communication specialists, is necessary to provide a context that facilitates on-farm change and transfers consistent messages across extension tools in the most effective way.

Dairy farmers' perceptions toward the implementation of on-farm Johne's disease prevention and control strategies

Implementation of specific management strategies on dairy farms is currently the most effective way to reduce the prevalence of Johne's disease (JD), an infectious chronic enteritis of ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP). However, dairy farmers often fail to implement recommended strategies. The objective of this study was to assess perceptions of farmers participating in a JD prevention and control program toward recommended practices, and explore factors that influence whether or not a farmer adopts risk-reducing measures for MAP transmission. Semi-structured interviews were conducted with 25 dairy farmers enrolled in a voluntary JD control program in Alberta, Canada. Principles of classical grounded theory were used for participant selection, interviewing, and data analysis. Additionally, demographic data and MAP infection status were collected and analyzed using quantitative questionnaires and the JD control program database. Farmers' perceptions were distinguished according to 2 main categories: first, their belief in the importance of JD, and second, their belief in recommended JD prevention and control strategies. Based on these categories, farmers were classified into 4 groups: proactivists, disillusionists, deniers, and unconcerned. The first 2 groups believed in the importance of JD, and proactivists and unconcerned believed in proposed JD prevention and control measures. Groups that regarded JD as important had better knowledge about best strategies to reduce MAP transmission and had more JD risk assessments conducted on their farm. Although not quantified, it also appeared that these groups had more JD prevention and control practices in place. However, often JD was not perceived as a problem in the herd and generally farmers did not regard JD control as a "hot topic" in communications with their herd veterinarian and other farmers. Recommendations regarding how to communicate with farmers and motivate various groups of farmers according to their specific perceptions were provided to optimize adoption of JD prevention and control measures and thereby increase success of voluntary JD control programs.

The Single Intradermal Cervical Comparative Test Interferes with Johne's Disease ELISA Diagnostics

Enzyme-linked immunosorbent assays (ELISA) of milk and serum samples are a routinely used method of screening herds for Mycobacterium avium subspecies paratuberculosis (MAP). Infection with MAP causes granulomatous enteritis of ruminants known as Johne's disease (JD). The sensitivity (Se) and specificity (Sp) of MAP ELISAs leads to difficulties in the identification of both infected and infectious animals. Interference with MAP ELISA Se and Sp has been reported in MAP seronegative cows following administration of purified protein derivative (PPD) as part of intradermal testing for bovine tuberculosis (bTB). The aim of this study is to examine the impact of the single intradermal cervical comparative test (SICCT) for bTB, on both serum and milk MAP ELISA tests, in a herd containing both seropositive and seronegative cows pre-SICCT. A secondary objective is to provide appropriate timing of JD ELISA tests in relation to the SICCT. A herd of 139 cows were serum and milk sampled pre- and post-SICCT administration. Prior to SICCT, 6% of the herd tested seropositive for MAP using milk ELISA, with 8% positive on serum. ID Screen Paratuberculosis Indirect Screening Test (ID Vet) was used to screen the herd. Within 14 days of PPD administration, a significant increase in the prevalence of seropositive cows was recorded. Identical prevalence's were recorded with both test matrices (39%). ELISA values remained significantly higher until day 43 post-SICCT in milk (P = 0.850), and day 71 in serum (P = 0.602). If the "new" positives detected post-bTB testing are deemed false positives due to generation of cross-reacting antibodies by administration of PPD, milk would appear a more suitable sample for JD ELISA testing within 2 months of SICCT. In summary, sampling for JD utilizing milk ELISA should be avoided in the 43-day period following PPD administration, with serum ELISA sampling avoided for an additional 28 days.