Prioritization of pig farm biosecurity for control of Salmonella and hepatitis E virus infections: results of a European expert opinion elicitation

BackgroundIn the literature, there is absent or weak evidence on the effectiveness of biosecurity measures to the control of Salmonella spp. and hepatitis E virus (HEV) on pig farms. Therefore, the present study aimed to collect, weigh, and compare opinions from experts on the relevance of several biosecurity measures. An online questionnaire was submitted to selected experts, from multiple European countries, knowledgeable on either HEV or Salmonella spp., in either indoor or outdoor pig farming systems (settings). The experts ranked the relevance of eight biosecurity categories with regards to effectiveness in reducing the two pathogens separately, by assigning a score from a total of 80, and within each biosecurity category they scored the relevance of specific biosecurity measures (scale 1-5). Agreement among experts was analysed across pathogens and across settings.ResultsAfter filtering for completeness and expertise, 46 responses were analysed, with 52% of the experts identified as researchers/scientists, whereas the remaining 48% consisted of non-researchers, veterinary practitioners and advisors, governmental staff, and consultant/industrial experts. The experts self-declared their level of knowledge but neither Multidimensional Scaling nor k-means cluster analyses produced evidence of an association between expertise and the biosecurity answers, and so all experts' responses were analysed together without weighting or adaptation. Overall, the top-ranked biosecurity categories were pig mixing; cleaning and disinfection; feed, water and bedding; and purchase of pigs or semen, while the lowest ranked categories were transport, equipment, animals (other than pigs and including wildlife) and humans. Cleaning and disinfection was ranked highest for both pathogens in the indoor setting, whereas pig mixing was highest for outdoor settings. Several (94/222, 42.3%) measures across all four settings were considered highly relevant. Measures with high disagreement between the respondents were uncommon (21/222, 9.6%), but more frequent for HEV compared to Salmonella spp.ConclusionsThe implementation of measures from multiple biosecurity categories was considered important to control Salmonella spp. and HEV on farms, and pig mixing activities, as well as cleaning and disinfection practices, were perceived as consistently more important than others. Similarities and differences in the prioritised biosecurity measures were identified between indoor and outdoor systems and pathogens. The study identified the need for further research especially for control of HEV and for biosecurity in outdoor farming

What is a biosecurity measure? A definition proposal for animal production and linked processing operations

While biosecurity, a central component of the One Health concept, is clearly defined, a harmonized definition of the term ´biosecurity measure´ (BSM) is missing. In turn, particularly at the farm and policy level, this leads to misunderstandings, low acceptance, poor implementation, and thus suboptimal biosecurity along the food animal production chain. Moreover, different views on BSMs affects making comparisons both at the policy level as well as in the scientific community. Therefore, as part of the One Health EJP BIOPIGEE project, a work group i) collected and discussed relevant inclusion and exclusion criteria for measures to be considered in the context of biosecurity and ii) conducted a systematic literature review for potentially existing definitions for the term BSM. This exercise confirmed the lack of a definition of BSM, underlining the importance of the topic. In the pool of articles considered relevant to defining the term BSM, specific research themes were identified. Based on these outcomes, we propose a definition of the term BSM: “A biosecurity measure (BSM) – is the implementation of a segregation, hygiene, or management procedure (excluding medically effective feed additives and preventive/curative treatment of animals) that specifically aims at reducing the probability of the introduction, establishment, survival, or spread of any potential pathogen to, within, or from a farm, operation or geographical area.” The definition provides a basis for policymakers to identify factual BSMs, highlights the point of implementation and supports to achieve the necessary quality standards of biosecurity in food animal production. It also enables clear, harmonized, cross-sectoral communication of best biosecurity practices to and from relevant stakeholders and thus contribute to improving biosecurity and thereby strengthen the One Health approach

Monitoring der Eutergesundheit in Milchkuhherden

As herd sizes increase, the continuous monitoring becomes more important for dairy farmers and their veterinarians or consultants to maintain udder health. To avoid unnecessary expenditures for monitoring measures, recommendations are needed how to set up a monitoring system for a farm and which could be helpful indicators. Tools that simplify data analysis for monitoring purposes have to be developed. The overall objective of this thesis was to develop science- based recommendations for different aspects of the monitoring of the udder health on dairy farms on the product and the process level. On the product level, a tool to assess milk yield loss due to clinical mastitis in individual dairy herds was developed and prepared for implementation in a server-based software for monitoring dairy herds. On the process level, variables to monitor the teat condition and distinct negative energy balance as possible risk factors for mastitis were investigated. The procedure to establish a risk-based monitoring program for the udder health was summarized in a literature review. It consists of 1) setting goals, 2) a risk analysis, 3) planning of measures and the monitoring, 4) the implementation, and 5) the documentation and regular evaluation. A longitudinal field study was conducted to assess the influence of short-term and long-term alterations of the teat tissue and of the infectious status of the udder quarter on its risk of naturally occurring new intramammary infections, inflammatory responses, and mastitis. Changes of the teat condition of right udder quarters of 135 cows on a commercial dairy farm in Saxony-Anhalt, Germany, were recorded monthly for 10 months using simple classification schemes. Quarter milk samples were collected from all examined quarters at each farm visit. Bacteriological culture results and SCC of the quarter milk samples were used to determine new inflammatory responses (increase from ≤100,000 cells/mL to >100,000 cells/mL between two samples), new infections (detection of a pathogen from a quarter that was free of this pathogen at the preceding sampling), and new mastitis (combination of a new inflammatory response and a new infection). Separate mixed Poisson regression models for new inflammatory responses, new infections, and new mastitis caused by specific pathogens or groups of pathogens (contagious, environmental, major, minor, or any) were used to estimate risk ratios and 95% confidence intervals. There was no effect of any variable describing the teat condition on the risk of new intramammary infections, inflammatory responses, or mastitis. Intramammary infections of the same udder quarter in the preceding month did not have an influence either. In a retrospective cohort study, the association between the test day milk fat-protein ratio and the incidence rate of clinical mastitis was investigated in consideration of repeated cases of clinical mastitis. The objective of this study was to assess the validity of the test day milk fat- protein ratio as a monitoring variable for metabolic disorders as risk factors for the udder health. Herd records of 10 dairy herds of Holstein cows in Saxony, Germany, from September 2005 to September 2011 that compromised of 36,827 lactation periods of 17,657 cows were used for statistical analysis. A mixed Poisson regression model with the weekly incidence rate of clinical mastitis as the outcome variable was fitted that included repeated events of the outcome, updated measurements of independent variables, and multilevel clustering. Previous cases of clinical mastitis increased the incidence rate of clinical mastitis. However, given the assumptions that were made about the bias parameters and the methods used for the bias analysis, these conventional results were biased toward the null by the misclassification of clinical mastitis. Fat-protein ratios of 1.5 were associated with higher incidence rates of clinical mastitis depending on the week in milk. The effect of a fat-protein ratio >1.5 on the mastitis incidence rate increased considerably over the course of lactation whereas the effect of a fat-protein ratio 1.5 on the most recent test days of all cows irrespective of their time in milk seemed to be better predictors for clinical mastitis than the first test day results per lactation. A linear mixed model was developed to estimate the reduced milk yield and the milk loss due to clinical mastitis for a specific herd based on individual cows’ mastitis and daily milk yield data. The short and long term decrease in the daily milk yield was described by expanding the lactation curve model of Ali and Schaeffer (1987). For calculating the short term drop, the model included the laps of time in days since the mastitis incident as a second-degree polynomial. The coefficients were estimated specifically for the first respectively the recurrent cases of mastitis per lactation. The long term decrease was also modeled separately for the first and the recurrent cases by estimating lactation curves without mastitis as well as for the first and the recurrent cases. The milk yield could be estimated for each day in milk according to the episode number and the time elapsed since the incident or with no mastitis incident, respectively, for a particular period of time in a specific dairy herd. The loss resulting from the reduced performance due to clinical mastitis would be specified by adding up the differences. None of the variables that were evaluated in this thesis could be recommended to monitor possible risk factors for mastitis. Monitoring the teat condition to control the udder health seemed to be wasteful in most cases as the teat condition did not influence the risk of mastitis. The ability of test day milk fat-protein ratios 1.5 to predict clinical mastitis was very small and other measures to monitor metabolic disorders as risk factors for mastitis should be evaluated. However, a useful tool was developed to provide dairy farmers with herd-specific information about milk loss due to clinical mastitis as basis for management decisions.Mit steigenden Herdengrößen wird die kontinuierliche Überwachung für Milchkuhhalter und ihre Tierärzte oder Berater immer wichtiger, um die Eutergesundheit der Herden zu erhalten. Um unnötige Ausgaben für Überwachungsmaßnahmen zu vermeiden, werden Empfehlungen benötigt, wie ein herdenspezifisches Monitoringsystem eingerichtet werden kann und welches nützliche Indikatoren sind. Werkzeuge, die die Datenanalyse für das Monitoring vereinfachen, müssen entwickelt werden. Das Ziel dieser Dissertation war es, wissenschaftlich fundierte Empfehlungen für verschiedene Aspekte des Euter­gesundheits­monitorings auf Produkt- und Prozessebene in Milchkuhherden zu entwickeln. Auf Produktebene wurde ein Werkzeug zur Bestimmung des Milchverlusts durch klinische Mastitis in einzelnen Milchkuhherden entwickelt und für die Einbindung in ein serverbasiertes Computerprogramm zum Monitoring von Milchkuhherden vorbereitet. Auf Prozessebene wurden Variablen zum Monitoring der Zitzenkondition und deutlich negativer Energiebilanz als möglichen Risikofaktoren für Mastitiden untersucht. Wie man vorgeht, um ein risikobasiertes Monitoringprogramm für die Euter­gesund­heit einzurichten, wurde in einer Literaturübersicht beschrieben. Ein risikobasiertes Monitoringprogramm besteht aus 1) der Zielsetzung, 2) der Risikoanalyse, 3) der Planung von Maßnahmen und des Monitorings, 4) der Umsetzung und 5) der Dokumentation und regelmäßigen Evaluation. Eine longitudinale Feldstudie wurde durchgeführt, um den Einfluss von kurz- und langfristigen Veränderungen des Zitzengewebes und des Infektionsstatus des Euterviertels auf das Risiko von natürlich auftretenden neuen intramammären Infektionen, Entzündungsreaktionen und Mastitiden zu bestimmen. Veränderungen der Zitzenkondition an den rechten Eutervierteln von 135 Kühen eines kommerziellen Milchkuhbetriebs in Sachsen- Anhalt wurden monatlich über zehn Monate mit Hilfe eines einfachen Schemas dokumentiert. Bei jedem Besuch wurden von allen untersuchten Vierteln Viertelgemelksproben entnommen. Die Ergebnisse der zytobakteriologischen Untersuchungen der Viertelgemelksproben wurden verwendet, um neue entzündliche Reaktionen (Anstieg von ≤100.000 Zellen/ml auf >100.000 Zellen/ml zwischen zwei Untersuchungen), Neuinfektionen (Nachweis eines Mastitiserregers in einem Viertel, der bei der vorangegangenen Untersuchung aus diesem Viertel nicht isoliert wurde) und neue Mastitiden (Kombination von neuer Entzündungsreaktion und Neuinfektion) zu bestimmen. Mittels getrennter gemischter Poissonregressionen wurden relative Risken mit 95% Konfidenzintervallen für neue Entzündungsreaktionen, Neuinfektionen und neue Mastitiden mit bestimmten Keimen oder Keimgruppen (kuhassoziiert, umweltassoziiert, major, minor oder irgendein) geschätzt. Keine Variable zur Beschreibung der Zitzenkondition hatte Einfluss auf das Risiko von Neuinfektionen, neuer entzündlicher Reaktionen oder neuer Mastitiden. Auch intramammäre Infektionen des selben Euterviertels im vorangegangenen Monat beeinflussten das Risiko nicht. Die Beziehungen zwischen dem Fett-Eiweiß-Quotienten am Tag der Milchleistungsprüfung und der Inzidenz klinischer Mastitis unter Berücksichtigung wiederholter Fälle wurden in einer retrospektiven Kohorten­studie untersucht. Das Ziel der Untersuchung war es, zu bestimmen, ob sich der Milchfett-Eiweiß-Quotient aus der Milchleistungsprüfung dafür eignet, auf Stoffwechselstörungen als Risikofaktoren für Euterentzündungen hinzuweisen. Aufzeichnungen von zehn Milchkuhherden aus Holsteinkühen in Sachsen von September 2005 bis September 2011, die 36.827 Laktationen von 17.657 Kühen umfassten, wurden statistisch untersucht. Dazu wurde ein gemischtes Poissonregressionsmodell mit der wöchentlichen Inzidenzrate klinischer Mastitiden als abhängiger Variablen erstellt, das wiederholte Ereignisse der abhängigen Variablen, erneute Messungen unabhängiger Variablen und Gruppierungen auf mehreren Ebenen enthielt. Vorangegangene klinische Mastitiden erhöhten die Inzidenzrate klinischer Mastitis. Allerdings erwiesen sich diese Ergebnisse unter den getroffenen Annahmen über die Biasparameter und mit den verwendeten Methoden in der Biasanalyse als zur Null hin verzerrt. Fett-Eiweiß-Quotienten 1,5 standen in Zusammenhang mit einer höheren Mastitis­inzidenz­rate in Abhängigkeit von der Laktations­woche. Der Einfluss eines Fett-Eiweiß-Quotienten >1,5 auf die Mastitis­inzidenz­rate stieg im Laktationsverlauf deutlich an, während der Einfluss eines Fett-Eiweiß- Quotienten 1,5 in der aktuellsten Milchleistungs­prüfung unabhängig vom Laktations­status schienen klinische Mastitiden besser vorhersagen zu können als die Ergebnisse aus der ersten Milch­leistungs­prüfungen pro Laktation. Zur Schätzung der reduzierten Milchleistung und des Milch­verlusts durch klinische Mastitis in einer bestimmten Herde wurde ein lineares gemischtes Modell erstellt auf Grundlage der Mastitisdaten und täglichen Milchleistung der einzelnen Kühe. Die kurz- und langfristige Reduktion der täglichen Milchmenge wurde durch Erweiterungen des Laktations­kurven­modells von Ali und Schaeffer (1987) beschrieben. Um den kurzfristigen Leistungseinbruch darzustellen, enthielt das Modell die Zeitabstände zum Mastitisfall in Tagen als Polynom zweiten Grades. Die Koeffizienten wurden separat für den ersten beziehungsweise die Wiederholungsfälle pro Laktation geschätzt. Die langfristige Leistungsminderung wurde ebenfalls separat für erste und Wiederholungsfälle abgebildet, indem sowohl Laktationskurven ohne Mastitis als auch mit einer beziehungsweise mehreren Mastitiden geschätzt wurden. Für jeden Laktationstag in einer Herde in einem bestimmten Zeitraum könnte dann die Milchmenge entsprechend der Mastitis­fall­nummer und der Zeit seit dem Fall beziehungsweise ohne Mastitis geschätzt werden. Der Verlust durch die reduzierte Milchleistung in Folge klinischer Mastitis ergäbe sich dann als Summe der Differenzen. Keine der Variablen, die im Rahmen dieser Dissertation untersucht wurden, konnte zum Monitoring möglicher Risikofaktoren für Mastitis empfohlen werden. Die Überwachung der Zitzen­kondition, um die Euter­gesundheit zu kontrollieren, schien in den meisten Fällen nutzlos, weil die Zitzen­kondition das Risiko für Mastitis nicht beeinflusste. Die Möglichkeiten, mit dem Milchfett-Eiweiß-Quotient aus der Milchleistungs­prüfung das Auftreten klinischer Mastitis vorherzusagen, sind sehr gering. Andere Maßnahmen zur Überwachung von Stoffwechsel­störungen als Risikofaktoren für Mastitis sollten untersucht werden. Es wurde aber ein nützliches Werkzeug entwickelt, das Milchkuhhaltern herden­spezifische Information über den Milchverlust durch klinische Mastitis als Grundlage für Management­entscheidungen bereitstellen kann

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

What is a biosecurity measure? A definition proposal for animal production and linked processing operations

While biosecurity, a central component of the One Health concept, is clearly defined, a harmonized definition of the term ´biosecurity measure´ (BSM) is missing. In turn, particularly at the farm and policy level, this leads to misunderstandings, low acceptance, poor implementation, and thus suboptimal biosecurity along the food animal production chain. Moreover, different views on BSMs affects making comparisons both at the policy level as well as in the scientific community. Therefore, as part of the One Health EJP BIOPIGEE project, a work group i) collected and discussed relevant inclusion and exclusion criteria for measures to be considered in the context of biosecurity and ii) conducted a systematic literature review for potentially existing definitions for the term BSM. This exercise confirmed the lack of a definition of BSM, underlining the importance of the topic. In the pool of articles considered relevant to defining the term BSM, specific research themes were identified. Based on these outcomes, we propose a definition of the term BSM: “A biosecurity measure (BSM) – is the implementation of a segregation, hygiene, or management procedure (excluding medically effective feed additives and preventive/curative treatment of animals) that specifically aims at reducing the probability of the introduction, establishment, survival, or spread of any potential pathogen to, within, or from a farm, operation or geographical area.” The definition provides a basis for policymakers to identify factual BSMs, highlights the point of implementation and supports to achieve the necessary quality standards of biosecurity in food animal production. It also enables clear, harmonized, cross-sectoral communication of best biosecurity practices to and from relevant stakeholders and thus contribute to improving biosecurity and thereby strengthen the One Health approach