Modelling the economic efficiency of using different strategies to control Porcine Reproductive & Respiratory Syndrome at herd level

PRRS is among the diseases with the highest economic impact in pig production worldwide. Different strategies have been developed and applied to combat PRRS at farm level. The broad variety of available intervention strategies makes it difficult to decide on the most cost-efficient strategy for a given farm situation, as it depends on many farm-individual factors like disease severity, prices or farm structure. Aim of this study was to create a simulation tool to estimate the cost-efficiency of different control strategies at individual farm level. Baseline is a model that estimates the costs of PRRS, based on changes in health and productivity, in a specific farm setting (e.g. farm type, herd size, type of batch farrowing). The model evaluates different intervention scenarios: depopulation/repopulation (D/R), close & roll-over (C&R), mass vaccination of sows (MS), mass vaccination of sows and vaccination of piglets (MS + piglets), improvements in internal biosecurity (BSM), and combinations of vaccinations with BSM. Data on improvement in health and productivity parameters for each intervention were obtained through literature review and from expert opinions. The economic efficiency of the different strategies was assessed over 5 years through investment appraisals: the resulting expected value (EV) indicated the most cost-effective strategy. Calculations were performed for 5 example scenarios with varying farm type (farrow-to-finish – breeding herd), disease severity (slightly – moderately – severely affected) and PRRSV detection (yes – no). The assumed herd size was 1000 sows with farm and price structure as commonly found in Germany. In a moderately affected (moderate deviations in health and productivity parameters from what could be expected in an average negative herd), unstable farrow-to-finish herd, the most cost-efficient strategies according to their median EV were C&R (€1′126′807) and MS + piglets (€ 1′114′649). In a slightly affected farrow-to-finish herd, no virus detected, the highest median EV was for MS + piglets (€ 721′745) and MS (€ 664′111). Results indicate that the expected benefits of interventions and the most efficient strategy depend on the individual farm situation, e.g. disease severity. The model provides new insights regarding the cost-efficiency of various PRRSV intervention strategies at farm level. It is a valuable tool for farmers and veterinarians to estimate expected economic consequences of an intervention for a specific farm setting and thus enables a better informed decision

Severity of bovine tuberculosis is associated with co-infection with common pathogens in wild boar

Co-infections with parasites or viruses drive tuberculosis dynamics in humans, but little is known about their effects in other non-human hosts. This work aims to investigate the relationship between Mycobacterium bovis infection and other pathogens in wild boar (Sus scrofa), a recognized reservoir of bovine tuberculosis (bTB) in Mediterranean ecosystems. For this purpose, it has been assessed whether contacts with common concomitant pathogens are associated with the development of severe bTB lesions in 165 wild boar from mid-western Spain. The presence of bTB lesions affecting only one anatomic location (cervical lymph nodes), or more severe patterns affecting more than one location (mainly cervical lymph nodes and lungs), was assessed in infected animals. In addition, the existence of contacts with other pathogens such as porcine circovirus type 2 (PCV2), Aujeszky's disease virus (ADV), swine influenza virus, porcine reproductive and respiratory syndrome virus, Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, Haemophilus parasuis and Metastrongylus spp, was evaluated by means of serological, microbiological and parasitological techniques. The existence of contacts with a structured community of pathogens in wild boar infected by M. bovis was statistically investigated by null models. Association between this community of pathogens and bTB severity was examined using a Partial Least Squares regression approach. Results showed that adult wild boar infected by M. bovis had contacted with some specific, non-random pathogen combinations. Contact with PCV2, ADV and infection by Metastrongylus spp, was positively correlated to tuberculosis severity. Therefore, measures against these concomitant pathogens such as vaccination or deworming, might be useful in tuberculosis control programmes in the wild boar. However, given the unexpected consequences of altering any community of organisms, further research should evaluate the impact of such measures under controlled conditions. Furthermore, more research including other important pathogens, such as gastro-intestinal nematodes, will be necessary to complete this picture

Seroprevalence of Salmonella sp. on sixteen small one-site pig farms in Slovenia

Salmonellosis is considered to be one of the most common food-borne illnesses in humans. Swine can be infected with a broad range of salmonella serotypes that can be source of infection of pork products. Salmonella reduction programs on pig farms can be achieved with serological monitoring. It is important to identify pig farms that carry a high percentage of infected animals, hence represent a bigger risk factor for introducing salmonella in the meat production chain. Proper measures should be introduced to reduce the salmonella contamination on infected farms. Between years 2012 and 2014, 16 small one-site pig farms participated in a study of seroprevalence of different pathogens, including Salmonella sp. During the research, 166 sera samples were tested for presence of antibodies against salmonella with ELISA Swine Salmonella Antibody Test Kit (IDEXX). Samples with OD % equal or greater than 20 % (S/P = 0.5) were classified as positive (more stringent screening). 21 % of breeding animals and 5.8 % of fatteners were serologicaly positive. Compared to previous studies, it is apparent that seroprevalence of salmonella on pig farms in Slovenia has not augmented (2006 OD 20 % was 21.3 %, 2007 OD 20 % was 24 % and 2008 OD 20 % was 24.8 %). Seroprevalence is still low in Slovenia. Aside from the level of primary production, it is important to continue monitoring in other stages of the food chain, such as food and animal feed.</p

Biosecurity challenges in extensive domestic pig farming in two countries: Serbia and Slovenia

Biosecurity measures are considered the most important instrument for preventing the introduction of African swine fever (ASF) into pig production systems. Especially in extensive pig production, biosecurity measures must be practical to implement, and understandable for farmers. In 2023, the bilateral Serbia-Slovenia country project has started with the aim of mapping and evaluating biosecurity measures in different pig production systems and establishing a link between herd biosecurity and the potential risk of ASF introduction. On the one hand, the project will address this through a recent epidemiological study in ASF-infected pig units (small farms, backyards) in Serbia. On the other hand, Slovenia, as an ASF-free country, is currently in the highest preparedness phase in view of the cases detected in the neighbouring countries. In 2019, ASF was detected in Serbia in extensive pig production. The rearing of pigs in backyards is a traditional practise in villages, but under certain conditions this type of unit can also be operated commercially. In contrast, extensive backyard pig production exists in Slovenia, but with varying degrees of regulation. In addition to backyard pig farming, there is an outdoor pig production oriented to the well-recognised pig breeds with labelled meat products (Krskopoljska pig). In 2023, the research groups from two countries visited Serbia and Slovenia to record and evaluate the specific factors in the structure of the country's pig production system. In Serbia, the field visits were carried out in the regions affected by ASF. In Slovenia, the extensive pig production units with outdoor pig production were visited and the country's measures to combat ASF were presented. The global dimension of ASF, including long-distance translocations, shows that all countries are at risk: Human-mediated spread to domestic pigs can occur at any time and in any country, regardless of the distance to ongoing infections.Book of abstract