Carry-over risks in fattening units for Campylobacter spp.

There is a lack of information about the prevalence of the important zoonotic pathogens Campylobacter spp. and Yersinia spp. at different stages in the pig production chain. The aim of this study was to determine these prevalence in a total of 1 040 faecal samples and to gather further information about the sources of infection with Campylobacter spp. and their qualitative and quantitative importance in the pig production. During the slaughtering process, 122 pigs and their carcasses respectively, were sampled three times. Campylobacler spp. were isolated in sows (33.8%), piglets (80.9%), growing (89.2%) and finishing (64.7%) pigs. Yersinia spp. were detected in growing (15.2%) and finishing (13.3%) pigs only. For statistical analysis, bacteriological results for Campylobacter spp. were evaluated with questionnaire facts from four farrowing and twelve fattening units. In the production stage farrowing, a significant influence for the factors number of sows and forage store cleaning was detected by a generalized linear model. In the production stage fattening, following factors had a significant effect on the Campylobacler spp. prevalence: number of fattening places , mixed farm , sampling time , bottom , forage , antibacterial and anthelmintic prophylaxis

Association between antimicrobial usage, biosecurity measures as well as farm performance in German farrow-to-finish farms

Background: Antimicrobial usage in food producing animals is of major concern. A clear link between the extent of use and the development of antimicrobial resistance has already been demonstrated. To evaluate strategies that may reduce the antimicrobial usage while assuring pig health and welfare, it requires profound knowledge of factors that are associated with antimicrobial usage. Data on biosecurity and herd management practices are important parameters to identify risk factors which are related to a higher antimicrobial usage. To investigate between-farm variations of high and low usage the treatment incidence (TI) per age group in 60 German farrow-to-finish herds was qualitatively and quantitatively analysed and linked to biosecurity measures, and herd management characteristics. Results: Weaned pigs received most of the treatments (median TI=487.6), followed by suckling pigs (median TI=138.9). Suckling pigs were treated with critically important antimicrobials (3rd and 4th generation cephalosporines) to a remarkable extent. The number of sows present at site (p<0.01) and a low score for external biosecurity (p=0.06) were associated with a higher antimicrobial usage in pigs from birth till slaughter. Herds with a higher treatment incidence in growing pigs (TI 200days): i) were located in a region with a high pig density (p<0.01), ii) had a less strict access check for visitors and personnel (p<0.01) and iii) scored lower in the subcategory cleaning and disinfection' (internal biosecurity) (p<0.01). Herds with a higher treatment incidence in breeding pigs weaned more piglets per sow and year and scored better in the internal biosecurity level (p=0.02). Conclusions: With the main focus on the treatment incidence in pigs from birth till slaughter and in breeding pigs risk factors for a high usage in these age groups were identified. The level of biosecurity of a herd was associated with the amount of antimicrobials used. Therefore, the findings in this study indicate possible points of action in the reduction and prudent use of antimicrobials in Germany. The active improvement of biosecurity measures could be a promising alternative to reduce antimicrobial usage on herd level

Herd specific risk factors for Mycoplasma hyopneumoniae infections in suckling pigs at the age of weaning

BACKGROUND Mycoplasma hyopneumoniae is the etiologic agent of enzootic pneumonia mainly occurring in fattening pigs. It is assumed that horizontal transmission of the pathogen during nursery and growing phase starts with few suckling pigs vertically infected by the sow. The aim of the present study was the exploration of the herd prevalence of M. hyopneumoniae infections in suckling pigs followed by an investigation of various herd specific factors for their potential of influencing the occurrence of this pathogen at the age of weaning. RESULTS In this cross-sectional study, 125 breeding herds were examined by taking nasal swabs from 20 suckling pigs in each herd. In total, 3.9% (98/2500) of all nasal swabs were tested positive for M. hyopneumoniae by real-time PCR. Piglets tested positive originated from 46 different herds resulting in an overall herd prevalence of 36.8% (46/125) for M. hyopneumoniae infection in pigs at the age of weaning. While the herds were epidemiologically characterized, the risk for demonstration of M. hyopneumoniae was significantly increased, when the number of purchased gilts per year was more than 120 (OR: 5.8), and when the number of farrowing pens per compartment was higher than 16 (OR: 3.3). In herds with a planned and segregated production, where groups of sows entered previously emptied farrowing units, the risk for demonstration of M. hyopneumoniae in piglets was higher in herds with two or four weeks between batches than in herds with one or three weeks between batches (OR: 2.7). CONCLUSIONS In this cross-sectional study, several risk factors could be identified enhancing the probability of breeding herds to raise suckling pigs already infected with M. hyopneumoniae at the time of weaning. Interestingly, some factors (farrowing rhythm, gilt acclimatisation issues) were overlapping with those also influencing the seroprevalences among sows or the transmission of the pathogen between older age groups. Taking the multifactorial character of enzootic pneumonia into account, the results of this study substantiate that a comprehensive herd specific prevention programme is a prerequisite to reduce transmission of and disease caused by M. hyopneumoniae

A longitudinal study into the interaction between PRRSV and Mycoplasma hyopneumoniae in finishing pigs

A synergistic interaction between the Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) and other porcine respiratory infectious agents for the Porcine Respiratory Disease Complex (PRDC) in growing and finishing pigs has been suggested mostly based on empirical observations in the field. So far, most scientific investigations have been conducted under experimental conditions, as infection with several viral or bacterial agents during the acute stage of PRRSV infection, i.e. the interval between the PRRS and the second infectious agent, has always been relatively short. Little is known, however, about the real time span between the infections in case of dual infections with PRRSV and Mycoplasma hyopneumoniae under field conditions. The presented investigation was a longitudinal study over two years in a fattening herd with an all-in/all-out system. Altogether 3574 pigs (8 fattening groups) with 4-11 different origins per group were clinically investigated every second day during the whole fattening period. Ten percent of the pigs from each fattening group were individually marked and bled at 7 points of time. The sera were tested for antibodies against PRRSV by means of an IPMA (carried out at the Federal Research Centre for Virus Diseases of Animals, Tübingen, Germany) and for antibodies against M. hyopneumoniae by means of an ELISA (carried out with the ELISA test kit by Bommeli AG, Bern, Switzerland). Growth performance was calculated for all serologically investigated pigs, and slaughter checks were done as well. Taking published results into account, a time interval of 14 days after the last possible point of infection with the PRRSV was defined for estimating the frequency of infections with M. hyopneumoniae during the acute stage of PRRSV infection. For determining the time of infection with the PRRSV, a time interval of 7 days, and for M. hyopneumoniae a time interval of 21 days between infection and seroconversion was assumed. At the beginning of the grow-finish period, when the pigs were on average 75 days old, 19% had antibodies against PRRSV and only 0.6% antibodies against M. hyopneumoniae. After two weeks, 53% and after four weeks 95% of the pigs had antibodies against PRRSV. By the sixth week, all pigs, which had been PRRSV antibody negative at the time of arrival on the farm, seroconverted. During the first weeks of the grow-finish period, only very few pigs seroconverted against M. hyopneumoniae, and no remarkable increase of seroconversion against M. hyopneumoniae took place before the time between the sixth and ninth week. Altogether 48% of the pigs had antibodies against M. hyopneumoniae at the end of the fattening period. The seroconversion against M. hyopneumoniae correlated significantly with the prevalence of coughing. Altogether only 11% of the pigs had a seroconversion against M. hyopneumoniae and PRRSV within a short period of time. Further seroconversions against M. hyopneumoniae took place in a distance of several weeks when no or low risk for interactions is suggested. In total, pigs that seroconverted against M. hyopneumonia showed a significant growth retardation and pneumonic lesions were significantly increased, but there was no influence of the infection with M. hyopneumonia during the acute stage of PRRSV. Under the field conditions described, it appears that fattening pigs have only a low risk for infection with M. hyopneumoniae during the acute stage of PRRSV infection, since the seroconversion against M. hyopneumoniae took place only several weeks after the PRRS infection. This time interval is considerably longer than the time interval between infection and seroconversion in M. hyopneumoniae determined by most authors, which means that the majority of the infections with M. hyopneumoniae clearly took place long after the acute phase of PRRS. Based on the obtained results, there is no evidence for a significant involvement of PRRSV in the porcine respiratory disease complex (PRDC), as supposed by some researchers. No difference in the average daily weight gain and the frequency of pneumonic lesions at slaughter has been observed between pigs seroconverted against both agents within a short period of time, compared to pigs seroconverted within a period of several weeks/month

Review of the assessment of animal welfare with special emphasis on the "Welfare Quality^® animal welfare assessment protocol for growing pigs"

This paper discusses the arising need for an objective, but feasible, reliable and valid method for assessing animal welfare on farms. Animal welfare has become especially important since the industrialisation of animal housing after the Second World War and as public awareness and concern has increased. Simultaneously, alienation of the public from agriculture has taken place, as the population has moved increasingly from rural areas to towns. This has led to a very emotional discussion concerning the welfare of farmed animals, and thus a need for not only a clear definition but also a way of objectively measuring it has arisen. It is probably best defined as a total of the different conceptions health, natural behaviour and positive affective state. In the last few years, different methods for an objective assessment have been developed; however, all of them still face great challenges in their practical implementation and acceptance. The most promising method is probably the Welfare Quality^® (WQ) approach, especially as it concentrates on animal-based parameters. The development of the WQ protocols emphasised not only the different conceptions of animal welfare but also especially the feasibility, reliability and validity of the parameters to be included. One of the main challenges of these protocols remains, however, the final aggregation of the results to a welfare score. Furthermore, a thorough cost–benefit analysis has not been carried out so far. Even more importantly, only a few studies have addressed the general reliability and validity of the complete protocols, and those studies that have addressed these issues have also revealed challenges concerning the interobserver and test–retest reliability of some of the included parameters. As an example, this is discussed in detail for the "Welfare Quality^® animal welfare assessment protocol for growing pigs". In conclusion, the WQ approach can be seen as promising, but it has also revealed that there are still a considerable number of challenges that need to be addressed in further studies on the WQ protocols in order to achieve constant improvement. These challenges should be borne in mind in the application of these protocols, which should not be simply referred to as a gold standard

Carry-over risks in fattening units for Campylobacter spp.

There is a lack of information about the prevalence of the important zoonotic pathogens Campylobacter spp. and Yersinia spp. at different stages in the pig production chain. The aim of this study was to determine these prevalence in a total of 1 040 faecal samples and to gather further information about the sources of infection with Campylobacter spp. and their qualitative and quantitative importance in the pig production. During the slaughtering process, 122 pigs and their carcasses respectively, were sampled three times. Campylobacler spp. were isolated in sows (33.8%), piglets (80.9%), growing (89.2%) and finishing (64.7%) pigs. Yersinia spp. were detected in growing (15.2%) and finishing (13.3%) pigs only. For statistical analysis, bacteriological results for Campylobacter spp. were evaluated with questionnaire facts from four farrowing and twelve fattening units. In the production stage farrowing, a significant influence for the factors number of sows" and "forage store cleaning" was detected by a generalized linear model. In the production stage fattening, following factors had a significant effect on the Campylobacler spp. prevalence: "number of fattening places", "mixed farm", "sampling time", "bottom", "forage", "antibacterial" and "anthelmintic prophylaxis".</p

Evaluating perspectives for PRRS virus elimination from pig dense areas with a risk factor based herd index

Porcine reproductive and respiratory syndrome virus (PRRSV) is wide-spread in pig populations globally. In many regions of Europe with intensive pig production and high herd densities, the virus is endemic and can cause disease and production losses. This fuels discussion about the feasibility and sustainability of virus elimination from larger geographic regions. The implementation of a program aiming at virus elimination for areas with high pig density is unprecedented and its potential success is unknown. The objective of this work was to approach pig population data with a simple method that could support assessing the feasibility of a sustainable regional PRRSV elimination. Based on known risk factors such as pig herd structure and neighborhood conditions, an index characterizing individual herds' potential for endemic virus circulation and reinfection was designed. This index was subsequently used to compare data of all pig herds in two regions with different pig- and herd-densities in Lower Saxony (North-West Germany) where PRRSV is endemic. Distribution of the indexed herds was displayed using GIS. Clusters of high herd index densities forming potential risk hot spots were identified which could represent key target areas for surveillance and biosecurity measures under a control program aimed at virus elimination. In an additional step, for the study region with the higher pig density (2463 pigs/km(2) farmland), the potential distribution of PRRSV-free and non-free herds during the implementation of a national control program aiming at national virus elimination was modeled. Complex herd and trade network structures suggest that PRRSV elimination in regions with intensive pig farming like that of middle Europe would have to involve legal regulation and be accompanied by important trade and animal movement restrictions. The proposed methodology of risk index mapping could be adapted to areas varying in size, herd structure and density. Interpreted in the regional context, this could help to classify the density of risk and to accordingly target resources and measures for elimination