Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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A bead-based suspension array for the detection of Salmonella antibodies in pig sera
Wal, F.J. van der; Achterberg, R.P. ; Maassen, Catharina B.M. - \ 2018
Salmonella - serology - pig - swine - bead-based suspension array - LPS - triazine chemistry
Background Slaughter pigs are monitored for the presence of the zoonotic pathogen Salmonella, using both serology and bacteriology. ELISAs used to investigate pig herds are based on the detection of antibodies against components of the Salmonella cell envelope. Nearly all Salmonella isolates in food-producing animals are serovars of Salmonella enterica subspecies enterica, distributed over various serogroups as determined by the composition of their lipopolysaccharide (LPS). ELISAs for Salmonella serology are usually based on serogroup B and C1 LPS, often combined with serogroup D or E LPS. Although C2 LPS may improve serology, use of C2 LPS in a broad ELISA was never achieved. Results To enable detection of serum antibodies against Salmonella in pigs, a bead-based suspension array was developed with five LPS variants (B, 2Ă— C1, C2, D1), each conjugated to a different bead set using triazine chemistry. Reactivity of the beads was confirmed with rabbit agglutination sera and with experimental pig sera. With a mixture of bead sets, 175 sera from slaughter pigs were investigated for the presence of antibodies against Salmonella. With a combination of ROC analysis (B and D LPS) and a prevalence estimation based on historic data (C LPS), individual cut-offs were defined for each LPS-conjugated bead set, and assay performance was evaluated. Results of the suspension array (BC1C1C2D) suggest that more pigs are seroconverted than indicated by a commercial BC1D1-ELISA, and that most of these extra seropositive samples give a signal on one of the beads with C LPS. These results show that expansion of a standard panel with more C LPS variants improves antibody detection. Conclusions A suspension array for Salmonella serology in pigs was developed, that detects more seropositive sera than ELISA, which is achieved by expanding the panel of Salmonella LPS variants, including C2 LPS. The results demonstrate that bead-based suspension arrays allow for testing of pig sera, with the advantage of being able to set cut-offs per antigen. Ultimately, this type of assay can be applied in routine veterinary serology to test for antibodies against multiple Salmonella serovars (or other pathogens) in one single serum sample, using up-to-date antigen panels.
Carryover of cadmium from feed in growing pigs
Hoogenboom, L.A.P. ; Hattink, J. ; Polanen, A. van; Oostrom, J.J. van; Verbunt, J.T. ; Traag, W.A. ; Kan, K.A. ; Eijkeren, J.C.H. ; Boeck, G. de; Zeilmaker, M.J. - \ 2015
Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 32 (2015)1. - ISSN 1944-0049 - p. 68 - 79.
cd-saturation method - sludge-amended soil - metallothionein - tissues - growth - swine - accumulation - dioxins - protein - cortex
Growing male pigs were exposed to cadmium (Cd) at levels around 1 and 10 mg kg–1 feed for up to 12 weeks, administered as CdCl2 or Cd-cysteine (CdCys). Pigs exposed to 10 mg kg–1 showed decreased growth during the last 3 weeks. Liver and kidney concentrations of Cd continuously increased over the entire 12-week exposure, exceeding the European Union limits of 1.0 mg kg–1 (kidney) and 0.5 mg kg–1 (liver) within 3 weeks at the feed level of 10 mg kg–1. A switch to clean feed after 3 weeks for 5 or 9 weeks resulted in steadily decreased levels in kidney and liver, which could be completely attributed to organ growth. At the lower feed level, the level in kidney exceeded the limit almost twofold after 12 weeks, but not after 3 weeks. Liver levels remained below the limit. Metallothionein (MT) levels in livers showed a steady decrease in both untreated and treated animals over time. In kidney such a decrease was only observed in control animals, whereas in the highest-dosed animals the MT concentrations steadily increased. The observed carryover of Cd from feed to liver and kidney was modelled by means of a simple transfer model relating levels in feed via MT levels to accumulation of Cd. Using this model, it was shown that the exposure period of growing pigs to feed containing the European Union limit of 0.5 mg kg–1 feed should be less than 12 weeks in order to prevent Cd levels in the kidneys to exceed the European Union limit.
Lung pathogenicity of European genotype 3 strain porcine reproductive and respiratory syndrome virus (PRRSV) differs from that of subtype 1 strains.
Weesendorp, E. ; Rebel, J.M.J. ; Popma-de Graaf, D.J. ; Fijten, H.P.D. ; Stockhofe, N. - \ 2014
Veterinary Microbiology 174 (2014)1-2. - ISSN 0378-1135 - p. 127 - 138.
experimentally infected-pigs - lelystad virus - immunological responses - immune-responses - swine - cells - disease - expression - cytokines - virulence
Porcine reproductive and respiratory syndrome (PRRS) is difficult to control due to a high mutation rate of the PRRS virus (PRRSV) and the emergence of virulent strains. The objective of this study was to analyse early and late pathological responses in the respiratory tract after infection with the European PRRSV subtype 3 strain Lena in comparison to two European PRRSV subtype 1 strains: Belgium A and Lelystad-Ter Huurne (LV). For each virus strain, groups of twelve pigs were inoculated, and four pigs per group were euthanized at days 3, 7 and 35 post-infection (p.i.) for consecutive examination. Infection with strain Lena resulted in a more severe disease than with the subtype 1 strains, an inflammatory response within the first week of infection with expression of IL-1a in the lung and lymph node, and an influx of neutrophils and monocytes in bronchoalveolar lavage fluid (BALF). Infection with strain Belgium A or LV resulted in mild or no pathology within the first week of infection, but inflammatory cell influx in the lung interstititium was increased at the end of the experiment at day 35 p.i. At five weeks p.i., all strains induced a higher percentage of cytotoxic T cells and higher levels of IFN-¿ producing cells in BALF. This might have contributed to clearance of virus. In general, subtype 3 strain Lena induced a stronger early inflammatory response which led to more severe clinical disease and pathology. On the other hand, this may have supported an enhanced or faster clearance of virus in tissues, compared to subtype 1 strains.
Food and environmental routes of Hepatitis E virus transmission
Poel, W.H.M. van der - \ 2014
Current Opinion in Virology 4 (2014). - ISSN 1879-6257 - p. 91 - 96.
non-b-hepatitis - genetic-variability - family hepeviridae - liver sausage - pig-liver - wild boar - non-a - infection - replication - swine
Abstract Hepatitis E virus (HEV), genus Hepevirus, family hepeviridae is a main cause of epidemic hepatitis in developing countries and single cases of hepatitis in higher income countries. There are at least four HEV genotypes which have different epidemiologic and clinical features. Hepatitis E viruses are often transmitted via food and environmental routes. The actual role of these transmission routes in the spread of HEV can depend on the virus genotype, the environmental conditions, the hygienic conditions and the types of foods consumed. In this review food and environmental routes of HEV transmission are discussed to raise the awareness regarding the focal points for the development of accurate prevention and control strategies of HEV infection, food safety and public health protection.
Estimation of hepatitis E virus (HEV) pig seroprevalence using Elisa and Western blot and comparison between human and pig HEV sequences in Belgium.
Thiry, D. ; Mauroy, A. ; Saegerman, C. ; Thomas, I. ; Wautier, M. ; Miry, C. ; Czaplicki, G. ; Berkvens, D. ; Praet, N. ; Poel, W.H.M. van der; Cariolet, R. ; Brochier, B. ; Thiry, E. - \ 2014
Veterinary Microbiology 172 (2014)3-4. - ISSN 0378-1135 - p. 407 - 414.
antibodies - swine - transmission - infection - netherlands - populations - prevalence - france - meat - farm
Zoonotic transmission of hepatitis E virus (HEV) is of special concern, particularly in high income countries were waterborne infections are less frequent than in developing countries. High HEV seroprevalences can be found in European pig populations. The aims of this study were to obtain prevalence data on HEV infection in swine in Belgium and to phylogenetically compare Belgian human HEV sequences with those obtained from swine. An ELISA screening prevalence of 73% (95% CI 68.8–77.5) was determined in Belgian pigs and a part of the results were re-evaluated by Western blot (WB). A receiver operating characteristic curve analysis was performed and scenarios varying the ELISA specificity relative to WB were analysed. The seroprevalences estimated by the different scenarios ranged between 69 and 81% and are in agreement with the high exposure of the European pig population to HEV. Pig HEV sequences were genetically compared to those detected in humans in Belgium and a predominance of genotype 3 subtype f was shown in both swine and humans. The high HEV seroprevalence in swine and the close phylogenetic relationships between pig and human HEV sequences further support the risk for zoonotic transmission of HEV between humans and pigs.
Induction of an LH surge and ovulation by buserelin (as Receptal) allows breeding of weaned sows with a single fixed-time insemination
Driancourt, M.A. ; Cox, P. ; Rubion, S. ; Harnois-Milon, G. ; Kemp, B. ; Soede, N.M. - \ 2013
Theriogenology 80 (2013)4. - ISSN 0093-691X - p. 391 - 399.
ovarian-function - protein loss - litter size - fertility - estrus - fertilization - performance - interval - swine
The aim of this study was to demonstrate successful breeding of sows with a single fixed-time insemination following ovulation induction by buserelin, a GnRH analogue. In a first step, the optimal dose of buserelin (6, 10, or 16 µg) injected at 77 hours after weaning was determined in weaned sows (N = 15, 11, and 12, respectively) using its ability to induce an LH surge of similar magnitude as in control sows (N = 15) and induce ovulation. In 29/38 treated sows (76%), ovulation was induced and synchronized between 32 and 44 hours after injection, and the proportion of females ovulating during this time window was similar between groups at 73%, 73%, and 83% (6, 10, or 16 µg, respectively). Interestingly, whereas ovulation of 100% multiparous sows was induced and synchronized in the 32 to 44 hours posttreatment time window, successful induction was achieved in a lower proportion of primiparous sows (50%, 50%, and 67% following 6, 10, or 16 µg, respectively), the dose effect being nonsignificant. The magnitude of the LH surge was similar between control and treated sows, irrespective of the buserelin dose injected. Neither ovulation rate nor the number of good embryos on Day 5 postovulation differed between groups. Interestingly, the frequency of follicular cysts at slaughter was significantly affected by treatment (P <0.05), being minimal and maximal in sows treated with 10 or 6 µg buserelin, respectively. In a second step, 419 sows from commercial herds in Spain, Germany, and France were randomly allocated to a control or treated group. The control sows were inseminated twice 12 ± 4 hours apart once estrus was detected. Treated sows received 10 µg buserelin at 86 ± 3 hours after weaning and were inseminated once 30 to 33 hours later. Farrowing rate of treated sows (87%, 166/192) was similar to that of control sows (84.5%, 169/200). Litter size was also similar between treated and control sows (13.6 ± 3.8 vs. 13.7 ± 3.2). In multiparous sows, neither duration of lactation nor magnitude of the fat loss during lactation significantly affected treatment effects. It is concluded that ovulation of weaned multiparous sows can be tightly synchronized by buserelin (10 µg) administration at 86 hours postweaning. This allows breeding once at a fixed time following buserelin injection while maintaining reproductive performance at a level similar to that of sows bred twice during estrus.
The pig's nose and its role in dominance relationships and harmful behaviour
Camerlink, I. ; Turner, S.P. - \ 2013
Applied Animal Behaviour Science 145 (2013)3-4. - ISSN 0168-1591 - p. 84 - 91.
seminatural environment - social recognition - familiarity - aggression - emotions - primates - welfare - odors - swine - touch
Affiliative behaviour may have an essential role in many behavioural processes. Gently nosing between group members occurs in almost all social behavioural processes of pigs (Sus scrofa), but the reasons for its performance are unclear. We examined whether nosing between pigs was related to dominance relationships or harmful behaviours such as manipulation of the tail using 80 crossbred pigs. Both males and females, housed in straw pens, were studied at 8 weeks of age (10 pigs/pen). Dominance ranks were determined by a feed competition test. The behaviour of 64 focal pigs was observed for 2 h per pig in total. Pigs nosed their pen mates on average 36 ± 3 times within 2 h, and nosing behaviour mainly consisted of nose-to-nose contact, nosing the head and nosing the body, rather than nosing the ear, groin, tail or ano-genital region. These gentle pig-directed nosing behaviours, i.e. gently touching another individual with the snout, was here defined as social nosing. Dominance relationships did not influence the amount of nosing given or received. Social nosing was largely unrelated to harmful behaviour. Nosing the tail correlated with tail biting (rs = 0.37), but only 0.3 percent of social nosing was followed by this behaviour. Pigs which delivered much nosing did not receive less aggression, and nor did they receive a heightened amount of nosing in return. We suggest that pigs may nose each other for social recognition, as affiliative behaviour, to gain olfactory signals, or to satisfy an intrinsic need to nose. In conclusion, social nosing in pigs was largely unrelated to harmful behaviours, was not related to dominance relationships and should remain largely unaffected by efforts to minimise harmful behaviours in farming systems
Dynamics of MRSA carriage in veal calves: A longitudinal field study
Graveland, H. ; Wagenaar, J.A. ; Verstappen, K.M.H.W. ; Oosting-van Schothorst, I. ; Heederik, D.J.J. ; Bos, M.E.H. - \ 2012
Preventive Veterinary Medicine 107 (2012)3-4. - ISSN 0167-5877 - p. 180 - 186.
resistant staphylococcus-aureus - methicillin-resistant - escherichia-coli - pig farms - animals - transmission - epidemiology - flora - swine
Colonization of Methicillin-Resistant Staphylococcus aureus (MRSA) in food producing animals has public health implications, but intervention targets have not yet been identified. In this field study occurrence and dynamics of MRSA in veal calves were investigated longitudinally on three farms. Determinants generally associated with MRSA carriage, such as environmental exposure and antimicrobial use, were explored. In addition, the reliability and reproducibility of MRSA detection in nasal samples from veal calves were investigated as well as the additional value of rectal samples to establish MRSA status of an individual animal. On these three farms, MRSA prevalence and MRSA air loads in stables rapidly increased during the production cycle, especially after releasing calves from their individual houses, but not simultaneously with or directly after treatment with antimicrobials. These observations constitute the hypothesis that antimicrobial use may not necessarily be the only condition for MRSA transmission in veal calves, but indicate that other factors may contribute to transmission as well. MRSA in calves was present both nasally and rectally. The reproducibility and repeatability of the nasal samples were moderate. The results of this study give a better understanding of the dynamics of MRSA in a field situation.
Relationship between growth rate and oral manipulation, social nosing, and aggression in finishing pigs
Camerlink, I. ; Bijma, P. ; Kemp, B. ; Bolhuis, J.E. - \ 2012
Applied Animal Behaviour Science 142 (2012)1-2. - ISSN 0168-1591 - p. 11 - 17.
environmental enrichment - breeding programs - fattening pigs - animal-welfare - behavior - performance - swine - oxytocin - emotions - tree
Pigs may affect each other's health, welfare and productivity through their behaviour. The effect of a pig on the growth rate of its pen mates is partly heritable and is referred to as its social genetic effect. Social genetic effects, also known as indirect genetic effects, have been found in a number of livestock breeds, in natural and laboratory populations, and in plant breeding and forestry, and have become an important research topic in recent years. In pigs, social genetic effects are hypothesized to be related to behaviour. The mechanism behind social genetic effects for growth, as well as the relationship between behaviours and growth itself, is largely unknown. To gain insight in the mechanism behind social genetic effects, we investigated the relationship between behaviours and growth rate in pigs. On a commercial pig farm, 398 finishing pigs in 50 pens (eight pigs/pen) were observed at 12 weeks of age using 2-min instantaneous scan sampling for 6 h during daytime. For 324 observed pigs, growth rate during the finishing period was known. The relationship between behaviours and growth rate during the finishing period was analysed with behaviour as explanatory variable in a mixed model. Results show that time spent giving behaviours, like oral manipulation, social nosing, aggression and belly nosing, was not related to own growth rate. Receiving behaviours, however, did relate to growth. Pigs that received more oral manipulation, observed as tail biting, ear biting and paw biting, grew less well (P <0.05). Growth rate was 43 (± 17) g/d lower in pigs that received oral manipulation during more than 2% of the observations as compared to pigs that did not receive oral manipulation. Pigs that received social nosing, a gentle touch or sniff at any part of the body, had a higher growth rate (P <0.05): growth rate differed 29 (± 17) g/d between pigs that received social nosing during more than 2% of observations as compared to not receiving social nosing at all. Receiving aggression and belly nosing, a forceful rubbing of the belly, did not influence growth rate. In conclusion, receiving oral manipulation and social nosing related to growth rate. This suggests that pigs selected for positive social genetic effects for growth may potentially show behavioural changes. Effects of selection for social genetic effects on behaviour and growth will be studied in future research.
Longitudinal study on transmission of MRSA CC398 within pig herds
Broens, E.M. ; Espinosa-Gongora, C. ; Graat, E.A.M. ; Vendrig, N.J. ; Wolf, P.J. van der; Guardabassi, L. ; Butaye, P. ; Nielsen, J.P. ; Jong, M. de; Giessen, A.W. van de - \ 2012
BMC Veterinary Research 8 (2012). - ISSN 1746-6148
resistant staphylococcus-aureus - livestock-associated mrsa - netherlands - prevalence - swine - quantification - carriage - workers - design - virus
Background Since the detection of MRSA CC398 in pigs in 2004, it has emerged in livestock worldwide. MRSA CC398 has been found in people in contact with livestock and thus has become a public health issue. Data from a large-scale longitudinal study in two Danish and four Dutch pig herds were used to quantify MRSA CC398 transmission rates within pig herds and to identify factors affecting transmission between pigs. Results Sows and their offspring were sampled at varying intervals during a production cycle. Overall MRSA prevalence of sows increased from 33% before farrowing to 77% before weaning. Overall MRSA prevalence of piglets was > 60% during the entire study period. The recurrent finding of MRSA in the majority of individuals indicates true colonization or might be the result of contamination. Transmission rates were estimated using a Susceptible-Infectious-Susceptible (SIS-)model, which resulted in values of the reproduction ratio (R0) varying from 0.24 to 8.08. Transmission rates were higher in pigs treated with tetracyclins and ß-lactams compared to untreated pigs implying a selective advantage of MRSA CC398 when these antimicrobials are used. Furthermore, transmission rates were higher in pre-weaning pigs compared to post-weaning pigs which might be explained by an age-related susceptibility or the presence of the sow as a primary source of MRSA CC398. Finally, transmission rates increased with the relative increase of the infection pressure within the pen compared to the total infection pressure, implying that within-pen transmission is a more important route compared to between-pen transmission and transmission through environmental exposure. Conclusion Our results indicate that MRSA CC398 is able to spread and persist in pig herds, resulting in an endemic situation. Transmission rates are affected by the use of selective antimicrobials and by the age of pigs.
Detection and Characterization of Hepatitis E Virus in Domestic Pigs of Different Ages in Portugal
Berto, A. ; Mesquita, J.R. ; Hakze-van der Honing, R.W. van der; Nascimento, R.S. ; Poel, W.H.M. van der - \ 2012
Zoonoses and Public Health 59 (2012)7. - ISSN 1863-1959 - p. 477 - 481.
united-kingdom - swine - infection - england - transmission - prevalence - antibodies - countries - wales - herds
This study represents the primary hepatitis E virus (HEV) surveillance in domestic pigs in Portugal, five pig farms were investigated in 5 different Portuguese regions, ten faecal samples were collected at four different stages of the production. All faecal samples were tested for hepatitis E virus by real-time RT-PCR. At least one sample from each farms of all age groups tested positive for HEV. The prevalence in the pig herds varied from 10% to 30% and the mean prevalence was 32% in weaners, 20% in growers, 32% in fatteners and 4% in adult dry sows. Phylogenetic analysis of the detected HEV sequences indicated that the circulating virus strains belong under the genotype 3.
Transmission dynamics of hepatitis E virus in pigs: Estimation from field data and effect of vaccination
Backer, J.A. ; McCreary, C. ; Martelli, F. ; Poel, W.H.M. van der - \ 2012
Epidemics 4 (2012)2. - ISSN 1755-4365 - p. 86 - 92.
united-kingdom - infection - swine - prevalence - strains - humans - stores - farms - feces - liver
Hepatitis E is a viral disease that causes serious concerns for public health. Hepatitis E virus (HEV) genotype 3 is endemic in commercial pig farms worldwide that act as a reservoir. Pig-to-human transmission may occur when infectious animals enter the food chain at slaughter, through consumption of contaminated meat, direct exposure or use of by-products. To reduce the fraction of infectious animals at slaughter age and thus the risk for public health, it is important to understand the transmission dynamics of HEV in pig populations. In this study, we estimate the transmission rate parameter and mean infectious period of HEV in pigs from field data, using a Bayesian analysis. The data were collected in ten commercial pig herds that are each divided into three different age groups. Two transmission models were compared, assuming that animals are infected either locally by their group mates or globally by any infectious animal regardless of its group. For local and global transmission, the transmission rate parameters were 0.11 (posterior median with 95% credible interval: 0.092–0.14 day-1) and 0.16 (0.082–0.29 day-1), the mean infectious periods were 24 (18–33) days and 27 (20–39) days and the reproduction numbers were 2.7 (2.2–3.6) and 4.3 (2.8–6.9). Based on these results, global transmission is considered to be the more conservative model. Three effects of vaccination were explored separately. When vaccination is not sufficient to eliminate the virus, a shorter mean infectious period decreases the fraction of infectious animals at slaughter age, whereas a reduced transmission rate parameter adversely increases it. With a reduced susceptibility, vaccination of animals at a later age can be a better strategy than early vaccination. These effects should be taken into account in vaccine development
Assessment of liquid chromatography-tandem mass spectrometry approaches for the analysis of ceftiofur metabolites in poultry muscle
Berendsen, B.J.A. ; Stolker, A.A.M. ; Nielen, M.W.F. - \ 2012
Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 29 (2012)2. - ISSN 1944-0049 - p. 197 - 207.
beta-lactam antibiotics - escherichia-coli - bacterial pathogens - kidney tissue - bovine - swine - plasma - desfuroylceftiofur - cattle - milk
The use of cephalosporin antibiotics in veterinary practice is likely to play an important role in the development of ß-lactam-resistant bacteria. To detect off-label cephalosporin antibiotic usage, an analytical method is needed that, besides the native compound, also detects their active metabolites. In this paper, the applicability of three approaches for the quantitative analysis of ceftiofur using LC–MS/MS is assessed, viz. (A) analysis of ceftiofur, desfuroylceftiofur and/or desfuroylceftiofur cystein disulfide, (B) derivatisation of ceftiofur metabolites to desfuroylceftiofur acetamide and (C) chemical hydrolysis using ammonia, to produce a marker compound for ceftiofur. We found that approach A was not suited for quantitative analysis of total ceftiofur concentration or for effectively detecting off-label use of ceftiofur. Approach B resulted in adequate quantitative results, but was considered a single compound method because it depends on cleavage of a thioester group, which is present in only a limited number of cephalosporin antibiotics. Approach C showed adequate quantitative results but, in contrast to approach B, it is applicable to a range of cephalosporin antibiotics. Therefore, it is applicable as a broad quantitative screening of cephalosporin compounds in poultry tissue samples to indicate off-label use of cephalosporins in poultry breeding. Based on this study, it was concluded that approach C is the most suitable to detect off-label use of a range of cephalosporin antibiotics.
Reproductive performance of second parity sows: relations with subsequent reproduction
Hoving, L.L. ; Soede, N.M. ; Graat, E.A.M. ; Feitsma, H. ; Kemp, B. - \ 2011
Livestock Science 140 (2011)1-3. - ISSN 1871-1413 - p. 124 - 130.
swedish yorkshire sows - litter size - genetic-parameters - ovarian-function - protein loss - pigs - efficiency - landrace - swine - productivity
The objective of this study was to determine relations between reproductive performance, i.e. being a repeat breeder and litter size, in 2nd parity and reproductive performance in later parities. In addition, relations between the 1st and 2nd parity litter size and litter size in later parities were determined. First, 184,135 records from 46,571 sows were used to analyze the effect of being a repeat breeder in 2nd parity on subsequent farrowing rate, litter size and parity number at culling. Second, 161,521 records of 39,654 sows were used to analyze the effect of litter size from 1st insemination in 2nd parity, being either low (= 10 piglets total born), medium (11–13) or high (= 14), on subsequent litter size, farrowing rate and parity number at culling, with litter size in 1st parity included in the model as well. In total 15.7% of the sows inseminated in 2nd parity were a repeat breeder in 2nd parity. Being a repeat breeder in 2nd parity did not affect litter size in subsequent parities, however it decreased farrowing rate in parity 3 (4.1%) and 4 (3.4%), but not in later parities (P <0.05). Repeat breeders in 2nd parity were culled on average 2 parities earlier compared with non-repeat breeders (resp. parity 5 vs. 7, P <0.05). Sows with a low litter size in 2nd parity showed a lower litter size in parity 3 and up compared with sows with a medium or high litter size in 2nd parity (P <0.05). The magnitude of this effect, however, decreased if litter size in 1st parity increased. For example, the difference in piglets born in parity 3–5 between sows with a low and high litter size in 2nd parity was - 4.6 piglets for sows with a low litter size in 1st parity. This difference decreased to - 3.3 piglets for sows with a high litter size in 1st parity. Sows with a high litter size in 2nd parity had 2% lower farrowing rate in parity 3, but not in later parities. Sows with a low litter size in 2nd parity were culled 1 parity earlier compared with sows with a medium or high litter size in 2nd parity. This study showed that a large part of the sows with poor reproductive performance in 2nd parity can be expected to have a poor reproductive performance in subsequent parities. The effect of 2nd parity litter size on subsequent litter size, however, depends on 1st parity litter size
Prevalence and risk factor analysis of livestock associated MRSA-positive pig herds in The Netherlands
Broens, E.M. ; Graat, E.A.M. ; Wolf, P.J. van der; Giessen, A.W. van de; Jong, M.C.M. de - \ 2011
Preventive Veterinary Medicine 102 (2011)1. - ISSN 0167-5877 - p. 41 - 49.
resistant staphylococcus-aureus - methicillin-resistant - swine - st398 - transmission - farms - model
In 2005, methicillin-resistant Staphylococcus aureus was found in pig herds and in humans in contact with pigs. To determine the prevalence of, this now-called livestock-associated (LA) MRSA among pig herds in the Netherlands and to identify and quantify risk factors, an observational study of 202 pig herds was performed between 2007 and 2008. Five environmental wipes and 60 nasal swabs from each herd were collected, and microbiological analysis was performed on single environmental samples and pooled nasal samples. A herd was considered MRSA-positive if =1 sample tested positive. The prevalence of MRSA-positive herds was 67% in breeding herds and 71% in finishing herds. Multivariable logistic regression analysis was then performed on data from 171 breeding herds. The number of MRSA-positive herds increased from ~30% at the start to ~75% at the end of the study, most likely due to transmission between herds. The prevalence of MRSA increased with herd size, as ~40% of smaller herds (80% of larger herds (>500 sows). Other risk factors (e.g. antimicrobial use, purchase of gilts and hygiene measures) were not significantly associated with MRSA, though associated with herd size. Herd size appeared to be a compilation of several factors, which made larger herds more often MRSA positive.
Estimation of the Likelihood of Fecal-Oral HEV Transmission Among Pigs
Bouwknegt, M. ; Teunis, P.F.M. ; Frankena, K. ; Jong, M.C.M. de; Rode Husman, A.M. de - \ 2011
Risk Analysis 31 (2011)6. - ISSN 0272-4332 - p. 940 - 950.
hepatitis-e-virus - local grocery stores - rt-pcr assay - united-states - experimental-infection - livers sold - sows feces - swine - japan - inactivation
Sources for human hepatitis E virus (HEV) infections of genotype 3 are largely unknown. Pigs are potential animal reservoirs for HEV. Intervention at pig farms may be desired when pigs are confirmed as a source for human infections, requiring knowledge about transmission routes. These routes are currently understudied. The current study aims to quantify the likelihood of pig feces in causing new HEV infections in pigs due to oral ingestion. We estimated the daily infection risk for pigs by modeling the fate of HEV in the fecal–oral (F–O) pathway. Using parameter values deemed most plausible by the authors based on current knowledge the daily risk of infection was 0.85 (95% interval: 0.03–1). The associated expected number of new infections per day was ~4 (2.5% limit 0.1, the 97% limit tending to infinity) compared to 0.7 observed in a transmission experiment with pigs, and the likelihood of feces causing the transmission approached 1. In alternative scenarios, F–O transmission of HEV was also very likely to cause new infections. By reducing the total value of all explanatory variables by 2 orders of magnitude, the expected numbers of newly infected pigs approached the observed number. The likelihood of F–O transmission decreased by decreasing parameter values, allowing for at most 94% of infections being caused by additional transmission routes. Nevertheless, in all scenarios F–O transmission was estimated to contribute to HEV transmission. Thus, despite the difficulty in infecting pigs with HEV via oral inoculation, the F–O route is likely to cause HEV transmission among pigs.
Investigation of the Efficiencies of Bioaerosol Samplers for Collecting Aerosolized Bacteria Using a Fluorescent Tracer. I: Effects of Non-sampling Processes on Bacterial Culturability
Zhao, Y. ; Aarnink, A.J.A. ; Doornenbal, P. ; Huynh, T.T.T. ; Groot Koerkamp, P.W.G. ; Jong, M.C.M. de; Landman, W.J.M. - \ 2011
Aerosol Science and Technology 45 (2011)3. - ISSN 0278-6826 - p. 423 - 431.
airborne particles - relative-humidity - survival - rotavirus - swine - air - microorganisms - temperature - enumeration - barns
By sampling aerosolized microorganisms, the efficiency of a bioaerosol sampler can be calculated depending on its ability both to collect microorganisms and to preserve their culturability during a sampling process. However, those culturability losses in the non-sampling processes should not be counted toward the sampling efficiency. Prior to the efficiency assessment, this study was designed to investigate the culturability losses in three non-sampling processes: (1) the tracer uranine induced loss; (2) the loss during aerosolization (pre-sampling process); and (3) the bacteria and uranine recovery in air sample handling procedures for the samples of the Andersen 6-stage impactor and the Airport MD8 (post-sampling process). The results indicated that uranine had no significant effect on the culturability of Enterococcus faecalis, Escherichia coli, and Mycoplasma synoviae in suspensions (P > 0.05), but negatively affected the culturability of Campylobacter jejuni (P = 0.01). The culturability of E. faecalis, E. coli, and M. synoviae was not affected by stresses caused by aerosolization (P > 0.05). Only 29% of C. jejuni were still culturable during aerosolization (P = 0.02). In the air sample handling procedures, the four species of bacteria were recovered without significant losses from the samples of the Andersen impactor, but only 33-60% uranine was recovered. E. faecalis, E. coli, and M. synoviae were recovered without significant losses from the samples of the Airport MD8. More C. jejuni was recovered (172%), probably due to multiplication or counting variation. It is suggested that tracer and bacteria should be aerosolized separately when the tracer negatively affects the bacterial culturability. In both pre- and post-sampling processes, losses of bacterial culturability (or multiplication) may occur, which should be taken into account when assessing the efficiencies of bioaerosol samplers.
Transmission of methicillin resistant Staphylococcus aureus among pigs during transportation from farm to abattoir
Broens, E.M. ; Graat, E.A.M. ; Wolf, P.J. van der; Giessen, A.W. van de; Jong, M.C.M. de - \ 2011
The Veterinary Journal 189 (2011)3. - ISSN 1090-0233 - p. 302 - 305.
salmonella-typhimurium - rapid infection - high prevalence - risk-factors - netherlands - mrsa - exposure - workers - swine
The prevalence of methicillin resistant Staphylococcus aureus (MRSA) in pigs at abattoirs is higher than in pigs sampled on farms. This study investigated whether MRSA negative pigs can become MRSA positive during transportation from the farm to the abattoir after exposure to other pigs and environmental sources of MRSA. Nasal swabs were collected from four batches of pigs during loading at the farm, on arrival at the abattoir and after stunning. Environmental wipes were taken from lorries after transporting pigs and from lairages after holding pigs. All pigs (n = 117) tested MRSA negative before transportation. On arrival at the abattoir, 12/117 (10.3%) pigs in two batches tested MRSA positive. In lorries that tested positive after transportation, the prevalence of MRSA positive pigs was 21.1%, whereas no MRSA was detected in pigs that had been transported in lorries that tested negative after transportation. At stunning, all batches and 70/117 (59.8%) pigs tested MRSA positive. Pigs can become MRSA positive in the short period of time during transportation from the farm to stunning at the abattoir
The effects of housing system and feeding level on the joint-specific prevalence of osteochondrosis in fattening pigs
Grevenhof, E.M. van; Ott, S. ; Hazeleger, W. ; Weeren, P.R. van; Bijma, P. ; Kemp, B. - \ 2011
Livestock Science 135 (2011)1. - ISSN 1871-1413 - p. 53 - 61.
leg weakness - finishing pigs - growth-rate - genetic-parameters - production traits - space allowance - slaughter pigs - protein-levels - arthrosis - swine
Osteochondrosis (OC) is seen as the main cause of leg weakness in pigs, leading to welfare problems and economic losses. Environmental factors in pig husbandry, such as the housing system and feeding strategy are expected to influence the prevalence of OC. Therefore, this study investigated the effects of housing system and feeding strategy on the prevalence and severity of OC. In the experiment 345 pigs were used. At an age of 69 days intact boars and gilts were separated and assigned to groups of five or six individuals. A two by two factorial design of housing system and feeding strategy was applied. The housing system was either a conventional concrete floor partial slatted, or a deep litter floor with extra space allowance. The feeding strategy was either ad libitum or restricted to 80% of ad libitum. Pigs were slaughtered at the age of 161–176 days. In total, five joints of the left front and hind limbs were macroscopically assessed for OC on a five-point scale, ranged from no OC through (semi-)loose cartilage fragments. The prevalence of OC in the experimental population was 41.4%, and 12.4% of the individuals had severe lesions. The tarsocrural joint was most affected (30.2%) by OC. OC scores between the different joints were not correlated. Medial sections of joints were most affected (63–100%). Boars were more affected than gilts in the elbow joint. Conventionally housed pigs were more affected than deep litter housed pigs. Ad libitum fed pigs had more OC than restrictedly fed pigs. OC was most prevalent with 57.5% in the pigs on the conventional floor with ad libitum feeding. OC was least prevalent with 33.7% in pigs kept in deep litter housing with restricted feeding. The sex, housing system and feeding strategy did not affect OC in the femoropatellar, metacarpophalangeal, and metatarsophalangeal joints. Our results demonstrate that the OC prevalence can be reduced by applying deep litter floors with extra space allowance and/or restricted feeding in fattening pigs
Circulation of Group 2 Coronaviruses in a Bat Species Common to Urban Areas in Western Europe
Reusken, C.B.E.M. ; Lina, P.H.C. ; Pielaat, A. ; Vries, A. de; Dam-Deisz, C. ; Adema, J. ; Drexler, J.F. ; Drosten, C. ; Kooi, E.A. - \ 2010
Vector-Borne and Zoonotic Diseases 10 (2010)8. - ISSN 1530-3667 - p. 785 - 791.
acute respiratory syndrome - chinese horseshoe bats - sequence - prevalence - diversity - humans - virus - swine
Fecal samples of 211 bats representing 13 different bat species from 31 locations in the Netherlands were analyzed for the presence of coronaviruses (CoV) using a genus-wide reverse transcription (RT)-polymerase chain reaction. CoVs are known for their high potential for interspecies transmission, including zoonotic transmission with bats as reservoir hosts. For the first time, a group 2 CoV was found in a bat, Pipistrellus pipistrellus, in Europe. This is of particular interest for public health as the reservoir host is a species that is common to urban areas in most of Europe and notorious for its close interactions with humans. Four verspertilionid bat species were found to excrete group 1 CoVs, viz. Myotis daubentonii, M. dasycneme, P. pipistrellus, and Nyctalus noctula. The last species is a newly identified reservoir. The overall prevalence was 16.9% and positive bats were found at multiple widespread locations. The circulating group 1 CoV lineages were rather species associated than location associated.
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