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Outbreaks of Classical Swine Fever (CSF) occurred in spring 2006 in Germany close to the Dutch border. On 6th April Dutch pig farmers were given the possibility to submit blood samples directly via their veterinary practitioner to the National Reference Laboratory for CSF if their pigs had non-specific clinical symptoms or if pigs were being treated with antibiotics. The pig farm was not quarantined and was not visited by the veterinary authorities. Over a period of 9 weeks 156 pig farmers submitted whole blood samples via 50 different veterinary practices. All samples tested negative in the PCR test. These pig farmers and veterinary practitioners were asked to respond to a postal questionnaire with questions regarding their experience with this new diagnostic possibility, the distribution of the costs involved, a comparison with other instruments, such as official notification or use of a leukocyte count test, and their knowledge of clinical signs of CSF. 65 pig farmers (42%) and 33 veterinary practices (66%) returned the questionnaire. The main results indicated that pig farmers (72%) would use this type of exclusion diagnostics sooner than that they would approach the veterinary authorities (practitioners: 86%). Moreover the respondents considered the fact that the farm was not quarantined immediately to be an advantage (pig farmers, 79%; practitioners, 88%). 32 percent of the pig farmers were not aware that they were required to submit blood samples if pigs were being treated with antibiotics (practitioners: 11%). The majority of pig farmers and practitioners were not satisfied with the current distribution of the costs involved: in their opinion the costs of the PCR test, the costs of the veterinary practitioner and the costs for shipping the samples to the reference laboratory should be paid out of the Animal Health Fund (50% government and 50% industry) or by the government. If the current distribution of the costs is not changed, a large proportion of the pig farmers indicated that they would not use this form of exclusion diagnostics for CSF in the future. Pig farmers appeared to have a rather limited knowledge of the clinical signs of CSF: 33% of the pig farmers could mention maximally three clinical signs of CSF, and 7% could not mention a single clinical sign of CSF and said they were entirely dependent on the practitioners' ability to judge a CSF-suspect situation.

Potential risk factors for clinical signs of post-weaning multisystemic wasting syndrome (PMWS) and porcine dermatitis and nephropathy syndrome (PDNS) in pigs in the Netherlands were investigated in a matched case-control study using a questionnaire (personal interview). Eighty-two pig farmers were questioned about management, hygiene, husbandry systems, disease history, and preventive health care. In this study, 30 pig herds with (cases) and 30 pig herds without (controls) characteristic clinical signs of PMWS were compared. For PDNS, 11 pig herds with (cases) and II pig herds without (controls) characteristic clinical signs of PDNS were compared. Univariate analysis (P < 0.10) showed that the following occurred relatively more often in the PMWS case herds than in the control herds: 1) clinical signs of PDNS, porcine reproductive and respiratory syndrome (PRRS), porcine parvovirus (PPV) infections, meningitis, coccidiosis, and pre-weaning diarrhoea observed by the farmer; 2) vaccination against PRRS and mycoplasma; 3) non-optimal climatic conditions in the nursery rooms, a large variation in weaning age, a high occurrence of cross-fostering of piglets, a large number of sows with lactation problems, poor colostrum intake by piglets; and 4) (historical) use of breeding stock (including semen for artificial insemination) of Anglo-Saxon origin. In the final multivariate statistical model, one variable remained significantly associated with PMWS case herds, namely, the presence of clinical signs of PRRS (and/or the associated use of vaccination against PRRS). It should be noted that in almost all cases animals were vaccinated against PRRS because of clinical signs of PRRS that appeared a few months after the first occurrence of clinical signs of PMWS. This excludes PRRS vaccination as a primary factor in causing PMWS. Analysis of the PDNS case-control data showed comparable results with those of the PMWS study. In the final statistical model, the presence of clinical signs of PRRS (and/or the associated use of vaccination against PRRS) was significantly associated with PDNS case herds.

Encephalomyocarditis virus (EMCV) has been found on pig farms worldwide and can cause myocarditis in young pigs and reproduction disorders in sows. So far, clinical signs of EMCV have not been reported in the Netherlands. The aim of this study was to estimate the seroprevalence of EMCV infection in Dutch sow herds. A total of 277 Dutch sow herds were randomly selected, from which 3237 serum samples were collected. These samples were tested for EMCV antibodies using the virus neutralization test (VN test). The apparent prevalence of EMCV antibodies was 9.3% in the total sow population, and the apparent herd prevalence was 58.8%. An exact determination of the prevalence of EMCV infections in the Dutch sow population was not possible because the characteristics of the VN test under field circumstances were not known. However, Dutch sow herds seem to be infected with EMCV because the distribution of positive blood samples in the tested sow population was significantly different from that expected if random false-positive reactions had occurred.

In a randomized, confirmatory study performed between July and October 2000 the efficacy of two iron products in preventing iron deficiency anaemia was compared. A total of 102 newborn piglets from ten litters were treated intramuscularly with 200 mg iron as iron dextran per ml, or 200 mg iron as gleptoferron per ml. For true comparison, piglets within a litter of a sow were subdivided into pairs on the basis of birth weight (one pair of the two heaviest piglets, et cetera). Within a pair, treatment with the iron supplements was randomly allocated. One group of piglets was injected at an age of 1 day (experiment 1) and the other group of piglets was injected at an age of 3 days (experiment 2). The piglets were weighed and blood samples were taken at an age of 18 days (experiment 1) or at an age of 19 days (experiment 2). Average daily weight gain and haemoglobin concentrations of both treatment groups were compared. Both products were very effective in preventing anaemia. No significant differences could be found between the two formulations. It can be concluded that iron-dextran and gleptoferron can be used with similar effect for anaemia prevention in piglets.

Within the framework of a sero-monitoring system, in operation since 1996. blood samples from wild boar shot during the hunting seasons 1999-2000 and 2000-2001 in The Netherlands were screened for the presence of antibodies against classical swine fever virus (CSFV), swine vesicular disease virus (SVDV), and Anjeszky's disease virus (ADV). The results indicate that CSFV, SVDV, and ADV are uncommon in the wild boar population in the Netherlands. Because of the recent foot-and-mouth disease (FMD) epidemic in the Netherlands in 2001, blood samples (approximately 200 samples) from wild boar shot in the Netherlands during the hunting season 2001/2002 were examined for antibodies against FMD. To date, antibodies against FMD have not been detected.

Mites can be important sources of airborne allergens, especially on farms. Two dust samples from pig farms and three dust samples from poultry farms were investigated for mites. House-dust mites were present in the poultry-dust samples, but not in the pig-dust samples. Furthermore, storage mites and predatory mites also were found in the poultry-dust samples. Specifically, the house-dust mite Dermatophagoides evansi was found in the dust samples from two poultry farms. Subsequently, a dust sample was collected from five other poultry farms. Again, D. evansi was present in dust from these farms. This is the first time that D. evansi is reported in dust from poultry farms in Western Europe outside Norway. If D. evansi cross-reacts with other Dermatophagoides spp., then poultry farmers and their families, but also other professionals working in the poultry industry, such as veterinarians, may be exposed to house-dust mites with potential clinical consequences, both domestic and occupational.

In this paper we describe a study of the use of the white blood cell count (wbcc) as a parameter for detecting outbreaks of Classical Swine Fever (CSF). Meta-analysis of the results of challenge experiments revealed that oronasal infection of SPF-pigs with the virulent CSF virus (CSFV) strains Brescia or NL9201 resulted in a significant decrease in the average white blood cell count during the first week after inoculation of the virus. Challenge of conventional finishing pigs and sows with the moderately virulent strain Paderborn also resulted in a significant decrease in the average wbcc. However, this decrease was not observed after inoculation of SPF pigs with the mildly virulent CSFV strains Henken, Zoelen, or Bergen. The usefulness of clinical inspection in combination with wbcc to detect CSF outbreaks in the field was examined using the results of 214 EDTA blood specimens collected from 22 infected herds and 7250 EDTA blood specimens collected from 1450 non-infected herds. Half of the infected herds had been infected with the moderately virulent CSFV strain Venhorst (closely related to strain Paderborn) during the 1997-98 epidemic in the Netherlands. The other half had been infected with the moderately virulent CSFV strain Loraine. Using these data as a starting point, 1000 samples of one to ten specimens were generated by Monte Carlo simulation. These simulated samples and the samples of the non-infected herds were analysed by use of Receiver Operating Characteristic curves. On the basis of that analysis, the optimal number of animals whose wbcc needed to be determined to detect a CSF outbreak was five. With this number of animals, in conjunction with the threshold of 8000 white blood cells per mm3 (meaning that a herd is designated as CSF suspect if one or more of the five specimens has a white blood cell count of 8000 leukocytes/mm3 or less), the test procedure had a herd sensitivity (HSE) of 94.5% and a herd specificity (HSP) of 97.2%). The HSE is defined as the percentage of samples of infected herds with a positive result of the test procedure; HSP is defined as the percentage of uninfected herds with a negative result of the test procedure. We conclude that the wbcc can help the veterinary practitioner to detect outbreaks of CSF caused by (moderately) virulent CSFV strains. However, for the detection of outbreaks caused by mildly virulent CSFV strains, the contribution of the wbcc is doubtful. Development of additional tools that can improve the clinical diagnosis of the veterinary practitioner remains desirable.

The effect of Stellamune Mycoplasma vaccine, administered to piglets aged 2-15 days and then 13-15 days later, on daily weight gain, energy conversion, and use of medication was examined in fattening pigs on a chronically Mycoplasma hyopneumoniae infected pig farm. Half of the piglets were vaccinated and the other half acted as controls. In the study design, half of the pens in the fattening unit were allocated to vaccinated pigs; the other half to non-vaccinated pigs, pen was the experimental unit. In the fattening pens sows and castrated boars were separated. The study consisted of a total of 37 pens with vaccinated, and 37 pens with non-vaccinated pigs in 12 different compartments within the pig herd. In the finishing period, mean growth performance and mean energy conversion (EV/kg) of vaccinated animals was 65 grams/day higher and 0.07 EV/kg lower than in control pigs. Furthermore, the incidence of individual curative medication against respiratory problems was more than 4 times higher in control pigs than in vaccinated pigs. There was a tendency for a higher number of group medications against respiratory problems in control pigs than in vaccinated pigs. It is concluded that, in this herd, vaccination against M. hyopneumoniae was successful from an economic point of view.

During the hunting season 1996-1999, blood samples were collected from wild boar shot in The Netherlands. Sera were screened for presence of antibodies against classical swine fever virus (CSFV), swine vesicular disease virus (SVDV), Aujeszky's disease virus (ADV), and Trichinella spiralis. The results indicate that CSFV, SVDV, and ADV are uncommon in the wild boar population. Therefore, it seems that CSFV, SVDV, and ADV infection in the wild boar population is not an important reservoir in The Netherlands. ADV and CSFV infections are endemic in the wild boar population in Germany. Since contact between the German and Dutch wild boar populations can not be excluded, continuation of the sero-surveillance system seems appropriate. In the decade before 1998, the wild boar population in The Netherlands seemed to be free of T. spiralis. Whether the finding, in the hunting season of 1998-1999, of a few wild boar with antibodies against T. spiralis is an artefact or not, should be investigated in further research.

Various new developments confront livestock production, in which certification, monitoring and surveillance of animal health are becoming major items. In that respect serum banks can be a helpful epidemiological tool to provide valid data for decisions on prevention and eradication of disease. History, aims and use of serum banks and storage and freezing conditions are discussed. A plea is made to create serum banks for different animal species in the Netherlands.

Oesophagogastric lesions are a worldwide problem in swine. After extensive research in the 1960s, with primarily indications for a relationship with nutrition, no new reports were published for a long time. Recently, oesophagogastric lesions in swine have come to the centre of attention again, because there are indications for an increase in the prevalence of oesophagogastric lesions, and in particular ulcers, in swine. Therefore recent advances in the field are reviewed. The pathogenesis, prevalence, risk factors and economic consequences of oesophagogastric lesions are discussed.

This article presents a survey of death-causes of all spontaneously died pigs, n = 851, from a restricted area in the province of South Holland during a 2 1/2 months lasting hog-cholera epizoötic in 1992. 23 pigs from 5 submissions showed a positive IFT against hog-cholera virus. Those animals and pigs from sero-positive farms were excluded from this survey. The results of the post-mortems were compared with the post-mortem findings of the normally submitted, selected, animals in 1991 and 1992, n = 904 + 745, from the western parts of the Netherlands, in which the above mentioned province is situated. By means of classification of the animals in age-classes and of the post-mortem findings to disease or diseased organsystem, insight is gained in the prevalence of the various causes of death per age-class. No distinct differences were found between the findings in the groups of animals from 1991 and 1992. In the group of the hog-cholera-period comparatively more animals belonged to the neonatal and suckling period. In contrast to 1991-1992 the number of weaned and fattening pigs in the hog-cholera-group was lower. In both groups 40% of the death-causes was due to diseases of the digestive tract and 30% was a result of respiratory-tract infections. The third main cause of death in both groups was septicaemia and related diseases as endocarditis, pleuritis, peritonitis, polyserositis and polyarthritis. Comparison of the prevalence of infectious diseases per organsystem in successive age-classes demonstrated a similar tendency in the hog-cholera-group as in the year-groups 1991 and 1992.(ABSTRACT TRUNCATED AT 250 WORDS)

As no systematic study has been done to get an accurate estimate of the incidence of return to oestrus after first insemination in sows in the Netherlands, the objectives of this investigation were: 1) to obtain an estimate of the incidence of return to oestrus after insemination at the herd level; 2) to investigate the association between incidence of return to oestrus after first insemination and reproduction characteristics to get an impression of the economic importance. These objectives were investigated using the reproduction results of 240 swine breeding herds in The Southern Netherlands in 1987, using their CBK plus computerized herd management records. The average incidence of return to oestrus after first insemination on a herd level was 16.9 per 100 first inseminations. An increase of incidence with 10 returns per 100 first inseminations, corrected for confounders in a multiple linear regression model, was associated with a decrease of approximately 0.3 liveborn piglets/sow/year. Thereupon individual sows were followed in 1988 and 1989 prospectively in 37 sow herds from weaning to insemination, returning to oestrus or not after first insemination to farrowing. The investigation focused in particular on the relationship between returning to oestrus after first insemination and incident infection with porcine parvovirus (PPV) and Leptospira interrogans serovar bratislava (L. bratislava). During a number of consecutive farm visits sows were blood sampled at weaning and again a blood sample was taken 6 weeks later. The final dataset that was analysed consisted of 161 animals that did not return to oestrus after first insemination and 158 animals that returned to oestrus after first insemination.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibody titres against Aujeszky's disease virus (ADV) in the plasma of slaughter pigs were compared with respect to the site of sampling, namely on the farm (one day before delivery to the slaughterhouse) and in the slaughterhouse during slaughter. No significant differences were noted in the antibody titres against ADV with respect to the different sampling sites. Blood samples collected at the slaughterhouse can be used for monitoring and surveillance systems within the framework of organised pig health care.

During an Integrated Quality Control (IQC) project for finishing pigs, the application of veterinary drugs was registered by means of a logbook on 75 pig finishing farms. Investigated is as to how far the application of veterinary drugs to animals is linked up with clinical observations, management and climatic conditions on the farm and to what extent the application of veterinary drugs is linked up with the occurrence of pathological findings in pigs at the slaughterhouse. The results indicate that more veterinary drugs are used as there are more clinical findings on a pig farm. This is particularly true for the autumn-winter period. Farms that use more veterinary drugs have a higher percentage of pigs with pathological findings at the slaughterhouse. As the point of time of treatment of respiratory disorders is closer to the slaughter date, there is a higher percentage of pigs suffering from pneumonia at the slaughterhouse. Farms treating pigs in the first thirty days of the finishing period against intestinal disorders have a distinct higher percentage of pigs suffering from pneumonia at the slaughterhouse. It appears that less veterinary drugs are used at farms having specific housing and management characteristics.

Log book recording was done for twelve months on approximately 100 pig finishing farms in an Integrated Quality Control (IQC) project. This recording was designed to gain a better understanding of the extent and nature of the medication and vaccination on these farms. Vaccination against Aujeszky's disease was done on the majority of farms. This vaccination mainly consisted in a single, frequently intramuscular, injection. Vaccinations against swine influenza and infections due to Actinobacillus (Haemophilus) pleuropneumoniae were merely sporadic. The animals were dewormed in 58 per cent of the finishing periods, whereas they were given preventive treatment for sarcoptic mange in 23 per cent of the finishing periods. Not a single pig was treated with antibiotics and/or chemotherapeutic agents in 12.5 per cent of the finishing periods. The majority of finishing periods in which treatment was not carried out, were those having closed pig herds. To the extent that the farms were supplied with piglets by more breeders, there were fewer finishing periods during which treatment was omitted. The great majority of cases in which individual therapy was given, were treated for respiratory disorders. On 27 per cent of the farms, more than 10 per cent of the animals per finishing period were treated for respiratory disorders. Group medication was much less frequent: intestinal disorders did not have to be treated on 31 per cent of the farms, and 16 per cent did not require treatment for respiratory disorders. In the great majority of cases in which group treatment was required, this was given during the first sixty days of the finishing period. In view of the fact that there are marked differences in the degree to which pigs have to be medicated on the farms, recording the use of veterinary drugs on farms, could fulfil the function of a signal. On the basis of these signals, measures may be suggested in herd management programmes to ensure an effective and minimum use of veterinary drugs. Using a log book will also enable the pig farmer to estimate whether groups of animals may be sent to the slaughter-house without involving risks to public health.