Physiological indicators of stress and meat and carcass characteristics in tail bitten slaughter pigs

Background

Tail biting is a common welfare problem in pig production and in addition to being a sign of underlying welfare problems, tail biting reduces welfare in itself. The aim of this study was to evaluate the effects of tail biting on different pre and post mortem indicators of stress in slaughter pigs and on carcass and meat characteristics. A total of 12 tail bitten (TB) and 13 control (C) pigs from a farm with a long-term tail biting problem were selected for salivary cortisol analyses before and after transport to the slaughterhouse. After stunning, samples were taken for the analysis of serum cortisol, blood lactate, intestinal heat shock protein 70 (HSP70), and meat quality characteristics. In addition, body temperature immediately after and muscle temperature 35 min after stunning were measured, as well as lean meat percentage and carcass weight.

Results

TB pigs showed a lower cortisol response to the transport-induced stress than C pigs and also had a lower serum cortisol concentration after stunning. HSP70 content in the small intestine was higher in the TB pigs than in C pigs. TB pigs had a considerably lower carcass weight therefore produced a lower total amount of lean meat per carcass than C pigs.

Conclusions

This study suggests that prolonged or repeated stress in the form of tail biting causes a blunted stress response, possibly a sign of hypocortisolism. In addition, it underlines the importance of reducing tail biting, both from an animal welfare and an economic point-of-view.     

The index herd with PMWS in Sweden: Presence of serum amyloid A,circovirus 2 viral load and antibody levels in healthy and PMWS-affected pigs

Background

Postweaning Multisystemic Wasting Syndrome (PMWS) is an emerging disease in pigs of multifactorial origin, but associated to porcine circovirus type 2 (PCV2) infection. PMWS was first diagnosed in Sweden at a progeny test station that received pigs aged five weeks from 19 different nucleus herds on the day after weaning. The objective of this study was to examine, for the first time in an index outbreak of PMWS, the relationship between PCV2 virus, antibodies to PCV2 and serum amyloid a (SAA) in sequentially collected serum samples from pigs with and without signs of PMWS.

Methods

Forty pigs of the last batch that entered the station at a mean age of 37.5 days were monitored for signs of PMWS during the first 55 days after arrival. Serum was collected on six occasions and analysed for presence of PCV2 DNA and antibodies to PCV2, as well as for levels of SAA.

Results

Four of the pigs (10%) were concluded to have developed PMWS, with necropsy confirmation in three of them. These pigs displayed low levels of maternal antibodies to PCV2, more than 10⁷ PCV2 viral DNA copies per ml serum and failed to mount a serological response to the virus. Starting between day 23 and 34 after arrival, an increase in PCV2 viral load was seen in all pigs, but PCV2 did not induce any SAA-response. Pigs that remained healthy seroconverted to PCV2 as the viral load was increased, regardless of initially having low or high levels of PCV2-antibodies.

Conclusion

In this index case of PMWS in Sweden, pigs affected by PMWS were not able to mount a relevant serum antibody response which contributed to the disease progression. The maximal PCV2 virus load was significantly higher and was also detected at an earlier stage in PMWS-affected pigs than in healthy pigs. However, a viral load above 10⁷ PCV2 DNA copies per ml serum was also recorded in 18 out of 34 pigs without any clinical signs of PMWS, suggesting that these pigs were able to initiate a protective immune response to PCV2.     

Seroprevalence of Hepatitis E virus infection in the Irish pig population

Background

Hepatitis E is an acute viral disease of humans, occurring in explosive outbreaks in the developing world and as sporadic cases in returning travellers. Increasing recognition of indigenous transmission in Western countries suggests a zoonotic source of infection, most likely pigs. To determine if hepatitis E virus is present in Irish pigs, sera from 330 animals were examined for antibodies using a commercially available ELISA.

Findings

Antibodies were detected in 89 pigs (27%) in 13 herds (81%).

Conclusions

Hepatitis E virus is present in most Irish pig herds and in many animals within these herds.     

Lumbo-sacral epidural anaesthesia as a complement to dissociative anaesthesia during scrotal herniorrhaphy of livestock pigs in the field

Background

In Sweden, scrotal or inguinal herniorrhaphy of livestock pigs in the field has traditionally been an important part of the surgical skills training of veterinary students. Few substances meet the legal requirements for field anaesthesia of production animals in the European Union but a protocol based on azaperone-detomidine-butorphanol-ketamine does. Unfortunately the anaesthesia is characterised by unpredictable duration and depth and of abrupt awakenings which is not acceptable from an animal welfare perspective and impedes surgical training. Lumbo-sacral epidural analgesia is proven to provide sufficient analgesia to allow abdominal surgery, but there are few reports on the field use of this loco-regional technique. The study aim was to evaluate whether lumbo-sacral anaesthesia can be safely and successfully used in the field by a veterinary student and whether the combination of dissociative and lumbo-sacral epidural anaesthesia improves analgesia and anaesthesia to guarantee animal welfare during herniorrhaphy in livestock pigs, enabling surgical skills training.

Results

Pigs in the control-group (placebo) responded significantly stronger to surgery, with five out of 11 requiring additional doses of detomidine and ketamine. There were no significant differences between groups in respiratory rate, heart rate, blood pressure, SpO₂ or blood gases. SpO₂ levels <94 % were recorded in several pigs in both groups. No post-injection complications were reported at follow-up.

Conclusions

The results from this study showed that lumbo-sacral epidural anaesthesia with lidocaine could successfully be administered during dissociative anaesthesia of livestock pigs by a veterinary student and without reported post-injection complications. It improved analgesia and anaesthesia during herniorrhaphy of sufficient duration to enable surgical skills training. The risks and consequences of hypoxaemia and hypoventilation should be considered.     

A study on the applicability of implantable microchip transponders for body temperature measurements in pigs

Background

The applicability of an electronic monitoring system using microchip transponders for measurement of body temperatures was tested in 6-week-old conventional Danish weaners infected with classical swine fever virus (CSFV). Subcutaneous tissue temperatures obtained by the implantable transponders were compared with rectal temperatures, recorded by a conventional digital thermometer.

Methods

In a preliminary study, transponders were inserted subcutaneously at 6 different positions of the body of 5 pigs. The transponders positioned by the ear base provided the best correlation to rectal temperature. To test the stability of the monitoring system in a larger group of pigs, transponders were therefore inserted by the left ear base in a subsequent infection experiment with 30 pigs.

Results

Generally, the microchip transponders measured a subcutaneous tissue temperature, which was about 1°C lower than the rectal temperature. However, a simple linear relationship between the measures of the two methods was found.

Conclusions

Our study showed that the tested body monitoring system may represent a promising tool to obtain an approximate correlate of body temperatures in groups of pigs. In contrast, however, the tested system did not constitute a suitable tool to measure body temperatures of individual animals in the present pig infection experiment.     

Increasing daily feeding occasions in restricted feeding strategies does not improve performance or well being of fattening pigs

Background

The natural feeding behaviour of the pig is searching for feed by rooting activities throughout the day; self-feeding pigs randomly space their eating and drinking periods throughout the day consuming ten to twelve meals per day. Pigs in conventional fattening pig production are normally fed 2–3 times daily with the feed consumed within 15 minutes. The aim of this study was to determine if more frequent feedings could improve the performance of conventionally kept fattening pigs.

Methods

The experiment was carried out on 360 fattening pigs (27–112 kg live weight), weighed and assigned to pens stratified by weight and sex. Each treatment group consisted of 180 pigs, allocated to 20 pens with nine pigs in each pen. To evaluate how more feeding occasions affects performance and well-being the pigs were divided into two groups and fed three (control group) or nine (treatment group) times daily. The same total amount of liquid feed was fed to each group and the feed ration was correlated to the live weight of the pigs. All weight and slaughter recordings were made individually and recordings of feed consumption were made pen-wise. At slaughter the stomach of each pig was examined for lesions in the pars oesophagea and scored on a scale from 1–6.

Results

Frequent feeding occasions influenced both performance and status of gastric lesions of the pigs adversely. Pigs in the treatment group grew slower compared to pigs in the control group; 697 g/day (± 6.76) versus 804 g/day (± 6.78) (P < 0.001) with no difference in within-pen variation. There was also a lower prevalence of gastric lesions within pigs in the control group (2.4 (± 0.12) compared to 3.0 (± 0.12) (P < 0.01)). There was a positive correlation between gastric lesions in the treatment group and daily weight gain (r = 0.19; P < 0.01).

Conclusion

Increased daily feeding occasions among group housed pigs resulted in a poorer daily weight gain and increased mean gastric lesion score as compared with pigs fed three times daily. This may be a consequence of more frequently occurring competition for feed in the treatment group. The present study does not support increased daily feeding occasions in fattening pigs.     

Direct and indirect transmission of four Salmonella enterica serotypes in pigs

Background

Feed-borne spread of Salmonella spp. to pigs has been documented several times in recent years in Sweden. Experiences from the field suggest that feed-associated serotypes might be less transmittable and subsequently easier to eradicate from pig herds than other serotypes more commonly associated to pigs. Four Salmonella serotypes were selected for experimental studies in pigs in order to study transmissibility and compare possible differences between feed-assoociated (S Cubana and S Yoruba) and pig-associated serotypes (S Derby and S Typhimurium).

Methods

Direct contact transmission was studied in four groups of pigs formed by six 10-week-old salmonella negative pigs commingled with two fatteners excreting one of the four salmonella serotypes. Indirect transmission was studied by putting six 10-week-old salmonella negative pigs in each of four salmonella contaminated rooms. Each room had previously housed a group of pigs, excreting one of the four selected serotypes.All pigs were monitored for two weeks with respect to the faecal excretion of salmonella and the presence of serum antibodies. At the end of the trial, eight samples from inner tissues and organs were collected from each pig at necropsy.

Results

In the four direct transmission groups, one pig shed Salmonella (Cubana) at one occasion. At necropsy, S Typhimurium was isolated from one pig.In the indirect transmission groups, two pigs in the Yoruba room and one pig in each of the other rooms were excreting detectable levels of Salmonella once during the study period of two weeks. At necropsy, S Derby was isolated from one of six pigs in the Derby room and S Typhimurium was isolated from four of the six pigs in the Typhimurium room.No significant serological response could be detected in any of the 48 pigs.

Conclusions

These results show that all four selected serotypes were able to be transmitted in at least one of these field-like trials, but the transmission rate was low in all groups and no obvious differences between feed-associated and pig-associated serotypes in the transmission to naïve pigs and their subsequent faecal shedding were revealed. However, the post mortem results indicated a higher detection of S Typhimurium in the ileocecal lymph nodes of pigs introduced into a contaminated environment in comparison with the other three serotypes.     

Clinical and biochemical changes in 53 Swedish dogs bitten by the European adder - Vipera berus

Background

Every year many dogs in Sweden are bitten by Vipera berus, the only venomous viper in Sweden. This prospective study investigated clinical signs, some biochemical parameters, treatment, and progress of disease after snakebite in 53 dogs. Effects of treatment with and without glucocorticoids were evaluated.

Methods

All fifty-three dogs bitten by Vipera berus were examined the same day the dog was bitten and the next day. Two more examinations during 23 days post snake bite were included. Creatinine, creatine kinase (CK), alanine aminotransferase (ALT), glutamate dehydrogenase (GLDH), alkaline phosphatase (ALP) and bile acid results were followed through 3 to 4 samplings from 34 of the dogs.

Results

All dogs had variable severity of local swelling in the bite area and 73 per cent had affected mental status. Initial cardiac auscultation examination was normal in all dogs, but six dogs had cardiac abnormalities at their second examination, including cardiac arrhythmias and cardiac murmurs. All dogs received fluid therapy, 36 dogs were given analgesics, 22 dogs were treated with glucocorticoids, and ten dogs were treated with antibiotics. Evidence of transient muscle damage (increased CK) was seen one day after the snake bite in 15 (54%) of 28 sampled dogs. Moderate changes in hepatic test results occurred in 1 dog and several dogs (22 of 34) had transient, minor increases in one or more hepatic test result. No dog died during the observation period as a consequence of the snake bite.

Conclusions

Snake bite caused local swelling in all dogs and mental depression of short duration in most dogs. Some dogs had transient clinical signs that could be indicative of cardiac injury and some other had transient biochemical signs of liver injury. Treatment with glucocorticoids did not have any clear positive or negative effect on clinical signs and mortality.     

Field experience with two different vaccination strategies aiming to control infections with Actinobacillus pleuropneumoniae in a fattening pig herd

Background

The prevalence of pleurisies recorded at slaughter is increasing in Sweden, and acute outbreaks of actinobacillosis that require antimicrobial treatments have become more frequent. As an increased use of antimicrobials may result in the development of antimicrobial resistance it is essential to develop alternative measures to control the disease. Vaccinations present an appealing alternative to antimicrobial treatments. The aim of this work was to evaluate the potential of two different vaccination strategies in a specialized fattening herd affected by actinobacillosis.

Methods

The study was conducted in a specialized fattening herd employing age segregated rearing in eight units. The herd suffered from infections caused by Actinobacillus pleuropneumoniae serotype 2, confirmed by necropsy and serology. The study included 54 batches of pigs grouped into five periods. Batches of pigs of the second period were vaccinated against actinobacillosis twice, and pigs in the fourth period were vaccinated three times. Batches of pigs of the first, third and fifth period were not vaccinated. Concentrations of serum antibodies to A. pleuropneumoniae and serum amyloid A (SAA) were analysed and production data were recorded.

Results

Despite vaccinating, medical treatments were required to reduce the impact of the disease. The mean incidence of individual treatments for respiratory diseases during the rearing period ranged from 0 to 4.7 ± 1.8%, and was greatest during the triple vaccination period (period IV; p < 0.05 when compared to other groups). A large proportion of the vaccinated pigs seroconverted to A. pleuropneumoniae serotype 2 in the absence of a SAA-response. The prevalence of pleuritis decreased from 25.4 ± 6.5% in the first period to 5.0 ± 3.7% in the fifth period (p < 0.001).

Conclusions

The vaccine did not effectively prevent clinical expression of A. pleuropneumoniae infections, but seroconversion to A. pleuropneumoniae in the absence of a SAA-response in a large number pigs indicated that the vaccine had activated the immune system. Further, the prevalence of pleuritis decreased with time. This indicates that vaccinations together with intensified medical treatments of affected pigs could be useful in reducing the impact of A. pleuropneumoniae serotype 2 infections.     

Evaluation of a blocking ELISA for the detection of antibodies against Lawsonia intracellularis in pig sera

Background

Lawsonia intracellularis is a common cause of chronic diarrhoea and poor performance in young growing pigs. Diagnosis of this obligate intracellular bacterium is based on the demonstration of the microbe or microbial DNA in tissue specimens or faecal samples, or the demonstration of L. intracellularis-specific antibodies in sera. The aim of the present study was to evaluate a blocking ELISA in the detection of serum antibodies to L. intracellularis, by comparison to the previously widely used immunofluorescent antibody test (IFAT).

Methods

Sera were collected from 176 pigs aged 8-12 weeks originating from 24 herds with or without problems with diarrhoea and poor performance in young growing pigs. Sera were analyzed by the blocking ELISA and by IFAT. Bayesian modelling techniques were used to account for the absence of a gold standard test and the results of the blocking ELISA was modelled against the IFAT test with a "2 dependent tests, 2 populations, no gold standard" model.

Results

At the finally selected cut-off value of percent inhibition (PI) 35, the diagnostic sensitivity of the blocking ELISA was 72% and the diagnostic specificity was 93%. The positive predictive value was 0.82 and the negative predictive value was 0.89, at the observed prevalence of 33.5%.

Conclusion

The sensitivity and specificity as evaluated by Bayesian statistic techniques differed from that previously reported. Properties of diagnostic tests may well vary between countries, laboratories and among populations of animals. In the absence of a true gold standard, the importance of validating new methods by appropriate statistical methods and with respect to the target population must be emphasized.     

Spatial and temporal investigations of reported movements,births and deaths of cattle and pigs in Sweden

Background

Livestock movements can affect the spread and control of contagious diseases and new data recording systems enable analysis of these movements. The results can be used for contingency planning, modelling of disease spread and design of disease control programs.

Methods

Data on the Swedish cattle and pig populations during the period July 2005 until June 2006 were obtained from databases held by the Swedish Board of Agriculture. Movements of cattle and pigs were investigated from geographical and temporal perspectives, births and deaths of cattle were investigated from a temporal perspective and the geographical distribution of holdings was also investigated.

Results

Most movements of cattle and pigs were to holdings within 100 km, but movements up to 1200 km occurred. Consequently, the majority of movements occurred within the same county or to adjacent counties. Approximately 54% of the cattle holdings and 45% of the pig holdings did not purchase any live animals. Seasonal variations in births and deaths of cattle were identified, with peaks in spring. Cattle movements peaked in spring and autumn. The maximum number of holdings within a 3 km radius of one holding was 45 for cattle and 23 for pigs, with large variations among counties. Missing data and reporting bias (digit preference) were detected in the data.

Conclusion

The databases are valuable tools in contact tracing. However since movements can be reported up to a week after the event and some data are missing they cannot replace other methods in the acute phase of an outbreak. We identified long distance transports of cattle and pigs, and these findings support an implementation of a total standstill in the country in the case of an outbreak of foot-and-mouth disease. The databases contain valuable information and improvements in data quality would make them even more useful.     

Geographical distribution of salmonella infected pig,cattle and sheep herds in Sweden 1993-2010

Background

The Swedish salmonella control programme covers the entire production chain, from feed to food. All salmonella serotypes are notifiable. On average, less than 20 cases of salmonella in food-producing animals are reported every year. In some situations, the cases would be expected to cluster geographically. The aim of this study was to illustrate the geographic distribution of the salmonella cases detected in pigs, cattle and sheep.

Methods

Data on all herds with pigs, cattle and sheep found to be infected with salmonella during the time period from 1993 to 2010 were obtained from the Swedish Board of Agriculture. Using the ArcGIS software, various maps were produced of infected herds, stratified on animal species as well as salmonella serotype. Based on ocular inspection of all maps, some were collapsed and some used separately. Data were also examined for temporal trends.

Results

No geographical clustering was observed for ovine or porcine cases. Cattle herds infected with Salmonella Dublin were mainly located in the southeast region and cattle herds infected with Salmonella Typhimurium in the most southern part of the country. Some seasonal variation was seen in cattle, but available data was not sufficient for further analyses.

Conclusions

Analyses of data on salmonella infected herds revealed some spatial and temporal patterns for salmonella in cattle. However, despite using 18 years'' of data, the number of infected herds was too low for any useful statistical analyses.     

Genetic basis of penicillin resistance of S. aureus isolated in bovine mastitis

Background

The blaZ gene encoding penicillin resistance can be located either chromosomally or on plasmids. The aim of this study was to investigate the genetic relationships and to determine the location of the blaZ gene in S. aureus isolated in bovine mastitis in Finland and Sweden.

Methods

Seventy-eight β-lactamase positive S. aureus isolates from bovine mastitis (34 from Finland and 44 from Sweden) were included in the study. The localization of blaZ gene was determined by Southern blotting. The blaZ genes of the isolates were sequenced and the sequences were translated to beta-lactamase proteins and further grouped as different protein signatures. The isolates and, as control, 33 Swedish and 36 Finnish beta-lactamase negative isolates were typed with pulsed-field gel electrophoresis (PFGE).

Results

In 26 out of 34 Finnish isolates (76.5%) and in 25 out of 44 Swedish isolates (56.8%) the blaZ gene was localized on a plasmid. Six different protein signatures were found. One signature was found only in four Swedish isolates, but all other signatures were found both in Finnish and Swedish isolates. The PFGE results revealed a diversity of S. aureus clones. The protein signatures were not clearly associated with certain pulsotypes.

Conclusions

The plasmid location of the blaZ gene was not statistically significantly more common in Finland than in Sweden, and hence does not explain the higher proportion of penicillin-resistant isolates of S. aureus causing bovine mastitis in Finland compared to Sweden.     

Efficacy of single dose of an inactivated porcine circovirus type 2 (PCV2) whole-virus vaccine with oil adjuvant in piglets

Background

Post-weaning multisystemic wasting syndrome (PMWS) associated with PCV2 is one of the most costly diseases currently faced by the swine industry. The development of effective vaccines against PCV2 infection has been accepted as an important strategy in the prophylaxis of PMWS.

Methods

In the present study, a PK-15 cell-adapted formalin-inactivated prototype vaccine candidate was prepared using a strain of PCV2 from China. Inactivation of the virus was accomplished using a standard formalin inactivation protocol. The protective properties of the inactivated PCV2 vaccine were evaluated in piglets. Ten 28-day-old pigs were randomly assigned to two groups, each with five. Group 1 was vaccinated intramuscularly with the inactivated virus preparation; Group 2 received sterile PBS as a placebo. By 28 days post-vaccination (DPV), Groups 1 and 2 were challenged intranasally and intramuscularly with 5 × 10⁷ TCID₅₀ of a virulent PCV2 isolate.

Results

The vaccinated pigs seroconverted to PCV2 and had high levels of serum antibodies to PCV2 at 28 days after vaccination, whereas the control pigs remained seronegative. No significant signs of clinical disease were recorded following the challenge with PCV2, but moderate amounts of PCV2 antigen were detected in most lymphoid organs of the control pigs. PCV2 was detected in two out of the five vaccinated pigs. Furthermore, pathological lesions and viremia were milder in the vaccinated group.

Conclusions

The obtained results indicate that the inactivated PCV2 virus vaccine with an oil adjuvant induce an immunological response in pigs that appears to provide protection from infection with PCV2. The vaccine, therefore, may have the potential to serve as a vaccine aimed to protect pigs from developing PMWS.     

Evidence of host adaptation in Lawsonia intracellularis infections

Background

Lawsonia intracellularis is the causative agent of proliferative enteropathy, an endemic disease in pigs and an emerging concern in horses. Enterocyte hyperplasia is a common lesion in every case but there are differences regarding clinical and pathological presentations among affected species. We hypothesize that host susceptibility to L. intracellularis infection depends on the species of origin of the bacterial isolate. The objective of this study was to evaluate the susceptibilities of pigs and horses to L. intracellularis infection using either a porcine or an equine isolate.

Materials and methods

Twelve foals and eighteen pigs were equally divided into three groups and infected with either a porcine or an equine isolate (10⁹L. Intracellularis/challenged animal), and a saline solution (negative control group). The animals were monitored regarding clinical signs, average of daily weight gain, fecal shedding of the bacteria by PCR and humoral serological response.

Results

Foals infected with the equine isolate developed moderate to severe clinical signs and maintained a lower average of weight gain compared to control foals. Fecal quantitative PCR in equine isolate-infected foals revealed higher amounts of bacterial DNA associated with longer duration of shedding compared with porcine isolate-infected foals. All four foals infected with the equine isolate demonstrated higher IgG titers in the serum compared with porcine isolate-infected foals. In the pig trial, diarrhea and seroconversion were only observed in animals infected with the porcine isolate. Pathological changes typical of proliferative enteropathy were observed in the necropsied foal infected with equine isolate and in the two necropsied pigs infected with the porcine isolate.

Conclusions

Evident clinical signs, longer periods of bacterial shedding and stronger serologic immune responses were observed in animals infected with species-specific isolates. These results show that host susceptibility is driven by the origin of the isolated L. intracellularis strain.     

Investigation of Chlamydophila spp. in dairy cows with reproductive disorders

Background

Reports worldwide indicate high prevalence of Chlamydophila spp. infection in cattle. To assess the prevalence in Sweden, 525 cows in 70 dairy herds with reproductive disorders was investigated.

Methods

To detect antibodies two commercially available kits were used. Moreover, 107 specimens, including vaginal swabs, organ tissues and milk were analysed by Polymerase Chain Reaction (PCR).

Results

Two (0.4%) cows were seropositive in the Pourquier Cp. abortus ELISA. The seroprevalence with the Chekit ELISA was 28% with no difference between cases and controls. Five specimens were positive in real-time PCR and further analysed by nested PCR. Cp. pecorum was confirmed by partial omp1 DNA sequencing of the nested PCR product of vaginal swabs from control cows.

Conclusion

The results suggest that Cp. abortus infection is absent or rare in Swedish cows whereas Cp. pecorum is probably more spread. They also suggest that Chlamydophila spp. are not related to reproduction disorders in Swedish cattle.     

Brain microabscesses in a porcine model of Staphylococcus aureus sepsis

Background

Sepsis caused by Staphylococcus aureus often leads to brain microabscesses in humans. Animal models of haematogenous brain abscesses would be useful to study this condition in detail. Recently, we developed a model of S. aureus sepsis in pigs and here we report that brain microabscesses develop in pigs with such induced S. aureus sepsis.Twelve pigs were divided into three groups. Nine pigs received an intravenous inoculation of S. aureus once at time 0 h (group 1) or twice at time 0 h and 12 h (groups 2 and 3). In each group the fourth pig served as control. The pigs were euthanized at time 12 h (Group 1), 24 h (Group 2) and 48 h (Group 3) after the first inoculation. The brains were collected and examined histopathologically.

Results

All inoculated pigs developed sepsis and seven out of nine pigs developed brain microabscesses. The microabscesses contained S. aureus and were located in the prosencephalon and mesencephalon. Chorioditis and meningitis occurred from 12 h after inoculation.

Conclusions

Pigs with experimental S. aureus sepsis often develop brain microabscesses. The porcine brain pathology mirrors the findings in human sepsis patients. We therefore suggest the pig as a useful animal model of the development of brain microabscesses caused by S. aureus sepsis.     

Risk factors for post-weaning diarrhoea on piglet producing farms in Finland

Background

Post-weaning diarrhoea (PWD) is a significant gastrointestinal disease in pigs. It is considered a multifactorial disease associated with proliferation of enterotoxigenic Escherichia coli in the intestinal tract of affected pigs. The aim of this study was to analyse risk factors related to the occurrence of PWD on Finnish piglet producing farms.

Methods

The data of a follow-up study of 73 conventional piglet producing farms was used in the case-control study. The selection of the 41 PWD case and 28 control farms was based on the use of antimicrobials for treating diarrhoea in weaned pigs and the answers related to the occurrence of diarrhoea after weaning in the questionnaire. Four intermediate farms were excluded from the statistical analysis.Altogether 39 factors related to herd characteristics, weaner pig management and pig health were studied. The median number of sows was 59.0 (IQR = 44.0; 74.5) and 52.5 (IQR = 36.8; 61.5) on the case and the control farms, respectively.The significances of the univariable associations between the explanatory variables and the outcome variable were tested, and in the multivariate analysis quasibinomial generalized linear models were applied.

Results

An increased risk of PWD was associated with the regimen of twice a day feeding and feed restriction after weaning (P = 0.02; compared to feeding three or more meals a day or the use of ad libitum feeding) and with a higher number of sows on the farm (P = 0.02; risk increasing with increasing number of sows). Automatic temperature control was associated with a decreased risk of PWD (P = 0.03; compared to manual temperature control).

Conclusion

Twice a day feeding of newly-weaned pigs should be avoided if the amount of feed given is restricted. Variation in ambient temperature should be minimized in housing of newly-weaned pigs and this can be achieved by using automatic temperature control. With increasing number of sows in the herds the risk of PWD increases and more attention should be paid to prevention of post-weaning diarrhoea.