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1.
Besides finishing pigs, sows are also believed to be important in the epidemiology of Salmonella. The study objective was to investigate the prevalence of Salmonella excretion in sows during an entire reproductive cycle. In 3 farrow-to-finish herds, groups of 34, 40 and 32 sows, respectively, were sampled serially. Faecal samples, environmental swabs and feed samples were taken and submitted to a qualitative Salmonella isolation. All isolates were characterised using RAPD and a representative number of isolates was serotyped. The prevalence of Salmonella excretion was < 10% during gestation, around farrowing and during lactation, but a significant increase in the number of Salmonella excreting sows was found in herds A (p < 0.01) and C (p = 0.02) after weaning. S. Infantis was the most prevalent serotype in herd A, S. Derby in herds B and C. Except for the S. Infantis group in herd A, all isolates within each group of the RAPD analysis belonged to the same serotype. Three sows in herd A and 1 sow in herd C shed different serotypes at different time points. The present results indicate that sows can maintain Salmonella infections in farrow-to-finish herds and that culled sows, leaving the herd after weaning, may constitute a substantial risk for contamination of their carcasses with Salmonella.  相似文献   

2.
A survey of the prevalence of Salmonella species infection was conducted on 59 Irish farrow-to-finish pig herds. Faecal samples were collected from the pens of first-stage weaners (growing pigs approximately three to 10 weeks of age), second-stage weaners (approximately 10 to 17 weeks of age) and fatteners, and from the dry sow and farrowing sow houses. The prevalence of infection was estimated to within 5 per cent with a 95 per cent confidence interval. Thirty of the 59 herds were infected, 12 with Salmonella Typhimurium only, eight with Salmonella Derby only and seven with both S Typhimurium and S Derby; serotypes London, Livingstone and Infantis were each isolated from a single herd. Farms in Ireland are assigned to one of three infection categories on the basis of the antibody levels in samples of meat juice taken at slaughter. When a herd was classified as either positive or negative on the basis of the isolation of Salmonella from at least one faecal sample there was no association between the herd's category as determined by meat juice serology and the probability of the isolation of Salmonella from the faecal samples. However, there were differences in prevalence between pigs at different stages of production in herds of different categories. Farrowing sow houses in moderately infected (category 2) herds had significantly lower infection rates (P < or = 0.05) than other herd categories and other stages of production. Pigs from first-stage weaner pens in slightly infected (category 1) herds were more likely to be infected with Salmonella than pigs at any other stage of production or category of herd.  相似文献   

3.
One hundred and seven fattening pig units randomly selected in Catalonia (Spain) were surveyed during 2001-2003, in order to determine the frequency of the prophylactic use of antimicrobials and mass treatments against respiratory and enteric disease outbreaks. Logistic regression and regression tree analysis were done to determine the factors associated with the on-farm mass antimicrobial usage. Fifty-eight per cent of the surveyed farms used mass antimicrobial prophylaxis; among them, 39% used two or more antimicrobials. The more frequently administered drugs were colistin, beta-lactams and tetracyclines. Fattening units from strict finishing farms were more likely to use antimicrobials than farrow-to-finish farms (Odds Ratio = 11.7) and farms with changing facilities were less likely to use these compounds (OR = 0.17). In the event of a respiratory disease outbreak, most farms applied mass treatment and 46% used two or more compounds, with tetracyclines, beta-lactams and sulphonamides being the most popular ones. Mass treatment with several compounds in case of respiratory problems was significantly related to the use of growth promoters on the farm (OR = 4.3). If an outbreak of an enteric disease occurred, most farms resorted also to a mass treatment and 48% used two or more drugs. The most frequent antimicrobial agent for the treatment of enteric disease was colistin. Fattening farms (OR = 6.9) and operations that perform routine antimicrobial prophylaxis (OR = 2.0) were more likely to use more than one antimicrobial agent for enteric diseases.  相似文献   

4.
Sera were collected from 6 large farrow-to-finish swine herds infected with pseudorabies virus (PRV) in Illinois. All herds were participating in the Large Herd Cleanup Study, a USDA-initiated project to evaluate the feasibility of eradicating pseudorabies from large farms (greater than 400 sows) by use of a combination of vaccination and management changes. Herd size ranged between 425 and 1,500 breeding females. Between April and July 1990, sera for measurement of PRV antibodies were obtained from 113 to 156 sows and 112 to 162 finishing pigs (body weight greater than 70 kg)/herd. Duplicate sera from 30 sows and 30 market-weight pigs/herd were obtained for measurement of serum antibodies to the following associated organisms: swine influenza virus, transmissible gastroenteritis virus, encephalomyocarditis virus, Actinobacillus pleuropneumoniae, Eperythrozoon suis, and 6 serovars of Leptospira interrogans. Prevalence of PRV antibodies attributable to field virus infection ranged between 53.8 and 100% for sows and between 0.7 and 97.3% for finishing pigs, as determined by the appropriate differential test for the vaccine being used on each farm. In only 1 herd, PRV seroprevalence was increased with higher sow parity. For associated infections, the risk of seropositivity attributable to PRV was not significant (for most infections) on all farms and varied among farms. Thus, pseudorabies did not appear, in general, to increase susceptibility to infection with other disease agents.  相似文献   

5.
Samples of serum from 76 gilts, 1440 sows, 1473 piglets and 3093 finishing pigs from 96 farrow-to-finish herds were tested for antibodies to encephalomyocarditis virus (EMCV) in microtitre serum neutralisation tests employing two strains of virus, one associated with myocarditis and the other with reproductive failure. The total seroprevalence of EMCV infection was 2.48 per cent. There was no significant difference between the seroprevalence of the reproductive failure strain (1.6 per cent) and the myocardial strain (1.85 per cent). The seroprevalence was higher in the gilts (6.57 per cent) and sows (5.13 per cent) than in the piglets (1 per cent) and finishing pigs (1.84 per cent), and the highest titres were observed in the sows (1:540) and finishing pigs (1:640). In the gilts, the difference in seroprevalence between the reproductive failure strain (3.95 per cent) and the myocardial strain (5.33 per cent) was wider than in the other groups.  相似文献   

6.
Suisynchron was applied to 2,258 gilts, including 850 from breeding farms. Forty-four pigs were checked to elucidate the influence of sexual maturity on the success of oestrus synchronisation. Suisynchron-Pr?mix was fed to the animals over 20 days, the daily dose for each pig having been 5 g. Twenty-four hours were allowed to elapse from the last administration before 1,500 I.U. PMSG were injected. Synchronised oestrus occurred in 81.2 per cent of all pigs between four and six days from serum injection.Fertilisation in response to first insemination was recorded from 72.9 percent of the pigs, their fertility rate being 9.7 piglets from each farrowing sow. The results of oestrus synchronisation obtained from fattening pigs were somewhat inferior to those recorded from pigs of breeding units. Suisynchron and serum of pregnant mares can synchronise oestrus in 91 per cent of all mateable sows with no previous cycle. The fertility rates recorded from such pigs did not exceed 59 per cent or were between 28.9 and 31.9 per cent lower than those recordable from pigs with a cycle history prior to the use of Suisynchron.  相似文献   

7.
Fifty randomly selected fattening pig herds were studied to investigate the epidemiological characteristics of infections with Actinobacillus pleuropneumoniae serovars 2, 3 and 9, and to identify risk factors for their within-herd seroprevalences. Information about 13 farm characteristics was obtained by means of a questionnaire and used to assess potential risk factors for the percentage of slaughter pigs with antibodies against each of the three serovars. The presence of antibodies was measured with an indirect ELISA. The median within-herd seroprevalence for serovar 2 was 58 per cent (range 0 to 100 per cent), for serovar 3, 53 per cent (range 10 to 95 per cent), and for serovar 9, 35 per cent (range 5 to 100 per cent). All but one farm tested positive for A pleuropneumoniae serovar 2, and all the farms were positive for A pleuropneumoniae serovars 3 and 9. There was a positive association (P < 0.05) between each pair of serovars. The within-herd seroprevalence of serovar 2 was significantly associated with the density of pig herds in the municipality (odds ratio [OR] = 1.60; P < 0.05) and with the absence of preventive medication at the start of the fattening period (OR = 2.77; P < 0.10). No significant risk factors were found for serovar 3. The percentage of pigs positive for serovar 9 was significantly associated with a slaughter date in June (OR = 2.30; P < 0.10) and with herds in which the finishing houses were not divided into separate compartments (OR = 2.99; P < 0.05).  相似文献   

8.
Mycoplasma suis (Eperythrozoon suis) was detected by PCR and Southern blot in 186 pigs (121 sows, 61 piglets and four boars) on four farms in southern Brazil. DNA was extracted from blood samples and a 16S rRNA gene fragment of M suis was amplified by PCR; Southern blot analysis was then performed on all the samples. Twenty-two of the sows (18.2 per cent) were positive by PCR, and 40 (33.1 per cent) were positive by Southern blot; only one piglet and one boar were positive. The packed cell volume and total plasma protein of the pigs and their PCR and Southern blot results were not significantly different on the four farms, but higher proportions of the pigs were positive by Southern blot than by PCR (P<0.05). The packed cell volume and total plasma protein concentrations of the M suis positive and negative sows were not significantly different.  相似文献   

9.
Five porcine finishing units, previously identified as contaminated by Salmonella, were sampled to identify possible sources of contamination and to study the distribution of Salmonella within the herds. A total of 208 environmental samples were taken and 87 samples (42%) were found contaminated by Salmonella spp. Salmonella was recovered from several types of samples. Among these, fecal material from pens, building environment such as doors, floors, ventilation units, dust and farm accessories were most often found positive. Some of the flies and rodents were also positive. Two of the finishing units were part of an integrated production system and the prevalence and distribution of Salmonella spp. at different production steps of the integrated facilities were studied. Forty-one farms were sampled and a total of 1923 faecal samples in randomly selected pens were analysed. One hundred and fifty-one samples (7.9%) were positive for Salmonella spp. Among the farms sampled, 70.7% (29/41) were positive for isolation of Salmonella. The different levels in the integrated production were unevenly contaminated. Replacement sow (15.9%) and finishing unit for gilts (21.9%) were the most contaminated levels. Ten serotypes of Salmonella (n = 132) were identified in the production pyramid with a predominance of Salmonella Derby (37.1%) and Salmonella Typhimurium (34.1%). Pulse Field Gel Electrophoresis analysis of the various isolates from serotypes and Salmonella Typhimurium, Salmonella Derby and Salmonella Anatum showed no variation in the genetic profiles, within each serotype, suggesting a vertical contamination throughout the different production steps.  相似文献   

10.
Porcine reproductive and respiratory syndrome (PRRS) is a disease of domestic swine characterized by exceptionally high clinical variability. This study addresses the question of whether clinical variability in PRRS results from (a) genetic variation among viral isolates and/or (b) variation in management practices among farms on which isolates are found. Genetic data (open reading frame 5 gene sequences) and data on farm characteristics and associated clinical disease signs were collected for 62 PRRS virus (PRRSV) field isolates, representing 52 farms. Clinical disease signs were interrelated — confirming that a true reproductive syndrome exists (involving abortions, infertility in sows, deaths of sows and preweaning mortality).

Pairs of farms experiencing deaths in their sow populations also tended to share viral isolates which were more similar to one another than expected by chance alone. This implies that sow death (one of the more-severe manifestations of PRRS) is under genetic influence. Large herd size was a significant risk factor for the death of sows and for respiratory disease in nursery pigs. All-in–all-out management practices in the nursery were protective against reproductive signs in the sow herd. All-in–all-out management practices in the finishing stages of production were protective against respiratory disease in nursery pigs — but were paradoxically associated with an increased risk of infertility in sows. These results suggest that farm-management practices can also influence which PRRS clinical signs are manifested during an outbreak. In general, signs associated with PRRS appear to result from a combination of genetic factors and herd-management characteristics. The relative contributions of these two influences differ depending on the specific clinical sign in question.  相似文献   


11.
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12.
A randomised, double-blinded, placebo-controlled study into the effectiveness and safety of a vaccine against porcine reproductive and respiratory syndrome virus (PRRSV) was carried out on three farms with a history compatible with chronic PRRSV infection; representative groups of sows and gilts were injected with a live vaccine against PRRSV, and during the next six weeks no side effects were observed. The remaining sows and gilts on the three farms were then vaccinated with the same vaccine. Again, no side effects were observed. There were significant reductions in abortion, reproductive disease, returns to oestrus and the numbers of stillborn pigs per sow, and significant increases in the numbers of liveborn pigs per sow and weaned pigs per sow among the vaccinated animals.  相似文献   

13.
A comparative serologic study was performed in seven single site (SS) farrow-to-finish farms and four multi-site (MS) farrow-to-finish farms, with or without post-weaning multisystemic wasting syndrome (PMWS). In each farm, 30 blood samples were collected for each category of the production cycle: sows, farrowing crate, nursery, grower pigs, and finishing pigs. Sera were evaluated for the presence of antibodies to porcine circovirus type-2 (PCV2) via immunoperoxidase monolayer assay. Serologic profiles for PCV2 were different between SS and MS farms. Seroconversion following the decline in maternal antibodies occurred at a later stage on SS farms (grower pigs) than MS farms (nursery pigs). MS farms tended to have lower antibody titers than SS farms in the categories of sow, piglet, and nursery, while higher antibody titers were found in grower pigs. Characterization of serologic profiles for different farms may provide important information for the adoption of vaccination programs.  相似文献   

14.
A cross-sectional survey was performed to estimate the prevalences of antibodies to Toxoplasma gondii (ELISA, IFAT), Sarcocystis spp. (ELISA, using S. miescheriana as antigen) and Neospora caninum (ELISA, immunoblotting) in sows from breeding farms in southern Hesse, Germany. A total of 2041 plasma samples of sows from 94 randomly selected farms was examined. Data on farm profiles, husbandry management and sows were collected by a questionnaire and exploratively analysed. For T. gondii the ELISA results agreed well with the results obtained by IFAT (kappa=0.71). Antibodies to T. gondii were detected by ELISA in 19% of the sows. Sixty-nine percent of the farms had at least one seropositive sow, and a within-farm seroprevalence of >or=50% was observed in 14% of all farms. The prevalence of anti-T. gondii antibodies was positively correlated with the age of sows. The within-herd seroprevalence was significantly higher in farms with reproductive disorders than in those without such problems. On the farm level, the farm type 'piglet production' (versus 'pedigree breeding' or 'farrow-to-finish') was the only risk factor associated with the presence of T. gondii-seropositive sows. Antibodies to Sarcocystis spp. were found in 29% of the sows. Seventy-two percent of the farms harboured at least one seropositive sow, and a within-farm seroprevalence of >or=50% was detected in 23% of all farms. The seroprevalence increased significantly with the age of sows. On the farm level, only the farm type 'piglet production' (versus 'pedigree breeding') and the replacement of sows by purchasing (versus raising on the own farm) were identified as risk factors for seropositivity. Antibodies to N. caninum were detected in one sow using both the screening ELISA and the confirmatory immunoblotting technique. This may indicate the first natural N. caninum infection in pigs.  相似文献   

15.
A comparative serologic study was performed in seven single site (SS) farrow-to-finish farms and four multi-site (MS) farrow-to-finish farms, with or without post-weaning multisystemic wasting syndrome (PMWS). In each farm, 30 blood samples were collected for each category of the production cycle: sows, farrowing crate, nursery, grower pigs, and finishing pigs. Sera were evaluated for the presence of antibodies to porcine circovirus type-2 (PCV2) via immunoperoxidase monolayer assay. Serologic profiles for PCV2 were different between SS and MS farms. Seroconversion following the decline in maternal antibodies occurred at a later stage on SS farms (grower pigs) than MS farms (nursery pigs). MS farms tended to have lower antibody titers than SS farms in the categories of sow, piglet, and nursery, while higher antibody titers were found in grower pigs. Characterization of serologic profiles for different farms may provide important information for the adoption of vaccination programs.  相似文献   

16.
The purposes of this study were to describe the clinical signs observed in PRRS positive herds during a porcine reproductive and respiratory syndrome (PRRS) outbreak in Ontario and to determine associations between these clinical signs and herd demographics and PRRS control strategies. All PRRS polymerase chain reaction-(PCR)-positive submissions to a diagnostic laboratory between September 1, 2004 and August 31, 2007 were identified (n = 1864). After meeting eligibility requirements and agreeing to voluntary study participation, producers from 455 of these submissions were surveyed for information on clinical signs observed in their herds, herd demographics, and PRRS control strategies used in their herds at the time that the PCR-positive samples were taken. Larger herd size was associated with an increased risk of reporting abortion, weakborn piglets, off-feed sows, and sow mortality in sow herds, and with an increased risk of reporting mortality in finishing herds. When disease control strategies were examined, use of a commercial PRRS vaccine in sows and gilts was associated with a decreased risk of reporting weakborn pigs and high pre-weaning mortality, while the use of serum inoculation in breeding animals was associated with an increased risk of reporting off-feed sows and sow mortality. Providing biofeedback of stillborn/mummified piglets, placenta or feces to gilts was associated with an increased risk of reporting respiratory disease and mortality in finishing pigs while all-in/all-out flow in farrowing rooms was associated with an increased risk of reporting sow mortality and weakborn piglets.  相似文献   

17.
Data were collected on the housing, management and disease factors in the weaning and finishing units of 49 integrated pig herds, 24 of them with a high incidence of arthritis at slaughter (case herds) and 25 with a low incidence (control herds). A median of 5.2 per cent (range 3.7 to 12.4 per cent) of the slaughtered pigs in the case herds had arthritis at meat inspection, compared with 2.2 per cent (range 0.3 to 2.8 per cent) in the control herds. In the farrowing units, high clinical sign scores for the lactating sows and piglets less than one week old and a low age at castration were associated with the case herds. In the weaning units, the herds with open partitions between the pens were 5.6 times more likely to be a case herd than the herds with solid walls. A higher age at weaning and moving the piglets at weaning from the farrowing pen instead of the sows decreased the likelihood of being a case herd. In the finishing units, a higher score for clinical signs, using a proper hospital pen, disinfecting the pens between the groups and using a feeding plan increased the likelihood of being a case herd. In total, 145 condemned joints, a median of four (up to six per herd), were collected at the slaughterhouse. In the case herds, 71 of 76 joints (93.4 per cent) had lesions related to osteochondrosis and in the control herds 66 of 69 joints (95.6 per cent) had such lesions. Only two of 11 joints from the case herds and one of 12 joints from the control herds that were examined bacteriologically were positive for Stapylococcus aureus and/or Streptococcus species.  相似文献   

18.
Necrotising enteritis had been the cause of death of 4.9 per cent in 5,177 nursed piglets, which was established by pathological examination. The number of piglets, in that context, which had come from industrialised sow breeding units was equivalent to 92 per cent. The nursed piglet held the third position, next to smaller ruminants (19.4 per cent) and fowl (6.0 per cent), with regard to the occurrence of Clostridium perfringens enterotoxemia or necrotising enteritis in 112,218 animals which were pathologically examined after death. Necrotising enteritis so far has been rare in the GDR. No regional accumulation has been observed. Several outbreaks on industrialised sow breeding units actually remained stationary. The occurrence of the disease may be favoured by a number of factors which are conducive to accumulation of Clostridium perfringens Type C in a given stock. Group keeping of pregnant sows, simultaneous farrowing of larger groups of sows, group treatment of nursed piglets, using neomycin, chloramphenicol, oxytetracycline, and other antibiotics to which Clostridium perfringens is primarily resistant or has acquired resistance in the course of time are some of those contributive factors. Transmission of Clostridium perfringens Type C through feedstuff is possible, though it would lead to a real outbreak only by high intensity of the contamination, and it played a minor role in proliferation of the disease. 3479 Clostridium perfringens strains were isolated from 9,481 animals, both clinically intact and after death, with 30 species being included. Type classification revealed 2454 strains of Type A (70 per cent), 204 of Type D (5.88 per cent), 164 of Type C (four per cent), and 48 of Type B (1.34 per cent). There were 688 atoxic strains (17 per cent). Swine is the major carrier of Clostridium perfringens Type C, with 87 per cent of all Clostridium perfringens Type C strains having been isolated from swine. Swine was followed by fowl (four per cent), sheep (four per cent), cattle, rabbit, and dog (1.27 per cent each). Clostridium perfringens Type C was obtained from the faeces of clinically intact sows in seven instances, including two cases with sows (0.46 per cent) from farms with no previous record of necrotising enteritis.  相似文献   

19.
The aim of this study was to determine the farm prevalence of Salmonella in 90 Alberta finishing swine farms over a 5-month period, to evaluate Salmonella distribution in the farm environment and to describe Salmonella serovar diversity on these farms. Ten veterinary practitioners selected 90 Alberta swine farms based on an annual production of > or =2000 market pigs per farm and the willingness of the producers to participate in the study. Between May and September 2000, twenty samples were collected from finishing swine and the environment of each farm. The annual production of selected farms represented approximately 25% of the market swine production in Alberta. Participating farms were geographically representative of major swine production areas in Alberta. Sixty (66.7%) farms had at least one Salmonella-positive sample, with confidence interval (CI) of 57.1-77.2%. Salmonella were detected in 14.3% of fecal and 20.1% of environmental samples. The number of Salmonella-positive samples per farm ranged from 1 to 19. Among environmental samples, Salmonella were most frequently recovered from boots (38.6%) and the main drain (31.8%). Twenty-two serovars were detected on the 60 Salmonella-positive farms. Serovars Typhimurium (78 isolates), Derby (71 isolates) and Infantis (47 isolates) were the most common. A single serovar was detected on 58 farms, while 2, 3 and >3 serovars were detected on 15, 10 and 7 farms, respectively. The Salmonella farm status changed frequently over the 5-month period indicating the dynamic nature of Salmonella infections on these farms.  相似文献   

20.
To set productivity standards and targets, and investigate inter-relationships between key measurements in swine breeding herds, farm productivity measurements were analyzed on 87 Japanese commercial farms in 14 prefectures. The 87 herds were ranked on the basis of number of pigs weaned per mated female per year (PWMFY), and 23 herds in the upper 25th percentile of this ranking were designated as high-performing farms. Productivity measurements on the high-performing farms were compared with values for the remaining farms. The high-performing farms had shorter farrowing intervals, greater litters per mated female per year (LMFY), greater pigs weaned per sow (PWS), and greater mean parity of culled sows than the remaining farms (P<0.01). No difference in lactation duration was found between the two groups (P>0.10). For both farm groups, correlations of key reproductive measurements were determined. Lactation duration was not correlated with LMFY, PWS and PWMFY on the high-performing farms, while short lactation duration was correlated with greater LMFY and PWMFY on the remaining farms (P<0.01). In contrast to lactation duration, farrowing interval was correlated with PWS on the high-performing farms, but not on the remaining farms. Mean parity of culled sows were correlated to PWS and pigs born alive per sow on the high performing farms, but not with any measurements on the remaining farms. These results suggest that high-performing farms have used different herd management from the remaining farms.  相似文献   

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