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1.
To determine the persistence period of C-strain vaccine virus in immunized animals, domestic pigs and wild boars were vaccinated orally and killed on different days post vaccinationem (dpv). Tissue samples were taken at necropsy from both species for detection of C-strain virus. From domestic pigs nasal swabs and faeces were also collected. During the investigation period (2-12 dpv) vaccine virus could never be detected in nasal secretions and in faeces of vaccinated domestic pigs. In contrast, C-strain virus was found in organs until day 8 pv in domestic pigs and until day 9 pv in wild boars. Whereas in domestic pigs virus was detected in tonsils, Ln. mandibularis or in spleen, in wild boar it only was found in tonsils. We conclude that C-strain vaccine virus is not detectable in wild boars longer than 10-12 days after intake of the vaccine baits.  相似文献   

2.
Salmonellosis was the diagnosis in 63 of 327 consecutive porcine necropsy accessions during a one year period in Indiana, an incidence four to ten times that previously reported in other areas. A herd outbreak was usually either a septicemic disease characterized by sudden mortality. Little overlap between these two syndromes were seen. Animals dying with the septicemic form usually yielded Salmonella choleraesuis var. kunzendorf on culture. Salmonella typhimurium was the usual isolate from cases of enteric salmonellosis. Oral inoculation of SPF pigs with S. typhimurium resulted in a disease similar to naturally occurring enteric salmonellosis. The pathology of porcine salmonellosis due to S. typhimurium is described.  相似文献   

3.
To determine the persistence period of C‐strain vaccine virus in immunized animals, domestic pigs and wild boars were vaccinated orally and killed on different days post vaccinationem (dpv). Tissue samples were taken at necropsy from both species for detection of C‐strain virus. From domestic pigs nasal swabs and faeces were also collected. During the investigation period (2–12 dpv) vaccine virus could never be detected in nasal secretions and in faeces of vaccinated domestic pigs. In contrast, C‐strain virus was found in organs until day 8 pv in domestic pigs and until day 9 pv in wild boars. Whereas in domestic pigs virus was detected in tonsils, Ln. mandibularis or in spleen, in wild boar it only was found in tonsils. We conclude that C‐strain vaccine virus is not detectable in wild boars longer than 10–12 days after intake of the vaccine baits.  相似文献   

4.
The effect of control programmes on proliferative enteropathy and its causative agent (Lawsonia intracellularis) was investigated on four farrow-to-finish pig farms in Britain. Faeces samples from groups of boars and gilts in breeding programmes, and from preweaning and postweaning pigs were monitored prospectively every month for six months by a L intracellularis-specific polymerase chain reaction (PCR). On one farm with 150 sows, an outbreak of acute proliferative enteropathy in boars and gilts was controlled clinically by the use of tiamulin and chlortetracycline. The percentage of detectable PCR-positive pigs decreased from between 50 to 70 per cent to zero in the treated pigs and their progeny less than 14 weeks old, but clinical signs of the disease and PCR-positive pigs were detected in some 14-week-old pigs derived from the treated groups. On another farm with 160 sows, an outbreak of chronic proliferative enteropathy in six-week-old pigs (23 to 26 per cent PCR-positive) was controlled by the use of oral tylosin phosphate. Faeces samples from the medicated pigs on this farm remained PCR-negative during the study period, whereas samples from unmedicated control pigs showed that the infection persisted in some pigs for at least six weeks. The two other monitored farms remained PCR-negative and clinically negative for the disease during the study period. These farms treated the pigs regularly with oral chlortetracycline.  相似文献   

5.
Trichinellosis is a foodborne disease caused by the consumption of raw meat and raw meat-derived products from swine, horse and some game animals infected with nematode worms of the genus Trichinella. Between June 2006 and February 2011, 16 million domestic pigs and 0.22 million wild boars (Sus scrofa) were tested for Trichinella sp. in Hungary. Trichinella infection was not found in any pigs slaughtered for public consumption. Nevertheless, Trichinella spiralis was detected in four backyard pigs when trace back was done following a family outbreak. Trichinella infection was demonstrated in 17 wild boars (0.0077%). Larvae from wild boars were identified as Trichinella britovi (64.7%), T. spiralis (29.4%) and Trichinella pseudospiralis (5.9%). Although the prevalence of Trichinella sp. infection in wild boars and domestic pigs is very low, the spatial analysis reveals that the level of risk differs by region in Hungary. Most of the T. britovi infected wild boars (63.6%) were shot in the north-eastern mountain area of Hungary; whereas domestic pigs and wild boars infected with T. spiralis were detected only in the southern counties bordering Croatia and Romania. In the north-western and central counties, the prevalence of Trichinella infection seems to be negligible.  相似文献   

6.
One hundred thirty Yorkshire-Landrace (YL), Chester White-Landrace (CL) and Chester White-Yorkshire (CY) F1 crossbred sows were mated randomly to Duroc (D), Hampshire (H), Farmers Hybrid 414 (FH414) or Farmers Hybrid 929 (FH929) boars. These matings produced 321 litters and 3,379 pigs, which were used to determine the effect of sire breeding and dam breeding on preweaning and postweaning performance of the pigs and litters. Litter size born alive, litter size at 56 d, litter weight at 56 d and litter weight per day of age to 100 kg were lower in litters sired by H boars than in those sired by D boars. However, sizes and weights of litters sired by D and H boars were not different from those sired by FH414 and FH929 boars. Litter sizes at birth were larger for litters out of CL and CY sows than those out of YL sows, but significant differences were not found for litter sizes at 21 d, 56 d or at marketing. Pigs sired by H boars were heavier at birth than pigs sired by D boars. Pigs sired by H boars did not differ significantly in weights at 21 and 56 d or in postweaning daily gains or days to 100 kg from pigs sired by D boars. Pigs out of CL dams were heavier at birth, 21 d and 56 d of age than pigs out of CY dams, but did not differ significantly in postweaning gains or in days to 100 kg. Pigs sired by D and H boars had less ultrasonic fat than pigs sired by FH414 and FH929 boars. Pigs sired by FH929 boars were leaner than pigs sired by FH414 boars.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

7.
Brucella suis biovar 2 is the most common aetiological agent of porcine brucellosis in Europe. B. suis biovar 2 is considered to have low zoonotic potential, but is a causative agent of reproductive losses in pigs, and it is thus economically important. The multilocus variable-number of tandem repeats genotyping analysis of 16 loci (MLVA-16) has proven to be highly discriminatory and is the most suitable assay for simultaneously identifying B. suis and tracking infections. The aim of this study was to investigate the relatedness between isolates of B. suis biovar 2 obtained during a brucellosis outbreak in domestic pigs and isolates from wild boars and hares collected from proximal or remote geographical areas by MLVA-16. A cluster analysis of the MLVA-16 data revealed that most of the isolates obtained from Switzerland clustered together, with the exception of one isolate. The outbreak isolates constituted a unique subcluster (with a genetic similarity >93.8%) distinct from that of the isolates obtained from wild animals, suggesting that direct transmission of the bacterium from wild boars to domestic pigs did not occur in this outbreak. To obtain a representative number of isolates for MLVA-16, alternative methods of Brucella spp. isolation from tissue samples were compared with conventional direct cultivation on a Brucella-selective agar. We observed an enhanced sensitivity when mechanical homogenisation was followed by host cell lysis prior to cultivation on the Brucella-selective agar. This work demonstrates that MLVA-16 is an excellent tool for both monitoring brucellosis and investigating outbreaks. Additionally, we present efficient alternatives for the isolation of Brucella spp.  相似文献   

8.
Coronavirus-like particles were visualized by electron microscopy in the intestinal contents of piglets during a diarrheal outbreak on a Quebec pig farm. The precipitating antigens of transmissible gastroenteritis virus were not detected in the intestinal contents of diarrheic animals by counter-immunoelectrophoresis. Insignificant antibody titers against transmissible gastroenteritis virus were demonstrated in the sera of convalescent pigs by indirect immunofluorescence and these sera did not react with transmissible gastroenteritis virus when tested by immunoelectron microscopy. The causative agent could not be isolated in cell cultures. It was concluded that a coronavirus antigenically distinct from transmissible gastroenteritis virus was responsible for the enteric problems observed on this farm. The outbreak was controlled after oral inoculation of adult pigs with infected intestinal contents.  相似文献   

9.
This report describes an outbreak of coccidiosis in a boar stud. A live, untreated, adult boar with a history of diarrhea was submitted to the Iowa State University Veterinary Diagnostic Laboratory, Ames, IA. For a 3-month period, approximately 40% of the boars in this stud had developed gray to brown diarrhea that lasted 1-3 days. Affected boars did not lose condition, and antibiotic therapy did not appear to affect the clinical course ofthe disease. At necropsy, the distal ileum was palpably thickened and covered by a thick, yellow-green, fibrinous exudate. Microscopic changes in the ileum consisted of an erosive enteritis associated with the presence of numerous coccidia within mid to superficial villus enterocytes. The mucosa was covered by a fibrinous exudate admixed with numerous nonsporulated coccidian oocysts. A light growth of Salmonella enterica serovar Derby was isolated from the small intestine of this animal, but laboratory tests were negative for Lawsonia and Brachyspira spp. Individual or paired fecal samples were obtained from 6 additional boars experiencing similar clinical signs. Numerous Eimeria spinosa oocysts were identified in these samples. Neither Salmonella nor Brachyspira spp. were cultured from submitted fecal samples. Necropsy of a live boar and examination of feces from 6 additional animals confirmed that the mild, sporadic, transient diarrhea in this boar stud was due to coccidiosis.  相似文献   

10.
A corticosteroid treatment regimen, together with peripheral blood lymphocyte transformation and virus isolation, were used as epizootiologic tools to study pigs seropositive to pseudorabies (PR) virus, but of unknown PR viral infection status. After treatment with 160 mg of dexamethasone daily for 5 days, PR virus was isolated from 2 of 3 adult littermate boars that carried antibodies to PR virus. These pigs also transferred infection to a specific-pathogen-free sentinel penmate . After dexamethasone treatment, increased lymphocyte stimulation indices were detected in all PR virus seropositive pigs. Pseudorabies virus was not isolated from a seronegative littermate gilt of the seropositive boars. The gilt also remained PR virus seronegative and negative for lymphocyte transformation. Before dexamethasone treatment, the 3 boars and 1 gilt were seronegative to the PR viral serum neutralization (SN) test at 11 weeks of age. At 13 weeks of age while still SN negative, these pigs were moved to a building and randomly penned with 76 other SN-negative pigs. At 18 weeks of age, all pigs in the building were PR virus seronegative, but at 25 weeks of age, the 3 boars were seropositive and the gilt was seronegative. There were no other pigs in the building that had antibodies to PR virus before the addition or after the removal of these pigs. Seemingly, the 3 boars were infected with PR virus before 13 weeks of age indicating that PR virus infection of swine may occur in the absence of detectable SN antibodies.  相似文献   

11.
In this study, the performance of male pigs immunized against GnRH was determined in relation to the onset of their biological response to the immunization. Pigs were immunized at 9 and 17 wk of age and were housed in a pen together with both a surgically castrated and an intact boar littermate. Feed intake was restricted to 2.8 to 3.2 times maintenance requirement for energy. Animals were weighed weekly and slaughtered at 108 kg BW. Depending on the time of onset of the response after immunization in terms of biological effects, immunized pigs were retrospectively grouped into two categories. One category consisted of the immunized pigs, which had undetectable or low levels of LH and testosterone at the time of booster immunization-known as "early" responding immunocastrates (E-IM, n = 8), whereas the "late" responding immunocastrates (L-IM, n = 7) had substantial LH and testosterone levels at that time. This dichotomy of the response to immunization also was reflected in testis weight, with 17 g and 40 g for E-IM and L-IM pigs, respectively. At slaughter, testis size and weight were reduced (P < 0.001) in the immunocastrated pigs as compared to the intact boars. Androstenone concentrations in backfat of all immunocastrated pigs were undetectable. Growth performance (i.e., ADG and feed efficiency [FE, g gain/kg feed]), was better in boars and L-IM pigs than in surgical castrates and E-IM pigs (P < 0.05). Average daily gain and FE did not differ between E-IM pigs and the surgical castrates, but intact boars performed better than L-IM (P < 0.02). There were no significant differences in carcass quality (backfat thickness and meat percentage) between boars and surgical castrates at slaughter. However, for both characteristics L-IM pigs and intact boars performed better (P < 0.03) than E-IM pigs. Thus, growth performance in L-IM is better than in either E-IM or surgical castrates.  相似文献   

12.
Thirty-seven pigs with an initial live weight of 60 kg were used to investigate the effects of daily exogenous porcine somatotropin (pST) administration at two dose levels (0 and 100 micrograms.kg-1.d-1) for a 31-d period on muscle fiber characteristics and meat tenderness of boars, gilts and barrows. Excipient boars and gilts had more alpha W and fewer alpha R fibers than did those receiving pST. The percentage of muscle fiber type for barrows was not affected by pST treatment. The administration of pST resulted in an increase in muscle fiber size for all three fiber types in all three sexes, but these changes were of greater magnitude in barrows (31.8%) and gilts (27.8%) than in boars (9.3%). Somatotropin negated the intrinsic sex effect differences in fiber area of the pigs. There was no difference in tenderness among excipient boars, barrows and gilts; however, with the inclusion of pST, shear force decreased in boars and gilts and increased in barrows. A high proportion of the pST-treated pigs contained giant fibers in the longissimus muscle. Furthermore, a small proportion of the pST-treated pigs exhibited pale, soft, exudative muscle. Whether the giant fiber anomalies occurred through increased muscle activity or from fibers undergoing degenerative changes was not determined.  相似文献   

13.
The aim of the present study was to survey the prevalences of the enteric pathogens Brachyspira hyodysenteriae, Brachyspira pilosicoli and Lawsonia intracellularis in Swedish growing pigs and in the Swedish wild boar population and to relate these findings to clinical signs. The study included 105 randomly selected herds, constituting approximately one third of Swedish herds with a herd size of >100 sows. The herds were located all over the country. In these herds, growth promoters were not used and pigs sampled were not subjected to any medication. From each herd, samples were taken from 10 growing pigs aged 8-12 weeks, corresponding to approximately 2.5% of all growing pigs present in the herd at the sampling occasion. If possible, the samples were taken from pigs with diarrhoea. Forty-eight faecal samples and 71 rectal swabs were also taken from free-living wild boars (31 piglets, 19 growers and 21 adult animals) at shooting. The samples were analysed by culture and biochemical tests for the presence of Brachyspira spp. and by nested PCR for the presence of L. intracellularis. Brachyspira hyodysenteriae was not demonstrated in any sample. Brachyspira intermedia was detected in 22 samples originating from 15 herds, Brachyspira innocens/Brachyspira murdochii was detected in 370 samples from 82 herds and B. pilosicoli was detected in 134 samples originating from 34 herds. In 21 herds and in 534 samples, no Brachyspira spp. were detected. Lawsonia intracellularis was demonstrated in 285 samples from 50 herds. Further, 418 samples from conventional herds were negative with respect to L. intracellularis and in 345 samples the PCR had been inhibited. All samples from the wild boars were negative for Brachyspira spp., 12 of 48 samples were negative for L. intracellularis, and in 36 wild boar samples, the PCR was inhibited.  相似文献   

14.
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15.
Peri- and postpubertal boars accumulate substances (e.g., androstenone and skatole) in their fatty tissue that are responsible for boar taint in pork. The objective of this study was to assess the efficacy of a GnRH vaccine, Improvac, in eliminating boar taint. Three hundred male (200 intact boars, 100 barrows) crossbred (Large White x Landrace) pigs were used in a 2 x 3 factorially arranged experiment. The respective factors were sex group (barrows, boars treated with placebo, or boars treated with Improvac) and slaughter age (23 or 26 wk). Vaccines were administered 8 and 4 wk before slaughter. All Improvac-treated pigs exhibited anti-GnRH titers. Testes and bulbo-urethral gland weights in treated pigs were reduced by approximately 50% (P < 0.001) and serum testosterone levels were below 2 ng/mL in the majority of treated boars (94 and 92% across both age groups at 2 and 4 wk, respectively). Boar taint, as assessed by the concentration of androstenone and skatole in s.c. fat, was suppressed to low or undetectable levels in 100% of Improvac-treated boars. No Improvac-treated pigs had significant concentrations of either androstenone (> 1.0 microg/g) or skatole (> 0.20 microg/g). In contrast, 49.5% of placebo-treated controls had significant androstenone and 10.8% had significant skatole levels, resulting in 10% of the control boars with high concentrations of both compounds. The mean concentrations of taint compounds in the Improvac-treated pigs were not significantly different from those in barrows. Improvac-treated boars grew more rapidly (P = 0.051 and < 0.001 for pigs slaughtered at 23 and 26 wk of age, respectively) than control boars over the 4 wk after the secondary vaccination, possibly because of reduced sexual and aggressive activities. Compared with barrows, Improvac-treated boars were leaner and had superior feed conversion efficiency. The vaccine was well tolerated by the pigs, and no observable site reactions could be detected at the time of slaughter. Vaccination of boars with Improvac allows production of heavy boars with improved meat quality through prevention and control of boar taint.  相似文献   

16.
In experiments with young fattening boars, implanted at 50 kg with either oestradiol 17 beta (34 mg) (O group) or oestradiol 17 beta + testosterone (20 + 200 mg) (TO group) and fed the same amount of a protein rich diet, there was not any favourable effect on growth rate, feed conversion efficiency, carcass composition and protein retention, as calculated by carcass analysis of slaughter weight pigs and 50 kg live weight pigs. There were no differences in serum steroid concentrations between control and implanted boars, but there were differences in macroscopic and histological aspects of the gonads, which were significant between control and TO groups. These results were confirmed by the suppression in both treated groups of the androstenone concentration in backfat samples, steroid which is responsible for the sexual odour of the meat of boars.  相似文献   

17.
An outbreak of proliferative haemorrhagic enteropathy (PHE) occurred in two epidodes and affected 372 adult pigs in the breeding units of a minimal disease piggery; 186 pigs died. In the initial episode breeding sows and boars of all ages were affected, suggesting infection of a fully susceptible population. Animals involved in the first episode of the disease did not show clinical symptoms at a later date and further clinical cases occurred only in animals introduced into the breeding population. Antibiotic feed medication was an effective method of prophylaxis. Bacteria resembling Campylobacter sputorum subspecies mucosalis were isolated from the intestinal mucosa of affected animals.  相似文献   

18.
Enterotoxigenic Bacteroides fragilis (ETBF) was isolated from intestinal contents of 10 of 45 pigs with diarrhea. Of 10 ETBF-positive pigs, seven were 1 to 4 weeks of age, whereas three pigs had diarrhea after weaning (6 to 8 weeks of age). Of ten pigs infected with ETBF, nine were also infected with K88-positive Escherichia coli, rotavirus, coronavirus, coccidia, or Cryptosporidium. Of 11 conventional pigs exposed to ETBF at 1 to 2 days of age, two subsequently developed fatal postweaning diarrhea. An ETBF isolate, serologically similar to the challenge-exposure strain, was isolated from the feces of the two diarrheal pigs, but not from three healthy littermates. Fatal enteric disease occurred in 11 of 12 adult rabbits with ligated ceca after approximately 5 X 10(9) colony-forming units of ETBF were injected into the ileum. Disease in rabbits was characterized by anorexia and severe, mucoid, hemorrhagic diarrhea. Of 11 rabbits given non-ETBF or sterile brain-heart infusion broth, ten remained clinically normal during the 7-day observation period.  相似文献   

19.
Ten thousand one hundred sixty-nine pigs were farrowed in 844 litters that were produced by mating Duroc (D), Yorkshire (Y) and Hampshire (H) boars to Duroc-Landrace (DL), Yorkshire-Landrace (YL) and Hampshire-Landrace (HL) sows to study the effect of sire breed, dam breeding and gestation environment (pasture lots vs confinement stalls) on pig weights, survival rates and feed efficiency. Pigs sired by H boars were .05 kg heavier at birth than Y-sired pigs and .2 kg heavier at 21 d than Y- and D-sired pigs, but they were .6 kg smaller at 56 d. D-sired pigs grew .028 kg/d faster from 56 d to 100 kg and reached 100 kg approximately 5 d sooner than the Y- and the H-sired pigs. At birth, pigs out of DL sows were .21 kg heavier than pigs out of YL sows. Pigs out of HL sows grew .025 and .021 kg/d slower from 56 d to 100 kg compared with pigs out of DL and YL sows, respectively. Sows in the pasture gestation system produced pigs that were .05 kg heavier at birth than pigs out of sows in gestation stalls. Three-breed-cross pigs were .9 kg heavier at 56 d, grew .039 kg/d faster and took 7.9 fewer days to reach 100 kg than backcross pigs. The H sire breed had lower survival rates of pigs at 21 d and to 100 kg of those born alive (P less than .10), compared with pigs sired by D and Y boars. Pigs out of HL dams had the highest survival rates, whereas pigs out of YL sows had the lowest survival rates at birth, 21 d and at 100 kg. Three-breed-cross pigs averaged .025, .028 and .035 greater survival rates at birth, 21 d and 56 d than backcross pigs. Feed efficiency was most desirable in pens of pigs sired by H and D boars compared with pens of pigs sired by Y boars. However, pens of pigs with YL dams were more efficient than pens of pigs with HL dams.  相似文献   

20.
A 2-yr study compared progeny performance of high (HI) and low (LI) indexing central test station boars purchased in Iowa, Missouri, Nebraska and Oklahoma. Boars were evaluated for a National Swine Improvement Federation index recommended for central test stations. The 1st yr 22 Hampshire boars were mated to three- and four-breed Duroc, Yorkshire, Landrace and Spotted cross gilts. A disease outbreak the first farrowing season caused severe death loss and reduced performance. From 198 litters, 826 pigs completed their gain test. The 2nd yr 23 Duroc boars were mated randomly to gilts produced the previous year. From 181 litters, 1,070 pigs completed their gain test. No differences existed for postweaning average daily gain (ADG) and probe backfat thickness (PBF); however, progeny sired by HI Hampshire boars were an average of 5.66 units better for the index (I) compared with progeny of LI Hampshire boars. Gilt progeny of HI Duroc boars were .03 kg, .79 mm and 3.93 units greater for ADG, PBF and I, respectively, than LI Duroc-sired gilts. Barrow progeny of LI Duroc boars gained .01 kg/d faster, had .59 mm more PBF and were no different for I than barrows sired by HI Duroc boars. Maternal grandsire effects were important for Duroc-sired pigs, with gilts of HI maternal grandsires having .01 kg faster ADG, yet barrows of HI maternal grandsires had .02 kg slower ADG as compared with gilts and barrows having LI maternal grandsires, respectively.  相似文献   

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