ISSN:0165-2176    

DOI:10.1080/01652176.2000.9695038

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

In early 1991, the Dutch pig industry was struck by the so‐called mystery swine disease. Large‐scale laboratory investigations were undertaken to search for the aetiological agent. We focused on isolating viruses and mycoplasmas, and we tested paired sera of affected sows for antibodies against ten known pig viruses. The mycoplasmasM. hysonoviae,M. hyopneumoniae, andAcheloplasma laidlawii, and the viruses encephalomyocarditis virus and porcine enterovirus types 2 and 7 were isolated from individual pigs. An unknown agent however, was isolated from 16 of 20 piglets and from 41 of 63 sows. This agent was characterized as a virus and designated Lelystad virus. No relationship between this virus and other viruses has yet been established. Of 165 sows reportedly affected by the disease, 123 (75 per cent) seroconverted to Lelystad virus, whereas less than 10 per cent seroconverted to any of the other virus isolates or to known viral pathogens. Antibodies directed against Lelystad virus were also found in pigs with mystery swine disease in England, Germany, and the United States. We conclude that infection with Lelystad virus is the likely cause of mystery swine disease.

ISSN:0165-2176    

DOI:10.1080/01652176.2000.9695039

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Brucellosis, caused by bacteria of the genusBrucella, is a contagious disease that causes economic loss to owners of domestic animals due to loss of progeny and milk yield. Because cattle, sheep, goats, and to a lesser extent pigs are considered to be the source of human brucellosis, serological tests have been used to screen domestic animals for antibodies againstBrucella. Although the serological tests helped to eradicate brucellosis in many countries, serological tests are not always adequate to detect latent carriers ofBrucella. Therefore, the use of the skin delayed‐type hypersensitivity (SDTH) test, which is independent of circulating antibodies, might improve the diagnosis of brucellosis. In the literature, however, there are conflicting reports as to the value of the SDTH test for the diagnosis of brucellosis. Some studies consider the test unreliable, whereas others advocate its use because it detects brucellosis earlier than serological tests. The objectives of this study were therefore to assess the characteristics of the SDTH test, to select aBrucellastrain that will yield a suitable brucellin for use in the field, and to determine whether the use of serological tests in combination with the SDTH test improves the detection of brucellosis. The results of this study clearly show that the SDTH test detects latent carriers ofBrucellaand confirms brucellosis in cattle with ambiguous serological test results. Brucellins prepared from smooth or mucoid strains ofBrucellaare better suited for use in the field than brucellins prepared from rough strains because they detect brucellosis in cattle with acute as well as chronic infection. The SDTH test is highly specific (99.3% specificity), and repeated testing of naive cattle or cattle infected with microorganisms that serologically cross‐react withBrucelladoes not sensitize cattle to subsequent SDTH tests. However, it is possible that some naive cattle may serologically react to the injection of brucellin. The effect of these serological reactions on the sero‐diagnosis of brucellosis is limited, because cattle may only now and then react serologically either with the serum agglutination test (SAT) or the complement fixation test (CFT). Nevertheless, cattle infected with microorganisms that serologically cross‐react withBrucellamay test seropositive for brucellosis 4 to 7 weeks after injection of brucellin, depending on the cross‐reacting microorganism. The value of the SDTH test for the diagnosis of brucellosis was demonstrated after an outbreak of brucellosis. When the SDTH test was used in combination with SAT and CFT at diagnostic threshold ≥2 mm or ≥1 mm (increase in skinfold thickness), respectively, 39/44 (88%) or 42/44 (95%) of the infected cattle were detected compared with only 27/44 (61%) when SAT and CFT were used. When cattle in areas of low prevalence or in areas free from brucellosis are tested with the SDTH test an increase ≥2 mm in skinfold thickness should be considered indicative of infection. When the control and eradication of brucellosis is based on test‐and‐slaughter, an increase of ≥1 mm in skinfold thickness should be considered indicative of infection. Repeated serological testing complemented with the SDTH test in this programme will shorten the quarantine (movement control) period of a suspect herd, limiting the financial loss incurred during outbreaks of the disease. Consequently, since the SDTH test usually does not interfere with the serological diagnosis and can safely be used to establish the infection status of cattle in a suspect herd, it is opportune to consider adding the SDTH test to the procedure currently used to diagnose brucellosis in individual animals.

ISSN:0165-2176    

DOI:10.1080/01652176.2000.9695040

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

In a controlled and randomized field trial carried out in three European countries, 219 fattening pigs, from seven farms with respiratory disease problems, were treated intramuscularly for three or five days either with marbofloxacin 2 mg/kg/day, or with amoxicillin 7 mg/kg/day. Pigs were monitored daily until D5 (Day 5) and again at D21, and were weighed at D0 and D21.Pasteurella multocida,Actinobacillus pleuropneumoniae, andMycoplasma hyopneumoniaewere mainly identified in the pig lungs. The difference in the cure rate (74.5% in marbofloxacin groupversus68% in the amoxicillin group) was not significant. Mean rectal temperature was significantly lower after treatment with marbofloxacin. Other criteria tended to be favourable for the marbofloxacin group, although differences were not significant. The time to cure tended to be shorter for the marbofloxacin group (24.3% of pigs at 24 hours post‐treatmentversus12.1% in the amoxicillin group). Marbofloxacin and amoxicillin relapse rates were 11.9% and 17.2% respectively (not significant) and daily weight gain was 746 g in the marbofloxacin groupversus687 g in the amoxicillin group (not significant). The 2% marbofloxacin solution was significantly better tolerated than amoxicillin.

ISSN:0165-2176    

DOI:10.1080/01652176.2000.9695041

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Hypomagnesaemic tetany in cows develops occasionally after an acute increase in K intake such as can occur when cows are transferred to spring grass. There is evidence that under these conditions plasma Mg concentrations are only transiently decreased. In this study the questions addressed were whether the plasma Mg concentration, indeed adapts to a high K intake as only dietary variable, and whether urinary Mg excretion is associated with this adaptation. Dry cows were fed rations containing either 26 or 50 g K/kg dm, the extra K being in the form of KHCO3. When the cows were acutely transferred from the low to the high K ration, plasma Mg concentrations fell slightly, but significantly from 0.86 to 0.76 mmo1/1 within five days, but rose again to 0.80 mmo1/1 after another 23 days, this rise being also statistically significant. None of the animals developed tetany. The decrease in plasma Mg concentration in individual animals after five days on the high‐K ration ranged from 6 to 21 %. The time course of urinary Mg excretion resembled that of plasma Mg concentration; minimum Mg excretion was seen after four to six days on the high‐K ration with a subsequent increase thereafter. To explain the transient lowering of plasma Mg concentration, it is suggested that the K‐induced decrease in Mg status caused a delayed increase in the carrier‐mediated component of Mg absorption, which in turn caused an increase in urinary Mg excretion. When the cows were acutely switched from the high to the low K ration, plasma Mg concentration and urinary Mg excretion rose, but no transient changes were seen.

ISSN:0165-2176    

DOI:10.1080/01652176.2000.9695042

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

In the period 1993–1998, digital carcinomas in 64 cats were examined. In all animals primary complaints were painful digit(s). Eight cats had a primary squamous cell carcinoma which involved one digit or two adjacent digits of one leg. Fifty‐six cats had metastases of a pulmonary carcinoma in the digits, and in general multiple digits of different legs were involved. In many of these cats metastases also occurred in other organs, including the skin and muscles. No primary sweat gland carcinomas of the digits were seen. Primary squamous cell carcinomas of the digits were characterized by cornification and the absence of PAS‐positive cells, PAS‐positive secretory material. Immunohistochemically, these neoplasms stained negative with the monoclonal antibody CAM 5.2 directed against Keratin 8 (K 8). The metastases of pulmonary carcinomas to the digits showed one or more of the following histological features: goblet cells, ciliated epithelial cells, PAS‐positive cells or lakes, and/or a PAS‐positive lining of luminal membranes and no cornification. Immunohistochemically, they showed positive staining for CAM 5.2 (K8).

ISSN:0165-2176    

DOI:10.1080/01652176.2000.9695043

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Reports on the effects of mange on the production performance of pigs are conflicting. So far, studies have used experimental infections, by depositing encrusted lesions from chronically infected pigs into the ears of experimental pigs. However, this is a poor representation of what happens under natural field conditions. The purpose of our study was to quantify the effects of sarcoptic mange on production performance and pruritus in pigs that were infected by contact withS. scabiei var. suis‐infected pigs. A total of 80 piglets were matched by sex and weight and randomly divided between experimental and control compartments. In the experimental compartment, each of three naturallyS. scabiei var. suis‐infested pigs were randomly allocated to three pens with 13 susceptible pigs each. From day 0 to 35, the growth performance of pigs in the experimental compartment was significantly (P=0.04) worse (35 g/d) than of pigs in the control compartment. From day 35 to 112, there was a statistical trend (P=0.10) that the growth performance of pigs in the experimental compartment was lower (50 g/d) than that of pigs in the control compartment. For the complete fattening period (0–112 or more days), the growth performance of pigs in the experimental compartment was significantly (P=0.05) worse (41 g/d) than that of pigs in the control compartment. Mean feed conversion ratio (kg feed per kg gain) was 2% higher in the experimental compartment compared with the control compartment. Pigs in the experimental compartment had a nine times (95% CI: 2 ‐ 44) higher chance of showing pruritic behaviour than pigs in the control compartment.

ISSN:0165-2176    

DOI:10.1080/01652176.2000.9695044

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The use of a vaccine against classical swine fever virus (CSFV) during an outbreak of CSF should lead to a reduction in the horizontal or vertical transmission of CSFV. The reduction of vertical, i.e. transplacental, transmission of a moderate‐virulent strain of CSFV from the sow to its offspring was studied in sows vaccinated once or twice with a CSFV E2subunit vaccine. Two groups of nine sows were vaccinated with one PD95dose of the E2subunit vaccine, approximately four weeks before insemination. A third group of nine inseminated sows served as controls. One group of nine sows were vaccinated again at two weeks after insemination. At ten weeks after the primary vaccination, approximately six weeks after insemination, all 27 sows were challenged intranasally with 105TCID50of a moderate‐virulent strain of CSFV, the Van Zoelen strain. The sows were euthanized at five weeks after challenge, and samples from the sows and fetuses were collected for detection of CSFV. All 27 sows were in gestation at the time of slaughter, CSFV was detected in the fetuses of all unvaccinated sows but it was not detected in any of the samples collected from fetuses of the double‐vaccinated sows. Virus was however recovered from the fetuses of one out of nine sows vaccinated once. All the sows, except four double‐vaccinated sows, developed CSFV Ernsantibodies. Transplacental transmission of CSFV was reduced significantly (p <0.001) in all vaccinated sows. When the results from the experiment were extrapolated to a herd level, it could be concluded that, with 95% certainty, approximately 11% (single vaccination) or 0% (double vaccination), confidence intervals of 0.01–0.44 and 0.0–0.30 respectively, of the pregnant sows would still not be protected against vertical transmission of moderate‐virulent CSFV.

ISSN:0165-2176    

DOI:10.1080/01652176.2000.9695045

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

This study describes the occurrence of fibrocartilaginous embolism of the spinal cord (FCE) in eight juvenile Irish Wolfhounds that were presented within a period of 16 months (1996–1997). The dogs, seven males and one female between eight and 13 weeks of age, were presented because of an acute onset of abnormal locomotion. Five dogs were euthanized and FCE was diagnosed by the histomorphological presence of focal myelomalacia and Alcian blue‐positive‐nucleus‐pulposus material in the spinal cord vasculature. Three dogs, which were thought to have FCE because of their clinical symptoms, improved with partial or almost complete return to normal locomotion. Although the observed high incidence may be a coincidence, oral information from breeders and lay reports of similar cases in journals for dog breeders from various countries suggest that FCE is a common disorder in young Irish Wolfhounds.

ISSN:0165-2176    

DOI:10.1080/01652176.2000.9695046

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The prophylactic effect of in‐feed medication of conventional pigs with sulphadimethoxine (SDM), sulphamethoxazole (SMX), and trimethoprim (TMP) was tested by using anActinobacillus pleuropneumoniaeinfection model. In each of five experiments, six pigs were given medicated feed twice daily and three pigs received antibiotic‐free feed and served as positive (unmedicated, infected) controls. The following drugs or drug combinations were tested (in mg per kg feed): 500 SDM + 100 TMP, 500 SMX + 100 TMP, 125 SMX + 25 TMP, 125 SMX (alone) and 25 TMP (alone). After six days of feed medication, all animals were endobronchially inoculated withA. pleuropneumoniaein a dose of 1–3.104colony‐forming units (CFU). The response to the challenge in all control pigs was characterized by fever, lethargy, anorexia, reduced water consumption, and laboured breathing. At autopsy all controls manifested a fibrinous haemorrhagic pleuropneumonia. In‐feed medication with 500 SDM + 100 TMP, 500 SMX + 100 TMP as well as 125 SMX + 25 TMP resulted in an effective protection against the challenge in all treated animals. After consumption of feed medicated with 125 mg per kg SMXor25 mg per kg TMP, pleuropneumonia was evident in all challenged pigs. The results of this study indicate anin vivopotentiation of SMX and TMP in pigs against this respiratory tract pathogen.

ISSN:0165-2176    

DOI:10.1080/01652176.2000.9695047

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor