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 etiological 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. hyosynoviae, M. hyopneumoniae,andAcholeplasma 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 characterised as a virus and designated Lelystad virus. No relationship between this virus and other viruses has yet been established. Of 165 sows reportedly afflicted 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 the known viral pathogens. Antibodies directed against Lelystad virus were also found in pigs with mystery swine disease in England, Germany and in the United States. We conclude that infection with Lelystad virus is the likely cause of mystery swine disease.

ISSN:0165-2176    

DOI:10.1080/01652176.1991.9694296

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Aerosol exposure of eight pregnant sows to cell‐culture‐ propagated Lelystad virus resulted in clinical signs characteristic of so‐called mystery swine disease. After an incubation of 4–7 days, all sows were inappetant and listless for 6–9 days. Two sows developed a transient red‐blue discolouration of the ears ('abortus blauw’ or blue ear disease) accompanied by abdominal respiration, and two had a fever for one day only.

ISSN:0165-2176    

DOI:10.1080/01652176.1991.9694297

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The pathogenicity and pathogenesis of Lelystad virus was studied in six 6‐day‐old SPF piglets. A third passage of the agent was propagated on porcine alveolar macrophages and intranasally inoculated into pigs. Pigs were killed at hours 24, 48, 60, and 72, and on days 6 and 8 after inoculation. From day 2 on pigs developed diffuse interstitial pneumonia with focal areas of catarrhal pneumonia, and from this day on splenic red pulp macrophages were enlarged and vacuolated. Lelystad virus was re‐isolated from the lungs of infected pigs from day 2 after inoculation. Lelystad virus antigens were detected by immunohistochemical techniques in bronchiolar epithelium and alveolar cells, and in spleen cells of infected pigs from day 2 after inoculation. Ultrastructural examination of tissues by electron microscopy revealed degenerating alveolar macrophages and epithelial cells in lungs and nasal mucosa, with excessive vacuolation of the endoplasmic reticulum.

ISSN:0165-2176    

DOI:10.1080/01652176.1991.9694298

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Administration of 6 IU synthetic ACTH1–24intravenously to six Holstein‐Friesian cows resulted in a cortisol peak concentration after I hour of 148 ± 34.2 ng/ml. Basal plasma cortisol concentration (4.84 ± 0.83 ng/ml) was reached 5 hours after ACTH injection.

ISSN:0165-2176    

DOI:10.1080/01652176.1991.9694299

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Plasma disposition, metabolism, protein binding and renal clearance of sulphamethoxazole (SMZ) and trimethoprim (TMP) were studied in four pigs after intravenous administration at a dose of 40 and 8 mg/kg, respectively. SMZ and TMP were quickly eliminated (mean elimination half‐lives: 2.7 and 2.4 h, respectively). SMZ was predominantly acetylated; no hydroxy and glucuronide derivates could be detected in plasma and urine. TMP was 0‐demethylated into 4‐hydroxytrimethoprim (M1) and 3‐hydroxytrimethoprim (M4) metabolite and subsequently extensively glucuronidated. SMZ, TMP and its M1metabolite were excreted predominantly by glomerular filtration, while N4‐acetylsulphamethoxazole and glucuronide conjugates of the M1and M4metabolites of TMP were actively eliminated by tubular secretion. The proportional drug percentage being present in the urine as parent compound was 13.1% for TMP and 16.0% for SMZ. The glucuronide conjugates of the M1and M4metabolites formed the main part (81.5%) of urinary TMP excretion pattern.

ISSN:0165-2176    

DOI:10.1080/01652176.1991.9694300

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

To study the possible role of endotoxin in the pathogenesis of bovine laminitis, local and systemic injections of endotoxin (E. coli 0111 B4) with different doses were given to three groups of four cows each. Clinical and haematologic parameters indicated an acute‐phase response, including positive plasma ethanol gelation (soluble fibrin), the occurence of fibrin degradation products and decreased thrombocyte counts. Local Shwartzman reactions were not evoked. Clinical examination of the claws and the gait of the animals revealed no signs of laminitis. However, on histopathological examination of the claw corium signs of laminitis such as vacuolisation of the Stratum basale, lymphocyte and leucocyte infiltration and thrombosis were found. These results indicate that endotoxin indeed may be involved in the pathogenesis of laminitis. For the development of a clinical acute laminitis model in cattle either another dosage, other toxins or factors in addition to the endotoxin used in this experiment are needed.

ISSN:0165-2176    

DOI:10.1080/01652176.1991.9694301

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

This review deals with the features of clinical and subclinical laminitis in cattle. Prominent clinical signs of acute laminitis are a tender gait and arched back. The sole horn reveals red and yellowish discolourations within five days. In subacute and chronic cases clinical signs are less severe. In chronic laminitis the shape of the claws is altered. Laminitis is frequently followed by sole ulceration and white zone lesions.

ISSN:0165-2176    

DOI:10.1080/01652176.1991.9694302

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

In two sanitation trials it was not possible to rear seronegative animals within a breeding and rearing herd heavily infected withActinobacillus pleuropneumoniaeserotype 2.

ISSN:0165-2176    

DOI:10.1080/01652176.1991.9694303

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Sulpha‐2‐monomethoxine is N4‐acetylated to an extent of 12% of the dose by Pseudemys scripta elegans; 48% is excreted unchanged. No O‐dealkylation of the 2‐methoxy group takes place.

ISSN:0165-2176    

DOI:10.1080/01652176.1991.9694304

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Calf‐cow records from 1081 replacement heifers raised on 42 specialised rearing farms in the province of Noord‐Brabant have been analysed. The predominant breed was Meuse‐Rhine‐Yssel (MRY). The objective was to study the relationship between weight and age at first calving and milk production in subsequent lactations, herd life span, dystocia and first calving interval.

ISSN:0165-2176    

DOI:10.1080/01652176.1991.9694305

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor