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71.
Prevalence of mycoplasmas in the respiratory tracts of pneumonic calves.   总被引:2,自引:0,他引:2  
The prevalence of mycoplasmas in the respiratory tracts of 148 pneumonic calves originating from 25 herds in the Netherlands is reported. Four types of culture media were used to isolate mycoplasmas: solid modified Edward medium, 2 types of Friis media, and A7B differential agar medium. Mycoplasmas were isolated both from nasal swab specimens and lung lavage fluids collected from live calves and from nasal mucosa and lung tissue specimens collected post mortem. All of the mycoplasma strains isolated could be identified as either Ureaplasma diversum (isolated from 80% of 25 herds), Mycoplasma dispar (92%), M. bovirhinis (88%), M. bovis (20%), M. bovigenitalium (4%), M. arginini (16%), or M. canis (12%). Isolation rates of M. dispar and U. diversum were considerably higher from lung lavage fluids than from nasal swab specimens. M. bovis was detected only in fattening herds and not in dairy herds. The respiratory tracts of 75% of the calves examined contained at least 2 mycoplasma species. In total, 25 different combinations of mycoplasma species were detected in specimens collected from noses and lungs. The pathogenic species U. diversum and M. dispar had not been isolated before in the Netherlands.  相似文献   
72.
Aspects of intensive management practices such as high-yielding cultivars, narrow-row spacings and fungicide treatments could potentially increase cereal yields in regions with a short crop-growing season and occasionally dry and hot weather. A field experiment was carried out at McGill University, Canada for three years (1987 to 1989) to test the effects of triadimefon (1-[4-chlorophenoxy]-3,3-dimethyl-1-[1H-1,2,4-triazol-1-yl]-2-butanone, or Bayleton, a trade name) fungicide (0 vs. 140 g a.i. ha−1) and row spacing (10 vs. 20 cm) on the yield components, yield and other agronomic traits (spike emergence, days to maturity, leaf disease and plant height) of spring barley ( Hordeum vulgare L.) cv. Cadette, Laurier and Leger. A cultivar by row spacing interaction resulted in a 11 to 13.5 % increase in grain yield due to narrow rows for Laurier in two out of the three years and up to 16 % for Leger in one year. Over the three years grain yields were on average increased 6 to 12 % due to use of the narrower row spacing. Fungicide application to barley at the early heading stage effectively controlled leaf diseases without influence on yield components or grain yield. Our results indicate that some components of intensive management such as narrow row spacing can be applicable in regions with a short crop-growing season.  相似文献   
73.
Equine arteritis virus (EAV), a non-arthropod borne togavirus, has been shown to have a global distribution. To date, no major antigenic variation has been demonstrated between EAV isolates from different geographic origins. In this study, the genomic RNA of EAV isolates obtained from horses of different breeds in various countries around the world was oligonucleotide fingerprinted. Comparisons of these fingerprints were used to determine the extent of genomic variation among such isolates. Comparisons among isolates from North American horses revealed, for the most part, oligonucleotide homologies of less than 60%. Only 29 of the 98 comparisons revealed greater than 60% oligonucleotide homology. Nonetheless, several comparisons indicated a close epidemiologic relationship between isolates from horses of different breeds located in different states. Though all European isolates were of Standardbred origin and were from horses located in northern European countries, the majority had oligonucleotide homologies of less than 60%. Where oligonucleotide homology was apparent, it was, with one exception, greater than 70%. The two isolates from New Zealand had 93.2% oligonucleotide homology. This is indicative of an extremely close epidemiologic relationship. Comparisons between EAV isolates from around the world revealed oligonucleotide homologies between viruses from North America, Europe and New Zealand. In several instances, this homology was greater than 70% and in one case greater than 80%. No oligonucleotide homology was evident in comparisons involving the virus from South Africa. The high level of genomic conservation between certain EAV isolates of disparate geographic origins may reflect dissemination of the virus associated with the international movement of horses. The extent of genomic variation demonstrated between most of the EAV isolates used in this study confirms the need for further investigation of genomic heterogeneity among strains of this virus before techniques that rely upon nucleic acid hybridization can be effectively applied as diagnostic procedures.  相似文献   
74.
Male and female Sprague-Dawley rats were given CGS 21595, a pro-drug that is almost immediately metabolized to CGS 19213, a naphthoquinone that acts as a 5-lipoxygenase inhibitor. The compound was administered by gavage to five groups of Sprague-Dawley rats (group Nos. 1, 5, n = 30; group Nos. 2-4, n = 20) at daily doses of 0, 50, 150, 500, or 1,000 mg/kg for 13 weeks. Rats in the higher dose groups had a reduced weight gain, but significant neurologic signs were not observed. A peripheral neuropathy consisting predominantly of myelin destruction in the spinal nerve roots and sciatic nerves in male rats treated with greater than or equal to 150 mg/kg CGS 21595 and in female rats treated with greater than or equal to 50 mg/kg CGS 21595 for 13 weeks. This lesion was not fully reversible after a recovery period of 4 weeks. Lesions consisted of ballooning of myelin sheaths, infiltration by macrophages, demyelination, and occasional areas of remyelination. Axons were generally preserved, and the brain and spinal cord were not affected. Male and female rats in all treatment groups had cytoplasmic hyaline droplets in the proximal renal tubules. This change was reversible after 4 weeks and was not associated with any other adverse effects on the kidney.  相似文献   
75.
Abstract  The accuracy of household reporting of subsistence fishing catch and effort and seafood consumption on the Fijian island of Ono-i-Lau was studied. A creel survey was carried out concurrently to validate the household survey data. Reported estimates of fishing participation, effort, and fish consumption were not significantly different to the creel survey estimates. Householder's appeared to overestimate the number of fish from the most abundant family Lethrinidae, and underestimate rarer fish. However, there was no significant difference between the reported and observed contribution of the majority of finfish families and invertebrate taxa. The reported and observed catch rate estimates were not significantly different, indicating that Ono-i-Lau villagers are relatively accurate in their estimation of the number and size of fish from recalled catches.  相似文献   
76.
To develop an appropriate cryopreservation protocol for spermatophores of black tiger shrimp, Penaeus monodon, three cryoprotectants (dimethyl sulphoxide (DMSO), methanol (MeOH) and ethylene glycol (EG)) at two concentrations (5% and 10%) were examined. Artificial implantation of spermatophores was also carried out to assess the fertilizing ability of fresh and post‐thaw spermatophores. Spermatophores were collected during consecutive regenerations (15‐day intervals) and assessed for qualitative and quantitative changes and also for fertilizing ability by implantation. The mean fertilization rate for artificial insemination using post‐thaw spermatophore was 79.9±3.7%, lower than the fertilization rates observed for artificial implantation using fresh spermatophore and natural mating. Mean hatch rates for fresh spermatophore, frozen‐thawed spermatophore and natural mating were 88.8±0.6%, 87.8±0.4% and 88.3±0.5%, respectively; and there was no difference among the three groups. The mean fertilization rate of spermatophores collected during the first stripping was higher (90.6±0.6) than during the second stripping (85.7±2.6), but the mean hatch rate was not different between the two strippings. The highest mean sperm viability (79.7±0.4%) was obtained from DMSO (5%), with no survival observed in the 10% MeOH treatment. Spermatophore weight, total sperm count and percentage of abnormal sperm were not different between spermatophores collected at the first and second stripping. This is the first study to report high fertilization and hatch rates from cryopreserved spermatophore using artificial implantation of spermatophore before spawning.  相似文献   
77.
Dogs (n = 13), which had failed to be cured of giardiosis following chemotherapeutic measures, were treated with a Giardia vaccine (2-3 injections). Clinical signs resolved between 16 and 42 days postvaccination and cessation of fecal cyst shedding was between 21 and 70 days. Vaccination is a potential method of treating giardiosis in dogs.  相似文献   
78.
The use of phytotherapy to treat human diseases has its roots in pre-historical times. Despite the modern advances achieved in the field of synthetic chemistry, the most efficient drugs available have their genesis directly or indirectly related with the vegetal kingdom. Indigenous communities have long used plant extracts to treat illnesses. Many of these extracts have shown effective action, with new bioactive compounds being extracted and screened every year. These extracts have also proven to be good sources of therapeutic agents to the treatment of Leishmaniasis. This work highlights some of these agents, while trying to emphasize the importance of plants as a source of new and powerful drugs against this widespread disease.  相似文献   
79.
The French fisheries management regime is based on public and private ownership of fishing waters associated with a complex multilevel management system. A total of 730 operational commercial inland fisheries were examined by analysis of thematic interviews and questionnaires. Commercial fishermen are beginning to understand the nature of their own activity and its relationship to the concept of sustainable management. Nevertheless, fishermen have to face two major problems: first, they are poorly represented on decision making bodies where anglers are dominant, and secondly their activities are governed by two separate ministries. Opportunities for future development may lie in decision making at the catchment level.  相似文献   
80.
In order to survey the behaviour of choosing the alley area instead of a cubicle as a lying place (cubicle refusal), a questionnaire was sent to the 273 dairy farms in Norway known to keep cows in cubicle housing systems. Sixty-six percent of the farmers contacted were included in the study. The median herd size was 18 cows (range 7-118). More than 85% of the herds had sheds providing one or more cubicles per cow. The mean herd occurrence of cubicle refusal was 6%, but showed great variation (range 0-55%). Regression analysis showed a significant association between rearing heifers in slatted floor pens and an increased cubicle refusal occurrence (p = 0.02, R2 = 0.05), while herd size, use of litter, or cubicle-to-animal ratio were not found to be associated with cubicle refusal. The practice of rearing heifers in slatted floor pens accounted for about one half of the observed cubicle refusal (etiologic fraction = 0.51).  相似文献   
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