Evaluation of methods used for detecting Streptococcus suis type 2 in tonsils, and investigation of the carrier state in pigs   总被引：4，自引：0，他引：4  

P R Davies  C J Ossowicz 《Research in veterinary science》1991,50(2):190-194

Streptococcus suis type 2 was isolated from the tonsils of 143 (76 per cent) of 188 pigs from three herds by culturing on media containing a specific antiserum. Culture of frozen sections of tonsillar tissue was more sensitive than culture of swabs or deep scrapes. The specificity of an indirect fluorescent antibody test for identifying S suis type 2 in mixed cultures was conservatively estimated to be 0.89. The level of infection in one herd without a history of meningitis was lower than in two herds which had experienced repeated outbreaks. Differences between herds in the level of infection were due to differences in the number of organisms carried by pigs, more so than differences in the detectable carrier rate.  相似文献   

Musculoskeletal Growth Gradients: A Contribution to Quadrupedal Mechanics     

A. S. Davies 《Anatomia, histologia, embryologia》1979,8(2):164-167

Postnatally, the axial skeleton of the pig shows peaks of high relative growth at the sites of attachment of the fore and hindlimbs, corresponding to the regions of highest relative growth in the limbs. This supports the concept that musculoskeletal growth gradients are a propulsive adaptation.  相似文献   

Use of limestone wastes from metal mining as agricultural lime: potential heavy metal limitations     

B. E. Davies  C. F. Paveley  B. G. Wixson 《Soil Use and Management》1993,9(2):47-52

Abstract. Finely ground limestone waste from lead mining is discarded as useless but could be a valuable alternative to agricultural limestone. A glasshouse pot experiment established that it is an effective liming material. Two kinds were used: one from north Wales (HMT) represented metal-rich waste produced by the older water-gravity separation of ores; the other (NLB) was a modern flotation tailings. A commercial lime (CLS) was used for comparison. The materials were applied to an acid soil in quantities sufficient to raise the pH to 7 (single liming) and at much greater rates equivalent to annual limings for 369 years. All treatments were replicated five times and the soil/lime mixtures were analysed for EDTA-extractable lead, zinc and cadmium. Radish was grown as the test plant and hypocotyl and leaf tissue were analysed for the same metals. The larger additions of HMT and NLB caused chlorosis and decreased yields. The cadmium and lead concentrations of leaves and hypocotyls suggested that the HMT material could be safely applied to soil annually for 79 years and NLB for 277 years. It is concluded that NLB can be used as agricultural limestone.  相似文献   

The antibody response in sheep vaccinated with experimental Nairobi sheep disease vaccines     

F. G. Davies  S. Otieno  D. M. Jessett 《Tropical animal health and production》1977,9(4):181-183

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The effect of vaccination of lambs with live parainfluenza virus type 3 on pneumonia produced by parainfluenza virus type 3 and Pasteurella haemolytica     

D H Davies  A R McCarthy  R A Penwarden 《New Zealand veterinary journal》1980,28(10):201-202

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Combinations of pirimiphos-methyl and carbaryl for stored grain protection     

Richard A. H. Davies  James M. Desmarchelier 《Pest management science》1981,12(6):669-677

In laboratory experiments, whole wheat was treated with pirimiphos-methyl or carbaryl or combinations of these two insecticides; the treated grain was then adjusted to a 12% moisture content and stored at 25°C for bioassay at various intervals over a period of 39 weeks. Pirimiphos-methyl at 5.1 mg kg^?1 effectively controlled Sitophilus granarius (L.) and Tribolium confusum Jacquelin du Val but was ineffective against Rhyzopertha dominica (F.) CRD 118, a strain showing malathion resistance. Conversely, carbaryl at 6.5 mg kg^?1 (but not at 3.1 mg kg^?1) was effective against R. dominica, but ineffective against the other two species. A combination of pirimiphosmethyl + carbaryl, at 1.8 + 5.1 mg kg^?1, controlled S. granarius and R dominica but not T. confusum, whilst a 4.2 + 3.4 mg kg^?1 combination was relatively more effective against T. confusum but less so against R. dominica. In a separate experiment, whole wheat was treated with carbaryl at 2.5, 5.0 and 7.5 mg kg^?1 (nominal rates). Samples were stored and, at various times after the treatments, were bioassayed with R. dominica CRD 2, at 20, 25, 30 and 35°C. The results were comparable with those for the CRD 118 strain, but efficacy was reduced at higher temperatures. The combination of pirimiphos-methyl at 4–5 mg kg^?1 and carbaryl at 5–6 mg kg^?1 is suggested as a potentially useful grain protectant where R. dominica is a problem and long term storage is required. These results are discussed in relation to the protection of stored grain in Australia.  相似文献   

Alkyl aryl ketone oxime O-ethers: A novel group of pyrethroids     

Michael J. Bull  J. Hugh Davies  Robert J. G. Searle  Arthur C. Henry 《Pest management science》1980,11(2):249-256

The alkyl phenyl ketone oxime O-benzyl ethers are a new group of insecticidal compounds. Although they lack the ester linkage, they resemble the pyrethroids in general, and the esters of 2-phenylalkanoic acids, in particular fenvalerate, because they show similar physiological effects on isolated nerve preparations and on whole insects; they also show a similar pattern of change of biological activity in response to structural change. The compounds may exist as two geometric isomers, of which only the (E) series shows significant biological activity; this observation appears to have some bearing on the relationship between conformation and activity in the pyrethroid series as a whole.  相似文献   

The laboratory diagnosis of lumpy skin disease   总被引：2，自引：0，他引：2  

F G Davies  H Krauss  J Lund  M Taylor 《Research in veterinary science》1971,12(2):123-127

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世界猪病的发展与演变(续)     

冯汉利  吴斌 《养殖与饲料．饲料世界》2003,(3):44-46

17 群体水平上的复合病因网络 在集约化生产系统中,我们面临的大多数疾病都有着复杂的成分因素。其中一些可能是必要因素,如果没有他们的存在疾病也就无从发生,但当他们独自起作用时却并不是充分原因。“Koch’s”假设有其局限性,只有对疾病病因作现场检验时才起作用。那些病原单独存在并且是必要充分原因的疾病通常是最易  相似文献   

Effectiveness of the (+)-trans-chrysanthemic acid ester of (±)-allethrolone (bioallethrin) against four insect species     

Mary S. Davies  P. R. Chadwick  J. M. Holborn  D. C. Stewart  J. C. Wickham 《Pest management science》1970,1(6):225-227

The activity of the (+)-trans-chrysanthemic acid ester of (±)-allethrolone (Bio-allethrin) is shown to be superior to that of the (±)-cis, trans-isomers (allethrin), against houseflies, two species of grain beetle and larvae of the yellow fever mosquito. The efficiency of the (+)-trans-isomer compares favourably with that of pyrethrins when each is used alone or with piperonyl butoxide.  相似文献