Clostridial myositis following ivermectin administration          下载免费PDF全文

Nation PN  Frelier PF  Schoonderwoerd M 《The Canadian veterinary journal. La revue veterinaire canadienne》1983,24(9):295

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Terminal ileitis in lambs   总被引：1，自引：1，他引：0       下载免费PDF全文

Chalmers GA  Nation PN  Pritchard J 《The Canadian veterinary journal. La revue veterinaire canadienne》1990,31(4):292-295

Terminal ileitis was diagnosed in three flocks of lambs in different areas of Alberta. Salient clinical features in affected lambs were progressive emaciation with diarrhea, and in some lambs, frequent abdominal stretching. Postmortem findings included thickening of the ileal, and in some animals, the jejunal, cecal and colonic mucosa as a result of mucosal infiltrates of many lymphocytes and fewer plasma cells, eosinophils, globular leukocytes, and neutrophils. Hyperplasia of intestinal lymphoid tissue was prominent in most affected lambs. The cause of the condition is unknown.  相似文献   

Problems associated with the depopulation of tuberculosis-infected wapiti herds          下载免费PDF全文

Nation PN 《The Canadian veterinary journal. La revue veterinaire canadienne》1999,40(2):88

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The application of granular pesticides     

H. J. Nation 《Pest management science》1972,3(6):771-780

Three basic processes are involved in the application of granular pesticides—metering, transporting and distributing. Metering may be simply dependent upon flow through an orifice under gravity but preferably force-feed mechanisms, usually driven in relation to forward speed are used. Transport may be effected merely under gravity, but pneumatics is also an accepted method particularly for large swath widths. Kinetic energy is also an agency in transporting granules as in “throwing” type distributors and this also achieves the distribution element. With gravity and pneumatic transport the final distribution is usually by spreaders or by nozzles at each outlet. Assessment of performance is rendered difficult by the very small size of the particles to be detected and the very low rates of application usually employed. Data are required on the appropriate sampling areas which should be used in assessing uniformity of distribution and the significance of the variations measured. Cooperation between all the disciplines of workers in the field is necessary for further development of the technique and in particular in the field of formulation a valuable contribution would be in the reduction in the diversity of physical properties of all the granular materials in use or projected.  相似文献   

Accuracy of bovine pregnancy detection using transrectal ultrasonography at 28 to 35 days after insemination   总被引：4，自引：0，他引：4  

Nation DP  Malmo J  Davis GM  Macmillan KL 《Australian veterinary journal》2003,81(1-2):63-65

OBJECTIVE: To estimate the accuracy of real-time ultrasonography to detect pregnancy in dairy cows at 28 to 35 days after insemination. METHODS: Cows that did not return to oestrus between 18 and 24 days after a first insemination (n = 526) were examined by transrectal ultrasonography from 28 to 35 days after insemination. Pregnancy was confirmed by the observation of a foetus, but fluid in the uterine horn and the presence of embryonic membranes were also noted. When pregnancy was not confirmed by the observation of a foetus, a second examination 7 days later, confirmed these remaining cows as pregnant or not pregnant to the first insemination. Detection of pregnancy at this early examination was compared with manual transrectal pregnancy examination performed 10 to 13 weeks after insemination (13-week examination). RESULTS: There were 44% of cows that were pregnant to the first service, 34% that had returned for a second service 18 to 24 days after the first insemination, and 20% of cows that were not pregnant, and had not returned normally for a second service (non-pregnant, non-return) within 24 days of their initial insemination. The presence of a foetus at 28 to 35 days after insemination was accurately predicted by a simplified method where uterine fluid accumulation and embryonic membranes were observed. Foetal loss between the early detection and the 13-week examination (9% of pregnancies) indicated that 28 to 35 days post insemination was too early to reliably detect pregnancy. CONCLUSION: Early examination of pregnancy with transrectal ultrasonography is an accurate method to identify non-pregnant, non-return cows. The examination can be simplified by the observation of uterine fluid accumulation and embryonic membranes, as opposed to the more involved process of observing the foetus.  相似文献   

Prevalence of Faecal Pathogens in Calves of Racing Camels (Camelus dromedarius) in the United Arab Emirates     

Moore JE  McCalmont M  Xu J  Nation G  Tinson AH  Crothers L  Harron DW 《Tropical animal health and production》2002,34(4):283-287

Tropical Animal Health and Production -  相似文献   

Development and evaluation of a rapid absorbed enzyme immunoassay test for the diagnosis of Johne''s disease in cattle   总被引：8，自引：0，他引：8  

JC COX  DP DRANE  SL JONES  S. RIDGE†  AR MILNER† 《Australian veterinary journal》1991,68(5):157-160

An absorbed enzyme immunoassay (EIA) test for Johne's disease in cattle was developed in which absorption of cross-reacting antibodies occurred as a rapid reaction in solution rather than overnight with whole organisms and a subsequent centrifugation step. Total test time was reduced to less than 2 h with a minimum of manipulations. The test was evaluated in cattle herds from Johne's disease-endemic and Johne's disease-free regions of Australia. Specificity was 99.8%. Calculations of sensitivity were affected by the history of the herd under test. However, the EIA detected in excess of 80% of animals before onset of clinical disease and 65% of faecal shedders were EIA positive on, or before, first detection of Mycobacterium paratuberculosis in their faeces. The test should aid epidemiological studies and be a useful tool in the management and control of Johne's disease.  相似文献   

A High-Temperature Electrical Conduction Mechanism in the Lower Mantle Phase (Mg,Fe)1-xO     

DP Dobson  NC Richmond  JP Brodholt 《Science (New York, N.Y.)》1997,275(5307):1779-1781

Measurements of electrical conductivity at high pressure and temperature were taken on the lower mantle phase magnesiowustite with varying Fe3+ content. Although previous measurements at atmospheric pressure suggest Fe2+-Fe3+ hopping (small polaron) as the dominant conductivity mechanism, the present experiments show a change in charge transport mechanism with temperature. The lower temperature measurements are consistent with small polaron conduction, but at higher temperatures, which are more applicable to the lower mantle, a large polaron mechanism is suggested. Because these mechanisms have different temperature and compositional dependencies, this transition has important implications for extrapolation to mantle conditions.  相似文献   

Synthesis of Novel Thin-Film Materials by Pulsed Laser Deposition     

DH Lowndes  DB Geohegan  AA Puretzky  DP Norton  CM Rouleau 《Science (New York, N.Y.)》1996,273(5277):898-903

Pulsed laser deposition (PLD) is a conceptually and experimentally simple yet highly versatile tool for thin-film and multilayer research. Its advantages for the film growth of oxides and other chemically complex materials include stoichiometric transfer, growth from an energetic beam, reactive deposition, and inherent simplicity for the growth of multilayered structures. With the use of PLD, artificially layered materials and metastable phases have been created and their properties varied by control of the layer thicknesses. In situ monitoring techniques have provided information about the role of energetic species in the formation of ultrahard phases and in the doping of semiconductors. Cluster-assembled nanocrystalline and composite films offer opportunities to control and produce new combinations of properties with PLD.  相似文献   

Detoxication capacity in the honey bee,Apis mellifera L     

S.J. Yu  F.A. Robinson  J.L. Nation 《Pesticide biochemistry and physiology》1984,22(3):360-368

Various detoxifying enzymes, including microsomal oxidases, glutathione S-transferases, esterases, epoxide hydrolase, and DDT-dehydrochlorinase, were assayed in adult worker bees (Apis mellifera L.) using midguts as the enzyme source. A cell-free system was used for all enzyme assays, except that microsomal oxidases required intact midgut because of the inhibitor encountered. Midgut microsomal preparations contained mainly cytochrome P-420, the inactive form of cytochrome P-450, which may explain the low microsomal oxidase activity in microsomes. All enzymes studied were active, suggesting that the high susceptibility of honey bees to insecticides is not due to low detoxication capacity. Sublethal exposure of honey bees to various insecticides had no effect on these enzyme activities, with the exception of permethrin which significantly stimulated the glutathione S-transferase, and malathion, which significantly inhibited the α-naphthylacetate esterase and carboxylesterase.  相似文献