• Fitting the Gompertz function to dose-response data of larval tick populations 

  Spickett, Arthur M.; Van Ark, H.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  Samples of 6, 1st generation larval populations of Boophilus decoloratus, originating from field collected females, were subjected to increasing doses of the organophosphate acaricide, Dioxathion. The dose-response ...
• Pyridoxine (a vitamin B6) and its derivative pyridoxal as treatment for Albizia versicolor poisoning in guinea-pigs 

  Gummow, Bruce; Erasmus, G.L.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  In the course of three experiments it was established that all the toxic effects of a lethal dose of Albizia versicolor pods (> 4,5g/kg) in guinea-pigs could be countered by concurrent subcutaneous injection of pyridoxine ...
• Evaluation of the efficacy of anthelmintics against parafilariosis in cattle 

  Groeneveld, Hendrik T.; Van Wyk, Jan Aucamp; Carmichael, I.H.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  Parafilariosis was first described in South Africa in 1964, thereafter being discovered at numerous localities in the country. When it became obvious that Parafilaria bovicola, for which no treatment was known, caused ...
• Heat stress in dairy cattle and other livestock under southern African conditions. III. Monthly temperature-humidity index· mean values and their significance in the performance of dairy cattle 

  Du Preez, J.H.; Hattingh, P.J.; Giesecke, W.H.; Eisenberg, B.E.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  Temperature-humidity index (THI) values applicable to South Africa and Namibia have been established during this investigation for each month of the year by means of computerized modelling and mapping techniques. The data ...
• Identification of the antigenic proteins of Cowdria ruminantium 

  Neitz, Albert Walter Herman; Rossouw, Mirinda; De Waal, D.T.; Du Plessis, J.L.; Van Gas, Letitia; Brett, Susan; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  Immunoblotting of Cowdria ruminantium proteins with sheep or bovine antiserum identified 2 antigenically conserved proteins, one being an immunodominant 31 kDa and the other a minor 27 kDa protein. These proteins are present ...
• Failure of an Actinomyces pyogenes vaccine to protect sheep against an intravenous challenge 

  Hunter, Pamela; Van der Lugt, Jaco J.; Gouws, J.J.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  The immunity conferred by an A. pyogenes bacterin-toxoid was evaluated in sheep, using an intravenous challenge system. Three sheep were vaccinated and 3 served as controls. The vaccinated sheep were not protected against ...
• Subject index 

  Unknown; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)
• On sampling tick populations : the problem of overdispersion 

  Petney, T.N.; Van Ark, H.; Spickett, Arthur M.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  Data collected on both free-living and parasitic tick populations are likely to be overdispersed. The use of means from few replicate samples of overdispersed data as quantitative estimators of tick population density is ...
• An attempt to improve the immunization of sheep against heartwater by using different combinations of 3 stocks of Cowdria ruminantium 

  Du Plessis, J.L.; Potgieter, F.T.; Van Gas, L.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  Neither sheep immune to the Ball 3, the Kwanyanga or the Mara stocks of Cowdria ruminantium nor those immunized with combinations of these 3 stocks were protected against challenge with the Mali stock. Against challenge ...
• The freeze-drying of Cowdria ruminantium 

  Du Plessis, J.L.; Van Gas, L.; Labuschagne, F.J.; Wijma, S.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  Lyophilized tissues of mice and blood of sheep, infected with either the Kumm, the Welgevonden or the Ball 3 stock of Cowdria ruminantium, remain infective to mice and sheep after storage at 4ºC for 90 days. Freeze-dried ...
• Host cellular components adhering to the tegument of schistosomes from cattle, buffalo, hippopotamus and lechwe 

  Kruger, F.J.; Wolmarans, C.T.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  The teguments of adult Schistosoma mattheei from cattle and buffalo, S. hippopotami from hippopotamus and S. margrebowiei from lechwe were examined by means of scanning electron microscopy for cells possibly engaged in ...
• The isolation and serology of Brucella melitensis in a flock of goats in central RSA 

  Ribeiro, L.M.M.; Herr, S.; Chaparro, F.; Van der Vyver, F.H.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  Brucella melitensis biotype 1 was isolated in pure culture from the lungs, liver, spleen, kidney, stomach contents, abomasum and brain of an aborted caprine (Boer goat) foetus in the district of Cullinan, near Pretoria. ...
• Effects of microclimatic variables on the availability and movement of third-stage larvae of Ostertagia ostertagi on herbage 

  Krecek, R.C.; Murrell, K.D.; Douglass, L.W.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  Assessments were made of the influence of several microclimatic variables on the availability of third-stage larvae of Ostertagia ostertagi, on pasture herbage. Variables most closely related to recovery of larvae from the ...
• A field strain of Trichostrongylus colubriformis resistant to levamisole and morantel in South Africa 

  Van Wyk, Jan Aucamp; Bath, Gareth F.; Gerber, H.M.; Alves, Regina M.R.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  A strain of Trichostrongylus colubriformis from Nottingham Road, in Natal, was found to be solidly resistant to levamisole and morantel at the recommended dose levels. Untreated control sheep in fact harboured fewer worms ...
• The use of sensitivity discs in the identification of Campylobacter species 

  Ribeiro, L.M.M.; Herr, S.; Pefanis, S.M.; Gous, A.G.S.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  Filter paper discs were impregnated with a solution containing 20 mg of triphenyltetrazolium chloride per millilitre, and used in the typing of catalase-positive Campylobacter species. Also used were filter paper discs ...
• Feeding habits and flight-range of blow-flies (Chrysomyia spp.) in relation to anthrax transmission in the Kruger National Park, South Afnca 

  Braack, L.E.O.; De Vos, Valerius; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  Carrion-frequenting blow-flies (Chrysomyia albiceps and C. marginalis) were allowed 4 days of feeding on ³²P-orthophosphate-labelled blood or an Impala carcass (Aepyceros melampus) in the northern Kruger National Park, ...
• Concurrent babesiosis and ehrlichiosis in the dog : blood smear examination supplemented by the indirect fluorescent antibody test, using Cowdria ruminantium as antigen 

  Du Plessis, J.L.; Fourie, Niel; Nel, P.W.; Evezard, D.N.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  Giemsa-stained, peripheral blood smears of 67 dogs, showing clinical signs typical of babesiosis or reminiscent of concurrent babesiosis and ehrlichiosis, were examined for the presence of Babesia canis and Ehrlichia canis. ...
• Heat stress in dairy cattle under southern African conditions. II. Identification of areas of potential heat stress during summer by means of observed true and predicted temperature-humidity index values 

  Du Preez, J.H.; Giesecke, W.H.; Hattingh, P.J.; Eisenberg, B.E.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  November-March are the hottest months of the year with the highest monthly mean "temperature-humidity index" (THI) in South Africa and Namibia. These 5 months are associated with severe heat stress in dairy cattle, are of ...
• The use of filter paper discs impregnated with thionin acetate, basic fuchsin and thionin blue in the identification of Brucella species 

  Ribeiro, L.M.M.; Herr, S.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  Filter paper discs impregnated with solutions containing 0,25, 0,5 and 1 mg/ml of thionin acetate, 0,75 and 1,5 mg/ml of basic fuchsin and 0,5 mg/ml of thionin blue were used in the typing of Brucella species. All the ...
• An experimental Schistosoma mattheei infection in man 

  Wolmarans, C.T.; De Kock, K.N.; Van der Walt, M.P.K.; Verwoerd, Daniel Wynand (Published by the Government Printer, Pretoria., 1990)

  Certain aspects of the immune response of a male experimentally infected with 3-day old cercariae of a pure field strain of Schistosoma mattheei were investigated. Among others, aspects such as the reaction of eosinophils, ...

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