Parasitism and host–plant relationships in the dipterous stem borer complex of ryegrass     

James Howell 《Pest management science》1982,13(4):367-372

Samples taken from a ryegrass variety trial at the Grassland Research Institute, Hurley, and examined at the Welsh Plant Breeding Station, showed that the dominant stem borer species in the overwintering generation were Geomyza tripunctata Fall. and Oscinella frit L. The rate of parasitisation of stem borers, largely by species of Hymenoptera, ranged from 15 to 43%. There were differences in host plant selection by Geomyza compared with Oscinella spp. The numbers of both stem borer groups were significantly associated with the total number of tillers per sample; however, this relationship was found to differ markedly between varieties.  相似文献   

The occurrence of serotype 4 of avian influenza A virus in Canadian poultry.   总被引：1，自引：1，他引：0       下载免费PDF全文

G Lang  J Howell    A E Ferguson 《The Canadian veterinary journal. La revue veterinaire canadienne》1972,13(1):17-20

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ARTHROGRYPOSIS: AN INHERITED DEFECT IN NEWBORN CALVES     

P. S. Nawrot †  W. E. Howell  H. W. Leipold‡ 《Australian veterinary journal》1980,56(8):359-364

Arthrogryposis, frequently associated with cleft palate, scoliosis and kyphosis, has been investigated in pure and crossbred Charolais calves. During a 3-year study, a total of 76 congenitally malformed arthrogrypotic calves from 41 purebred and commercial Charolais herds was investigated. Investigations of the management, feeds, water and poisonous pasture plants in 6 herds reporting deformed calves did not reveal any factors which could be associated with the appearance of the defect. Analysis of pedigrees and matings which produced arthrogrypotic calves revealed that the arthrogryposis syndrome in the Charolais breed and its crosses in Canada is genetic in origin and caused by an autosomal recessive gene with complete penetrance in the homozygous state.  相似文献   

SUDDEN DEATH IN PUPPIES ASSOCIATED WITH A SUSPECTED VIRAL MYOCARDITIS     

C R Huxtable  J M Howell  W R Robinson  G E Wilcox  D A Pass 《Australian veterinary journal》1979,55(1):37-38

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The use of historical information for selecting a sample from a population of lakes     

A. H. El-Shaarawi  S. R. Esterby  G. Howell 《Water, air, and soil pollution》1989,46(1-4):305-316

In planning a monitoring strategy to quantify the present chemical status of a population of lakes in regions susceptible to the effects of acidic deposition, a decision must be made regarding the number and locations of the lakes to be monitored. Statistical methods provide the bases for making a satisfactory decision by utilizing historical information available about the characteristics of the population of lakes. We present the statistical issues involved in making the decision and present examples using LRTAP data from Quebec.  相似文献   

The effect of copper and heliotrope on the composition of bile in sheep     

H.S. Deol  J.McC. Howell  P.R. Dorling  H.W. Symonds 《Research in veterinary science》1992,53(3):324-330

The effects of interrupting the enterohepatic circulation (EHC) of bile salts for seven hours and of feeding copper and heliotrope alone and combined for 13 weeks, on bile flow and excretion of copper, zinc, iron and alpha-mannosidase were studied in sheep. Interruption of EHC reduced bile flow rate and increased the concentration of copper, zinc, iron and bile acids while alpha-mannosidase's activity remained stable. Changes in concentration were related to changes in bile volume for copper and zinc only. Total output per hour was not changed. Biliary concentration of copper correlated with alpha-mannosidase's activity in control sheep and those given copper or heliotrope, supporting the hypothesis that lysosomes are involved in biliary secretion of copper in sheep. Increasing the intake of copper increased the rate of excretion of copper in bile. Copper output was lower when heliotrope was fed alone.  相似文献   

Effects of intravenously administered tetra-thiomolybdate on the distribution of copper in the liver and kidney of copper loaded sheep: a histochemical study     

J S Kumaratilake  J M Howell 《Research in veterinary science》1987,42(2):154-161

The effects of intravenously administered thiomolybdate on the liver and kidney of copper loaded sheep were studied using 16 ewes in three groups. Copper, iron and molybdenum concentrations were determined by spectrophotometry and the distribution of copper in the liver and kidney was studied histochemically. Following thiomolybdate administration, the concentration of copper in the liver was reduced, that of molybdenum increased and the concentration of copper and molybdenum in the kidney increased. The reduction of copper concentration in the liver was associated with reductions in the number and size of granules in hepatocytes which stained positively for copper and in the number of Kupffer cells containing positively staining granules. The decrease in the amount of copper in hepatocytes appeared to be greater than that in Kupffer cells. This effect was greatest in the centrilobular zones and least in the periportal zones. The increased concentration of copper and molybdenum in kidney was associated with an increase in the number and size of granules staining positively for copper in the epithelial cells of the proximal convoluted tubules which suggested an uptake of copper-molybdenum complexes by the lysosomes of these cells.  相似文献   

Experimental chronic copper toxicity in sheep. Biochemical and haematological studies during the development of lesions in the liver   总被引：1，自引：0，他引：1  

J Ishmael  C Gopinath  J M Howell 《Research in veterinary science》1972,13(1):22-29

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Developments in veterinary science. The veterinary school at the close of the second millennium.          下载免费PDF全文

D G Howell 《The Canadian veterinary journal. La revue veterinaire canadienne》1969,10(6):153-158

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Case report. Adactyly in a grade beef Shorthorn herd.          下载免费PDF全文

H W Leipold  W F Cates    W E Howell 《The Canadian veterinary journal. La revue veterinaire canadienne》1970,11(12):258-260

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