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11.
This report is concerned with a consistent problem of neonatal calf diarrhea (NCD) in a dairy herd in which, for nearly two years, the morbidity had approached 100% and the mortality had varied from 20% to 45%. Generally, diarrhea appeared at three days of age. By the fluorescent antibody tissue section technique the two Nebraska NCD viruses (reo-like and corona-like) were detected in the cytoplasm of many absorptive cells of the small intestine from a calf submitted for necropsy. Reo-like virus antigen was not detected in the absorptive and crypt cells of the colon but coronavirus-like antigen was. An adenovirus was also isolated from the small intestine of this calf. The disease was reproduced experimentally in a two day old colostrum deprived calf with a bacteria free intestinal homogenate obtained from the naturally infected calf. Both Nebraska NCD viruses were demonstrated in this experimental animal. However, the adenovirus was not re-isolated. Histological lesions observed in the small and large intestines of the naturally and experimentally infected calves were similar and because of their good correlation with the immunofluorescent findings, a combination of the two Nebraska NCD viruses was thought to be a major cause of the neonatal calf diarrhea problem afflicting this dairy herd. 相似文献
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Shear properties of clear softwood from Norway spruce were investigated by means of the Arcan shear test. The test enabled fairly detailed measurements of pure shear until failure in each of the three orthotropic shear planes, where video extensometry was used for strain measurements. A total number of 85 specimens were tested in 6 different configurations. A varying degree of nonlinearity was observed between the different configurations and material planes, especially for rolling shear. The stress–strain curves were adapted with linear, bilinear and Voce models. Compared to the linearized variant, it was found that the bilinear model generally increases the model accuracy by a factor of approximately two, whereas the Voce model showed even higher accuracy, although its adaptive robustness was somewhat lower. The parameters demonstrated low correlations to density, whereas the correlations with the initial shear moduli in many cases were considerably higher and significant. The correspondence with similar values reported in literature was found to be fairly good. 相似文献
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Isolement du virus de la rhino-trachéite infectieuse bovine à partir du liquide synovial du tarse d''un taureau 
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下载免费PDF全文 P. Lamothe Y. Larouche G. Marsolais C. Montpetit L. Breton R. Malo H. Saint-Pierre 《The Canadian veterinary journal. La revue veterinaire canadienne》1979,20(9):237-241
Isolation of infectious bovine rhinotracheitis virus from the tarsal joint of a bullInfectious bovine rhinotracheitis virus was isolated from the right tarsal joint of a bull who was showing signs of a systemic viral infection. The clinical signs manifested by 16 bulls of this herd are described, the laboratory methods used are listed and the results are analysed and discussed. 相似文献
14.
Male fertility and sex ratio at birth in red deer 总被引：1，自引：0，他引：1
Gomendio M Malo AF Soler AJ Fernández-Santos MR Esteso MC García AJ Roldan ER Garde J 《Science (New York, N.Y.)》2006,314(5804):1445-1447
Efforts to test sex ratio theory have focused mostly on females. However, when males possess traits that could enhance the reproductive success of sons, males would also benefit from the manipulation of the offspring sex ratio. We tested the prediction that more-fertile red deer males produce more sons. Our findings reveal that male fertility is positively related to the proportion of male offspring. We also show that there is a positive correlation between the percentage of morphologically normal spermatozoa (a main determinant of male fertility) and the proportion of male offspring. Thus, males may contribute significantly to biases in sex ratio at birth among mammals, creating the potential for conflicts of interest between males and females. 相似文献
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S.K. Papiernik M.J. Lindstrom T.E. Schumacher J.A. Schumacher D.D. Malo D.A. Lobb 《Soil & Tillage Research》2007,93(2):335-345
Soil movement by tillage redistributes soil within the profile and throughout the landscape, resulting in soil removal from convex slope positions and soil accumulation in concave slope positions. Previous investigations of the spatial variability in surface soil properties and crop yield in a glacial till landscape in west central Minnesota indicated that wheat (Triticum aestivum) yields were decreased in upper hillslope positions affected by high soil erosion loss. In the present study, soil cores were collected and characterized to indicate the effects of long-term intensive tillage on soil properties as a function of depth and tillage erosion. This study provides quantitative measures of the chemical and physical properties of soil profiles in a landscape subject to prolonged tillage erosion, and compares the properties of soil profiles in areas of differing rates of tillage erosion and an uncultivated hillslope. These comparisons emphasize the influence of soil translocation within the landscape by tillage on soil profile characteristics. Soil profiles in areas subject to soil loss by tillage erosion >20 Mg ha−1 year−1 were characterized by truncated profiles, a shallow depth to the C horizon (mean upper boundary 75 cm from the soil surface), a calcic subsoil and a tilled layer containing 19 g kg−1 of inorganic carbon. In contrast, profiles in areas of soil accumulation by tillage >10 Mg ha−1 year−1 exhibited thick sola with low inorganic carbon content (mean 3 g kg−1) and a large depth to the C horizon (usually >1.5 m below the soil surface). When compared to areas of soil accumulation, organic carbon, total nitrogen and Olsen-extractable phosphorus contents measured lower, whereas inorganic carbon content, pH and soil strength measured higher throughout the profile in eroded landscape positions because of the reduced soil organic matter content and the influence of calcic subsoil material. The mean surface soil organic carbon and total nitrogen contents in cultivated areas (regardless of erosion status) were less than half that measured in an uncultivated area, indicating that intensive tillage and cropping has significantly depleted the surface soil organic matter in this landscape. Prolonged intensive tillage and cropping at this site has effectively removed at least 20 cm of soil from the upper hillslope positions. 相似文献
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L. Ayalew J. L. Frchette R. Malo C. Beauregard 《Canadian journal of veterinary research》1973,37(4):356-361
Nematode populations is stabled ewes of the Rimouski region were studied by means of fecal worm egg counts, fecal culture of larvae, and worm counts at necropsy. It was found that during the winter strongyle egg counts were low, Trichostrongylus eggs being most numerous, The stronglye egg counts increased following lambing and reached peak in June. Ostertagia spp was the principal contributor to this “spring-rise”, with substantial contribution from Trichostrongylus and Haemonchus contortus. The bulk of adult worm populations in winter, however, was made up of Trichostrongylus, whereas the great majority of the populations of Ostertagia spp, H. contortus and Nematodirus spp were inhibited in development at the fourth larval stage. All the worms recovered at necropsy in spring were adults, coinciding with the “spring-rise”. 相似文献