Over a two month period, 148 dogs presented for surgery had general anaesthesia induced and sometimes maintained with propofol. Excitatory phenomena were recorded on 12 occasions. Signs included muscle twitching, opisthotonus and limb hyperextension (nine cases), and panting with associated activity of the brachiocephalicus muscle and tongue retraction (three cases). The records for a similar two month period were examined for data and observations relating to thiopentone. During this period anaesthesia was induced with thiopentone in 71 dogs and no excitatory phenomena were recorded. 相似文献
1. Studies on the survival of Salmonella enteritidis in poultry units and food were carried out over a two‐year period.
2. The organism persisted for at least one year in an empty trial house at the laboratory in which naturally‐infected broiler breeder birds had previously been housed. A similar survival period was seen in a building which had housed an infected layer breeder flock, although infection was not detected in a subsequent pullet flock.
3. Salmonella enteritidis was also frequently found surviving outside poultry houses in small pockets of litter and fan dust which had been left after cleansing and disinfection of the site. On some poultry units S. enteritidis was also found in wild bird droppings.
4. Salmonella contamination appeared to persist preferentially in association with dust particles swept from the floor and in food troughs and S. enteritidis survived at least 26 months in artificially contaminated poultry food. 相似文献
Light microscope observations on oat cells in the ovine pneumonia-pleurisy complex are presented. This study is based on the experimental production of the disease by viruses and Pasteurella haemolytica. Oat cells appeared only in necrotic lesions associated with large numbers of P. haemolytica in the pneumonic lung. It is suggested that oat cells originate from blood monocytes, which transform into the oat shape when developing in the necrotic, hypoxic environment created by P. haemolytica. They were not, however, observed to be phagocytic. Oat cells are characteristic of pneumonic pasteurellosis but are not pathognomonic because they can also be found in extrapulmonary locations and in other pathological conditions of the lungs. 相似文献
This paper describes experiments carried out with different depths of topsoil and methods of cultivation on an ash lagoon at Besthorpe, near Newark. Good yields of grass were obtained even on bare ash with suitable rates of fertilizer application. In the conditions existing at Besthorpe, the optimum depth of soil appeared to be three in. (7.62 cm), but the depth of cultivation (three in. (7.62 cm) or twelve in. (30.48 cm), die latter resulting in mixtures of soil and ash, had no significant effect. B uptake by the growing plants was markedly lower in the third year of the experiment but, apart from its possible effect on yield, it produced no ill effects. 相似文献
Thirty-four introductions of Lotus corniculatus and L. uliginosus , obtained from Europe, North America and New Zealand, were grown in plots with Aberystwyth S23 ryegrass at three centres in Wales (230–400 m a. s. 1.) to assess their potential as legumes for poor acid hill soils. The control white clover varieties were generally successful in these difficult conditions, whereas all the Lotus introductions were poor in two experiments and in the third experiment gave way to volunteer white clover by the third harvest year. These results indicate that none of the numerous Lotus varieties tested would be a useful addition to pasture seeds mixtures for hill lands in Wales. 相似文献
The mean yields of 4 varieties of lucerne were compared under 5 methods of growing: broadcast with and without grass; drills 2 ft apart; alternate lucerne/grass drills 1 ft apart; spaced plants. One cut was harvested in the sowing year and 3 cuts a year for the next 3 years. The alternate lucerne/grass drills yielded 20% less dry matter than the comparable broadcast plots. Broadcasting and sowing in alternate drills had the same effect on the pattern of lucerne/grass competition. The meadow fescue companion produced its highest yield at the first cut and there was a marked drop during each year and from year to year. There was little evidence of nitrogen transfer from the lucerne to the grass. 相似文献
Complete assessment of vertebral trauma in dogs currently requires CT and MRI for evaluation of the osseous and soft tissue structures that contribute to vertebral stability. Some studies in people have suggested that MRI may be sensitive and specific at detecting vertebral fractures making this potentially a single modality that could be used in spinal trauma evaluation. This study aimed to assess the ability for observers to evaluate vertebral fractures using MRI when compared to CT, which was used as the reference standard. Twenty‐nine dogs with previously diagnosed acute vertebral fractures and four dogs with no vertebral fracture that had undergone sequential CT and MRI were included into the study. One hundred twenty‐eight vertebrae were evaluated for the presence of fractures. Imaging studies were read by two observers blinded to the history. While both observers had similarly high sensitivity and specificity for simple detection of any fractured vertebrae, interobserver agreement was only moderate (κ = 0.584). When evaluations were specifically limited to detection of structurally unstable fractured vertebrae both observers showed improved specificity and interobserver agreement became substantial (κ = 0.650). Complete agreement for exact fracture location between MRI and CT results was only achieved in 14.3‐32.6% of fractured vertebra with up to 79% of fractures being missed in some vertebral structures. This suggests that although MRI may be able to detect the presence of fractured vertebrae, it is not able to replace CT for the complete evaluation of the traumatized spine and documentation of fracture morphology. 相似文献
Plasticity in life‐history traits provides advantages for introduced fish in overcoming demographic bottlenecks that would otherwise inhibit establishment. Here, the influence of population density, temperature and latitude was tested on the growth increments and growth rates of invasive populations of topmouth gudgeon Pseudorasbora parva, a small Asian cyprinid fish that is invasive across Europe. Aquaria experiments tested the roles of fish number and temperature on growth increments under a fixed food supply, pond experiments tested the role of density on growth increments, and a field study completed in England and Wales tested the influence of density and latitude on growth rates. In aquaria experiments, whilst growth increments were higher at 21 and 23 °C than at 19 and 25 °C, fish number had a greater influence on growth than temperature. Higher growth increments were produced at lower densities. In experimental ponds, growth increments were significantly higher in ponds with low densities of P. parva compared with those at elevated densities. In the field study comprising 10 wild populations across a latitudinal gradient of 4.0°N, a difference in mean air temperatures of approximately 3 °C, and estimated densities between 0.5 and 65.0 m?2, population density was the only significant predictor of growth rates. Whilst populations at very low densities comprised of significantly faster growing individuals, there were no significant differences when densities were between 15 and 65 m?2. Thus, invasive P. parva populations have considerable growth plasticity, especially at low densities, with this likely to be important in their ability to colonise new environments. 相似文献