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European Journal of Forest Research -  相似文献   
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OBJECTIVE: To assess a ready-to-use formulation of dicyclanil to prevent blowfly strike on coarse and fine woolled sheep under New Zealand conditions. DESIGN: Randomized clinical field trials. PROCEDURE: In a first field trial, coarse wooled sheep treated with a ready-to-use, 5% dicyclanil formulation were compared with untreated control sheep for up to 21 weeks. In a second field trial, fine woolled sheep, treated with the same dicyclanil formulation, were compared with untreated sheep for up to 19 weeks. Efficacy was assessed by calculating the aggregated cumulative strike rate. RESULTS: For trial 1 (coarse woolled sheep) the aggregated cumulative strike rate at the end of the trial at week 21 after treatment reached 3.9% and 19.1% for treated and untreated sheep, respectively. For the treated animals the aggregated cumulative strike rate reached the 1% and 2% benchmarks between weeks 11 and 12. For trial 2 (fine woolled sheep) the aggregated cumulative strike rate at the end of the trial at week 19 reached 0.6% and 7.5% for treated and untreated sheep, respectively. Wool length at the time of application did not substantially influence the efficacy of dicyclanil. CONCLUSION: Under New Zealand field conditions, a ready-to-use 5% spray-on formulation of dicyclanil protected coarse woolled sheep for at least 12 weeks and fine woolled sheep for at least 19 weeks.  相似文献   
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For investigations of CO2-stunning of feeder- and slaughter-pigs parameters of behaviour, blood-gas-analyses and electroencephalograms were chosen. The following results were obtained: 1. Blood-gas-analyses proved that the CO2-stunning does not produce unconsciousness due to a lack of oxygen. 2. The criterias of general anaesthesia: unconsciousness, muscle-relaxation and analgesia with total reversibility could be confirmed. 3. The violent convulsive symptoms were evaluated as reactions identical with the stage II of GUEDEL's scheme of anaesthesia. 4. Muscular agitation, which sometimes appeared a few seconds before the stage of excitation, was judged to belong either to the start of the excitation phase or to the end of Guedel's stage of analgesia, during which the sensitivity is decreased. Neither study of behavior nor objective measurements showed, during the first 10 to 20 seconds of exposure to the CO2, any sign of pain or suffering related to the Act for Prevention of Cruelty to Animals, and accordingly such suffering should not be ascribed to the CO2 stunning method.  相似文献   
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Summary A review is given about publications of the last 30 years, concerning problems of high nitrate content of feeds. Nearly 10 areas of scientific work can be discerned. The most important of them have to do with: Analysis of nitrate and nitrite; danger of poisoning by feeds and water rich in nitrate; physiological and pathological consequences of high doses of nitrate or nitrite; reduction of nitrate (in the rumen and in the fermentation of plants) to nitrite, hydroxylamine and ammonia; behaviour of nitrate in the process of silage making; adverse effects upon the functions of the thyroid gland by nitrite and the disturbances of the availability of vitamin A and vitamin E by nitrate-nitrite.
Résumé On a donné un rapport sur les travaux scientifiques publiés dans les dernières trente années, concernant les problèmes d'une teneur haute en nitrate dans les fourrages. On peut discerner à peu près dix régions de travail scientifique. Les plus importantes sont: analyses du nitrate et du nitrite; le danger des intoxications par les fourrages et par l'eau, qui sont riches de nitrate; les conséquences physiologiques et pathologiques des doses hautes du nitrate ou du nitrite; la réduction du nitrate (dans le panse des ruminants et dans les fourrages en fermentation) au nitrite, au hydroxylamine et à l'ammonique; les réactions du nitrate pendant la préparation des silages; les influences défavorables aux fonctions de la glande thyroide par le nitrite; et les actions de déranger l'utilisation de la vitamine A et de la vitamine E par nitrate-nitrite.
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The bovine neutrophil: Structure and function in blood and milk   总被引:1,自引:0,他引:1  
Migration of polymorphonuclear neutrophil leukocytes (PMN) into the mammary gland provide the first line of defense against invading mastitis pathogens. Bacteria release potent toxins that activate white blood cells and epithelial cells in the mammary gland to secrete cytokines that recruit PMN that function as phagocytes at the site of infection. While freshly migrated PMN are active phagocytes, continued exposure of PMN to inhibitory factors in milk such as fat globules and casein, leads to altered PMN morphology and reduced phagocytosis. In the course of phagocytosing and destroying invading pathogens, PMN release chemicals that not only kill the pathogens but that also cause injury to the delicate lining of the mammary gland. This will result in permanent scarring and reduced numbers of milk secretory cells. The life span of PMN is limited by the onset of apoptosis. To minimize damage to mammary tissue, PMN undergo a specialized process of programmed cell death known as apoptosis. Macrophages quickly engulf and phagocytose apoptotic PMN, thereby minimizing the release of PMN granular contents that are damaging to tissue. The PMN possess an array of cell surface receptors that allow them to adhere and migrate through endothelium and to recognize and phagocytose bacteria. One receptor found on phagocytes that is receiving considerable attention in the control of infections by Gram-negative bacteria is CD14. Binding of lipopolysaccharide (LPS) to membrane bound CD14 causes release of tumor necrosis factor-alpha and sepsis. Binding of LPS to soluble CD14 shed from CD14-bearing cells results in neutralization of LPS and rapid recruitment of PMN to the site of infection. Recent advances in the fields of genomics and proteomics should greatly enhance our understanding of the PMN role in controlling intramammary infections in ruminants. Further, manipulation of PMN, through either recombinant proteins such as soluble CD14 that enhance PMN response or agents that mediate PMN apoptosis, may serve as novel therapeutics for the treatment of mastitis.  相似文献   
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