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SUMMARY: During 1988, 2 farmers in the Bega district agisted pregnant cattle in the Hunter Valley of New South Wales. On return to the district to calve, 54% of calves from herd 1 and 30% of calves from herd 2 were affected with congenital arthrogryposls or hydranencephaly caused by Akabane virus infection. Field observations and laboratory findings from this outbreak are presented, illustrating the danger of moving immunologlcally naive animals into areas where Akabane virus is endemic. 相似文献
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Metabolism of 14C asulam applied with surfactant was studied in Senecio Jacobaea L. and Medicago saliva L. Plants were harvested 48, 96 and 144 h after treatment and extracted with acetone. The aqueous residue of the acetone extract was partitioned with ethyl acetate and the 14C activity in the ethyl-acetate phase, the aqueous phase and the plant residue was determined. A significant amount of 14C activity was not extracted by acetone from either species. This amount increased with time in M. sativa but remained relatively constant in S. jacobaea. More 14C activity was found in the aqueous phase than in the ethyl-acetate phase in M. sativa while the reverse was true in S. jacobaea. Significantly lower amounts of free asulam were identified in M. sativa than in S. jacnbaea. Still, results of these and previous studies on retention, uptake and translocation do not completely account for differences in sensitivity found in greenhouse and field applications. Other possible explanations for selectivity are discussed. 相似文献
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THE KINETICS OF STRAW DECOMPOSITION IN RELATION TO ITS POTENTIAL TO PRODUCE THE PHYTOTOXIN ACETIC ACID 总被引：4，自引：0，他引：4
The losses of total weight and of the individual components of oat straw were followed under field conditions over one cropping season. Decomposition rates of cellulose and hemicellulose were closely similar, and together these polysaccharides accounted for most of the weight losses. Losses of lignin were small, and total weight loss can be calculated from the increase in percentage lignin in recovered samples. Straw retained the potential to produce phytotoxic concentrations of acetic acid only during the early stages of decomposition. Both the water soluble components and the readily available polysaccharides are probably substrates for the production of acetic acid. Early incorporation of straw minimised the potential for toxin production during winter. 相似文献
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TISHA A. M. HARPER JERYL C. JONES GEOFFREY K. SAUNDERS GREGORY B. DANIEL TANYA LEROITH ERIN ROSSMEISSL 《Veterinary radiology & ultrasound》2011,52(4):428-435
The sensitivity of low‐field magnetic resonance (MR) T2* images for predicting the presence of meniscal lesions was determined in 12 dogs with naturally‐occurring cranial cruciate ligament rupture and three control dogs, using histopathology as the reference standard. Previously published grading systems were used to grade the severity of meniscal lesions on MR images, gross inspection and histopathology. Focal areas of increased signal intensity were detected in 11/12 symptomatic dogs and 3/3 control dogs. Lesions mimicking meniscal tears (pseudotears) were identified at junctions between meniscal margins and adjacent connective tissue in control dogs and dogs with naturally occurring disease. Histopathologic lesions were present in all menisci of both symptomatic and control dogs, including the menisci from two affected dogs that appeared grossly normal but were removed and submitted based on MR imaging findings. Histopathologic lesions identified included hyaline cartilage metaplasia and changes in the amount of ground substance and cellularity. The sensitivity of MR imaging for detecting the presence of meniscal histopathologic lesions was 90% in symptomatic dogs and 91% in control dogs. However, agreement between severity scores for the different tests was poor. Low‐field MR imaging is a sensitive test for predicting the presence but not severity of meniscal histopathologic lesions in dogs with naturally‐occurring cranial cruciate ligament rupture. Findings also supported previous studies indicating that histopathologic lesions can be present in dogs with grossly normal menisci. An improved grading system for comparing MR images and histopathologic severity of meniscal lesions in dogs is needed. 相似文献
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R. C. HARPER 《The Journal of small animal practice》1987,28(6):543-547
The indications and contraindications for the use of chloramphenicol are reviewed and some suggestions made regarding the use of this drug in small animal practice. 相似文献
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J. W. PLANT S. T. LOMAS P. A. W. HARPER D. W. DUNCAN† S. N. CARROLL† 《Australian veterinary journal》1987,64(10):308-310
Hydrops foetalis was observed in foetuses from a sheep flock in southern New South Wales over 4 years. Ewes showed marked abdominal distension and most died at parturition, being unable to deliver large affected foetuses. These had birth weights up to 18 kg and exhibited severe generalised oedema of subcutaneous tissues, fluid accumulation in the serous cavities and oedema of the placenta. Microscopically, there was a generalised extramedullary haemopoiesis and massive oedema, consistent with a chronic foetal anaemia. No infectious or environmental factors could be incriminated in the outbreak. The clinical and pathological findings resemble those of the homozygous alpha-thalassaemia in infants associated with haemoglobin Bart's. 相似文献
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CONTROLLED INTERFERENCE WITH NATURAL POPULATIONS OF PLANTAGO LANCEOLATA, P. MAJOR AND P. MEDIA 总被引：1，自引：0，他引：1
Summary. An experiment was made to determine the effect of the removal of grasses on the behaviour of populations of Plantago lanceolata , P. media and P. major in three grassland habitats. Treatments included the addition of seed of all three species to the existing vegetation. The grasses were removed by treatment with 2,2-dichloropropionic acid (dalapon), a herbicide selective against the Gramineae. The chemical appears to be slightly toxic to the Plantago species at the dose used (12 Ib/ac a.e.). The removal of the grasses was followed by a marked increase in the plantain populations shown both in counts of the numbers of plants and seedlings and in increased seed output per unit area. Deliberate sowing of seed into the habitats in autumn resulted in increased numbers of seedlings in the following spring, particularly in those plots where the grasses had been removed. Species of Plantago not occurring naturally in the communities were frequently established by sowing seed, if the grasses had been removed, but not otherwise. The overall results of the experiment suggest that in two of the communities the grasses played an important role in determining the presence or absence of particular Plantagn species and also in controlling the size of the existing plantain populations. The experiment is discussed in the wider context of population control in plants.
Tentative de modification de populations naturelles de Plantago lanceolata, P. major et P. media. 相似文献
Tentative de modification de populations naturelles de Plantago lanceolata, P. major et P. media. 相似文献