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71.
CASE HISTORY: Twelve of 150 goat kids, 4–10 days old, died 3 days after disbudding with a hot iron. Another 18 kids had been ill the previous day but survived following antibiotic therapy. Five of the dead kids were necropsied.

PATHOLOGICAL FINDINGS: There was necrosis and haemorrhage of the skin, subcutaneous tissues and frontal bone at disbudding sites in all five kids examined post mortem. Beneath disbudding sites in 4/5 kids there were bilateral, dark red, often cavitated areas of necrosis extending deep into the frontal cortex of the brain. Histologically, these areas consisted of coagulation necrosis, haemorrhage, vascular thrombosis and suppurative inflammation. Numerous bacteria, predominantly large Grampositive rods, were present in the necrotic brain tissue. In the remaining kid, bilateral areas of yellow discolouration and flattening of gyri in frontal lobes corresponded histologically to extensive polioencephalomalacia. A mixed growth of aerobes and anaerobes was cultured from the brain of one kid with suppurative lesions.

CLINICAL RELEVANCE: Thermal disbudding of neonatal kids is widely practised in dairy goat herds and is considered the method of choice for disbudding in New Zealand. However, the skull of goat kids is much thinner than that of calves and the safety margin for thermal injury to the brain is markedly reduced. This report highlights the risks associated with the technique and its potential as a welfare issue.  相似文献   
72.
CASE HISTORY: Investigations were conducted to determine the cause of an acute, multi-farm outbreak of porcine respiratory disease that included diarrhoea and subsequent loss of body condition in affected pigs. A definition for post-weaning multisystemic wasting syndrome (PMWS) including both clinical and pathological features, previously developed for the pig industry in New Zealand, was applied to the current outbreak. In addition to self-reporting by owners of affected farms, local veterinarians, disease and epidemiology consultants, and animal health officials from the Ministry of Agriculture and Forestry (MAF) were involved in conducting farm visits and submission of diagnostic specimens.

CLINICAL FINDINGS AND DIAGNOSIS: Pathogens known to be endemic in the pig industry in New Zealand as well as likely exotic diseases were excluded as causative agents of the outbreak. Clinical signs including dyspnoea, diarrhoea, and rapid loss of body condition were consistent with the New Zealand case definition for PMWS. Interstitial pneumonia, pulmonary oedema, generalised lymph-node enlargement, and presence of porcine circovirus type 2 (PCV2) inclusion bodies were consistently identified in affected pigs. Classical swine fever virus (CSFv), Porcine reproductive and respiratory syndrome virus (PRRSv), and Influenza virus were ruled out, using molecular and traditional virological techniques. Spread of the disease between farms was hypothesised to be facilitated by locally migrating flocks of black-backed seagulls. The original source of the disease incursion was not identified.

DIAGNOSIS: Based on the consistent presence of circovirusassociated lesions in lymphoid tissues in combination with generalised enlargement of lymph nodes, histiocytic interstitial pneumonia, clinical wasting, and poor response to antibiotic therapy, a diagnosis of PMWS was made.

CLINICAL RELEVANCE: PMWS should be considered in the differential diagnoses of sudden onset of respiratory dyspnoea, diarrhoea, and rapid loss of body condition in young pigs in New Zealand pig herds.  相似文献   
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Irreversibility and uncertainty render the standard capital budgeting techniques such as net present value (NPV) analysis insufficient as a decision criterion. The standard NPV underestimates the value of the investment by not including the value of waiting for new information to reduce the uncertainty of the cashflows generated by the investment. An alternative to NPV analysis is real options. In this study, we apply real options analysis to an investment decision for a grain producer in Western Australia. The investment choice is to either purchase machinery suitable for undertaking controlled traffic precision agriculture or acquire a conventional system and reduce sowing time. The results of the analysis suggest that the required rates of return for the two investment alternatives need to be approximately 96–156% higher than the rates of return used in the standard NPV analysis. These higher rates of return are required to compensate for the uncertainty inherent in the cropping systems of the farm. Also, in most cases, even though the variable costs of operating the precision agriculture system were higher, due to smaller operating widths, the additional returns generated by managing zones individually outweighed these additional costs. Further analysis also shows that the relative size of management zones has a marked effect on the returns generated and that it is possible to increase returns by taking out marginally productive zones.  相似文献   
75.
Gold nanoelectrodes of varied size: transition to molecule-like charging   总被引:1,自引:0,他引:1  
A transition from metal-like double-layer capacitive charging to redox-like charging was observed in electrochemical ensemble Coulomb staircase experiments on solutions of gold nanoparticles of varied core size. The monodisperse gold nanoparticles are stabilized by short-chain alkanethiolate monolayers and have 8 to 38 kilodaltons core mass (1.1 to 1.9 nanometers in diameter). Larger cores display Coulomb staircase responses consistent with double-layer charging of metal-electrolyte interfaces, whereas smaller core nanoparticles exhibit redox chemical character, including a large central gap. The change in behavior is consistent with new near-infrared spectroscopic data showing an emerging gap between the highest occupied and lowest unoccupied orbitals of 0.4 to 0.9 electron volt.  相似文献   
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78.
基于RS和GIS的柘皋河流域景观空间格局研究   总被引:2,自引:2,他引:0  
在RS和GIS技术的支持下,运用景观生态学原理,以2000年LandsatTM 7遥感数据为数据源,通过影像解译和实地调查获得柘皋河流域景观类型图,并采用景观指数分析法对流域内景观空间格局做定量分析,为流域内生态保护和区域经济的可持续发展提供有益参考。结果显示:柘皋河流域是以农业为主的发展模式。景观异质性高,分布相对均匀;耕地破碎化程度低,连通性好,利于农业发展;居民点与交通用地破碎化程度高,边缘效应强,对周围影响大。A区农业化和非农化矛盾最强烈。B区景观异质性高,景观类型分布均匀,生态结构稳定。C区景观异质性低,生态稳定性较差。  相似文献   
79.
Objective To compare serum and skin surface IgA concentrations from atopic and normal dogs.
Procedure IgA concentrations in sera and skin washings of 20 clinically normal dogs that had no history of pruritus or skin disease were compared to those obtained in 20 dogs with a diagnosis of atopy determined by history, clinical examination and positive intradermal skin test.
Results There was no significant difference in the mean serum IgA concentration in normal dogs (252 ± 187 mg/L) versus atopic animals (314 ± 327). When skin washings from all sites in both groups were compared, atopic dogs had significantly greater concentrations of IgA in their skin washings than normal dogs as evaluated by an enzyme-linked immunoassay (P < 0.001). However, there was no significant difference between the individual sites of the skin washings of atopic and normal dogs.
Conclusion IgA concentrations of skin washings in atopic dogs were greater than in normal dogs. Further investigations need to determine if the greater concentrations were caused by nonspecific inflammation or by secretion of allergen-specific IgA onto the skin surface.  相似文献   
80.
Ear tags impregnated with 20% diazinon were evaluated for their efficacy against the buffalo fly (Haematobia irritans exigua) on beef cattle in southern Queensland. Buffalo fly numbers and weight changes were recorded and diazinon residues in tissues of beef cattle and milk from lactating dairy cattle were assayed at different time intervals after tagging. In 2 efficacy trials conducted over 19 and 20 weeks, the mean numbers of buffalo fly on cattle each fitted with ear tags were 1 to 9 and 0 to 16, respectively, in trials 1 and 2, compared with 44 to 345 and 26 to 306 per head on untreated herds, respectively, despite regular spraying of the untreated herd in trial 1 with cyper-methrin to reduce fly burdens. Percentage buffalo fly control was 96.7 to 99.5% and 89.3 to 100% in the 2 trials. Cattle fitted with ear tags gained an average of 94 kg body weight after 5 months compared with 61 kg in the untreated herd, a net increase of 60% in treated animals compared with 28% in the untreated herd. Mean diazinon residue concentrations in the fat of perianal tissue biopsies were 0.02 to 0.03 mg/kg 1 to 8 weeks after tagging. Mean diazinon residue concentrations in the butterfat of milk from lactating dairy cattle were 0.01 to 0.04 mg/kg after tagging.  相似文献   
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