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I.J. Cunningham 《New Zealand veterinary journal》2013,61(1):9-16
Extract Under the grassland farming regime in New Zealand, copper deficiency in cattle and sheep can be effectively controlled by topdressing all the pastures on the farm each year with 5 pounds of copper sulphate per acre. Such treatment removes the deficiency by increasing the copper content of the herbage to a level that is adequate for grazing animals. 相似文献
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MC Barron RP Pech J Whitford IJ Yockney GW de Lisle G Nugent 《New Zealand veterinary journal》2013,61(5):209-217
Abstract AIM: To determine, for a variety of environmental conditions, how long Mycobacterium bovis might remain viable inside the carcass of a brushtail possum (Trichosurus vulpecula) that died of bovine tuberculosis (Tb), and to measure the rate of contact between free-ranging possums and possum carcasses. METHODS: Lesions of M. bovis were simulated by inoculating excised spleens weighing 0.5–1 g with 0.2 mL liquid culture containing approximately 5 x 107 cfu M. bovis/mL. Simulated lesions were inserted into possum carcasses (n=48) at the peripheral lymph nodes. Carcasses were placed in the field at two sites (a tussock grassland and a podocarp-broadleaved forest site) and in two seasons (summer and winter) for up to 62 days. Survival rates of M. bovis were estimated by sampling the simulated lesions over time, and culturing the recovered lesion to determine if any viable M. bovis bacteria were present. The time taken for a free-ranging possum to first encounter a dead possum in its home range was estimated by live-trapping possums and fitting them with proximity loggers (n=13). A ‘contact’ was recorded if these possums came within 40–50 cm of proximity loggers fitted to possum carcasses. RESULTS: There were strong seasonal and site effects in the survival rate of M. bovis in possum carcasses. In the grassland habitat, no viable bacilli were cultured from any carcass after 3 days in summer, whereas in winter all samples were culture-positive for the first 20 days, and some were still positive after 27 days. The survival rates for forest habitat were intermediate between the results for grassland, and there were no culture-positive carcasses after 9 days in summer or 27 days in winter. In summer, infected carcasses (n=6) were first encountered by possums a mean 1.9 (range 0.4–6.7) days after placement. CONCLUSIONS: Possum carcasses were contacted by free-ranging possums within the period that viable M. bovis were shown to survive in a carcass. The risk of such infection is likely to be most significant in winter or in areas with microhabitats where the survival of M. bovis is high. However, the generally low survival rate of M. bovis in possum carcasses and the low frequency of possum-to-carcass contacts indicate this route of transmission alone could not maintain Tb in a possum population. 相似文献
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AIM: To determine the prevalence of Mycobacterium bovis infection in brushtail possums (Trichosurus vulpecula) that did not have macroscopic lesions of bovine tuberculosis, and to evaluate culture of pooled tissues from multiple possums as a method for determining the M. bovis-infection status of wildlife populations in New Zealand. METHODS: Pools of selected tissues were collected from possums from four different populations known to be infected with M. bovis. Tissue pools from individual animals, and combined pools from multiple animals, were cultured for M. bovis. RESULTS: In the four populations investigated, the prevalence of possums with macroscopic lesions confirmed by culture to be infected with M. bovis ranged from 1 to 19 (mean 31/283; 10.9)%. The prevalence of possums with non-visible lesions that were culture positive for M. bovis in the same populations ranged from 4 to 10 (mean 24/283; 8.5)%. The mean of the log10 cfu of M. bovis of the macroscopic lesions and of the culture-positive samples that did not have visible lesions was 3.85 (SE 0.26) and 1.46 (SE 0.26) log10 cfu, respectively (p<0.01). Mycobacterium bovis was cultured from pools of 30–50 animals in the four populations studied. CONCLUSIONS: The finding of M. bovis infection in possums with non-visible lesions identified a potential deficiency of declaring possum populations free of M. bovis on the basis of absence of macroscopic lesions. The culturing of pools of selected tissues from multiple animals without visible lesions can be used to reduce laboratory costs of possum surveys without a major reduction in the ability to detect M. bovis infection. 相似文献
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Extract It has long been established that rats can play an important part in the transference of infectious diseases to man. With this fact in mind, the late Dr J. H. Blakelock, former Director of the National Health Institute, Wellington, began a survey of the rat population in the Wellington district and of rats brought to the area by overseas ships. This work has been continued, the trapped rats being examined for the presence of Xenopsylla cheopis, a flea known to be the chief vector of plague, for Pasteurella pestis, the causative organism of plague, for organisms of the Salmonella group, and for evidence of leptospiral infection. 相似文献
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AIM: To identify and purify secretory immunoglobulin A (sIgA), a key effecter molecule in mucosal immune responses, from milk of the brushtail possum (Trichosurus vulpecula). METHODS: Milk samples were collected from female possums with pouch young, and clarified by centrifugation and precipitation methods. The clarified fraction was purified by gel filtration and affinity chromatography to yield sIgA. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting techniques were used to assess the purity of the final product, and to identify the heavy (H) chain, light (L) chain and secretory component (SC) of possum sIgA. RESULTS: Immunoblotting, using antibodies raised against cloned possum sIgA SC and H-chain, and a synthetic peptide fragment of the H-chain, confirmed the identity of the purified protein. The N-terminal amino acid sequence of purified possum sIgA showed strong homology to reported sequences of H-chain variable regions of marsupial immunoglobulins. CONCLUSIONS: Milk was shown to be a convenient source of mucosal secretion containing sIgA, and a process involving 2 precipitation and 2 chromatography steps produced purified sIgA. This IgA preparation will prove useful for the generation of sIgA-specific immunological reagents for measurement of immune responses in the development of mucosal-based vaccines for biological control of possums. 相似文献
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Fungal endophyte (Acremonium spp.) toxicity affects sheep and cattle grazing a number of forages, including ryegrasses (Lolium spp.) and tall fescue (Festuca nrundinacea). The endophyte in tall fescue is responsible for ill thrift, as indicated by low weight gains or weight loss(1) and decreased reproductive efficiency(2), and is associated with increased body temperatures. Extensive research has been undertaken in the USA to determine ways of reducing the impact of fescue toxicity on the beef industry(3), whilst New Zealand research is directed toward both ryegrass and fescue endophyte toxicity and its impact on sheep(4)(5) and cattle(6) production. Much of this work involves field evaluations of productive performance in animals fed toxic and non-toxic forage, so that it is important to be sure that treatment effects are due to the endophyte. 相似文献
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R.N. Chesterton 《New Zealand veterinary journal》2013,61(4):133-134
Extract Lameness is a significant problem in dairy herds in New Zealand. It affects production and causes cows to lose weight. If antibiotics are used, milk has to be withheld from the vat. Cows may go into extended anoestrus and some which fail to conceive have to be culled. Even in its mildest form lameness is an inconvenience to the normal management of the herd. 相似文献
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AIM: To determine the efficacy of conjunctival vaccination of captive brushtail possums (Trichosurus vulpecula) with bacille Calmette-Guérin (BCG), as measured by immunological responses to vaccination and response to intratracheal challenge with Mycobacterium bovis. METHODS: Nine adult male brushtail possums were vaccinated by the instillation of a suspension of BCG strain Pasteur 1173P2 into the conjunctival sac of each eye. Each drop contained approximately 2.5 × 105 colony forming units (cfu). At 8 weeks post-vaccination (pv) the vaccinated possums and 10 unvaccinated possums were challenged by intratracheal instillation of approximately 100 cfu of M. bovis. Cellular immune responses to bovine purified protein derivative (PPD) antigen were measured using the lymphocyte proliferation assay (LPA). Possums surviving to 50–51 days after challenge were euth anised and subjected to detailed post-mortem examination, including histopathology, to assess protection against tuberculosis. Sections of lung and spleen were cultured for M. bovis. RESULTS: No conjunctival inflammation or other adverse reactions to the administration of the vaccine were evident macroscopically. The vaccinated group showed a systemic cellular immune response to bovine PPD antigen at 4 and 8 weeks pv, and the response at 8 weeks was significantly greater than at 4 weeks (p<0.05). Conjunctival vaccination induced significant levels of protective immunity, measured as less mass of tuberculous lesions in lung (p<0.05) and less dissemination of disease in vaccinated compared with unvaccinated possums (p<0.05). CONCLUSIONS: Conjunctival vaccination with BCG induced a significant level of protective immunity against M. bovis infection in possums. This route of vaccination, together with intranasal aerosol vaccination, could be utilised in the delivery of an aerosolised vaccine using a device that sprays the vaccine suspension into the eyes and nose of possums. 相似文献
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Abstract AIM: To investigate the cause of classical swine fever (CSF) virus-seropositive animals in a nucleus pig-breeding herd in New Zealand, where porcine circovirus-associated disease had been diagnosed. CASE HISTORY AND CLINICAL FINDINGS: An exotic disease investigation was undertaken to exclude CSF and porcine reproductive and respiratory syndrome (PRRS) on a nucleus pig-breeding herd comprising approximately 300 breeding sows, 1,000 weaners, and 650 grower pigs. The herd was experiencing poor reproductive performance in sows, and breeding records showed a declining farrowing rate attributable to a single manager. The growing pigs (10–15 weeks old) were experiencing respiratory disease and wasting, and the mortality rate by pen varied between 9 and 20%. Post-mortem changes in affected grower pigs were consistent with circovirus-associated diseases. DIAGNOSTIC TESTING: Serological screening using an IDEXX-ELISA gave negative results for PRRS virus antibodies, but two grower pigs and one sow tested positive for CSF virus antibodies. These three seropositive animals remained positive to CSF virus, using three commercial ELISA test kits, over 27 weeks. A newly developed virus neutralisation test (VNT), using a New Zealand isolate of border disease (BD) virus, demonstrated that the seropositive pig sera had higher antibody titres to BD virus than to bovine viral diarrhoea (BVD) virus and CSF virus. PCR performed on tonsil, kidney, ileum and spleen gave negative results for CSF virus, and histopathology on lymph nodes, intestine, lung, kidney, liver and brain showed no evidence of the disease. Virus isolation performed on a number of samples was negative. CLINICAL RELEVANCE: The seropositive samples for CSF virus found in this investigation were likely to be a cross reaction to a pestivirus other than CSF virus. The finding of a possible endemic pestivirus capable of being transmitted between sheep and pigs on this farm may explain findings from previous serological survey work in New Zealand, and supports experience elsewhere, where BD virus was found to be the predominant ruminant pestivirus infecting pigs. The results show that pestivirus cross reactivity can result in unexpectedly high titres, and that testing with a full set of (local) pestiviruses is necessary to reach the correct conclusion. The investigation has direct relevance where pig herds with a low seroprevalence are encountered during surveillance for CSF. 相似文献
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为掌握青海省大通种牛场和海晏县牦牛病毒性腹泻/黏膜病、传染性鼻气管炎的感染和流行情况,2010年3月至5月在大通种牛场和海晏地区采集252份牦牛血清样品,应用定量酶联免疫吸附试验（ELISA）对牦牛病毒性腹泻/黏膜病和传染性鼻气管炎的进行了血清抗体检测。结果显示,大通种牛场牦牛群中牛病毒性腹泻/黏膜病阳性率为23.42%,传染性鼻气管炎阳性率为65.45%;海晏县牦牛群中牛病毒性腹泻/黏膜病阳性率为19.86%,传染性鼻气管炎阳性率为4.96%。 相似文献
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A total of 156 chickens in two villages in Malawi were marked and sampled. One hundred and fifteen of these were vaccinated against Newcastle disease immediately after blood sampling, using the V4 heat-resistant strain applied by eye-drop in one village and the inactivated Newcavac vaccine in the other village. A second blood sample was collected 4 weeks after vaccination. The samples were examined using an indirect ELISA test kit. The titre group median ranged from 2 to 3 before vaccination. Both vaccines led to a positive immune response. Newcavac induced higher and more homogeneous titres compared with the V4 vaccine. There was also an increase in the median of the control group where V4 live vaccine had been applied. The differences between the median titres induced by V4, Newcavac and controls were statistically significant. 相似文献
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[目的]为了解凯里市A奶牛场牛呼吸道疫病的流行情况。[方法]本次采用酶联免疫吸附试验（ELISA）对142 份奶牛血清样品进行牛呼吸道合胞体病毒（BRSV）、牛病毒性腹泻（BVDV）、牛传染性鼻气管炎（IBRV）、牛支原体感染抗体检测。[结果]凯里市A奶牛场4 种呼吸道疾病病原普遍存在,BRSV阳性率为41.5%（59/142）;BVDV阳性率为40.1%（57/142）;IBRV阳性率为45.0%（64/142）;支原体阳性率为33.8%（48/142）。犊牛4 种呼吸疾病单一感染率为15.1%~45.5%;BVDV感染最严重,为45.5%;成年牛单一感染率为33.8%~45.1%。此外,奶牛场存在IBRV、BRSV、BVDV、支原体多种病原体混合感染,二重感染率为18.3％~30.2％;BVDV+IBRV感染率最高,为30.2%;三重感染以BVDV+支原体+IBRV感染率最高,为19.7%;四重感染率为9.9%。[结论]凯里市A奶牛场存在4 种疫病,有不同程度的病原体感染,应加强对上述病原体的流行控制,提高奶牛场管理水平,减少奶牛场疫病发生和经济损失。 相似文献
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Dot—ELISA间接法检测鸡新城疫病毒（NDV）的研究 总被引：2，自引：0，他引：2
常规方法分离纯化鸡ＩｇＧ,免疫羊制备羊抗鸡ＩｇＧ二抗,以辣根过氧化物酶（ＨＲＰ）标记制备酶标记物的工作浓度为１：１０００;选用硝酸纤维素（ＮＣ）膜作固相载体,建立检测ＮＤＶ抗原的斑点间接酶联免疫吸附试验诊断方法。检测ＮＤＶ鸡胚毒４０份,阳性检出率１００％;人工感染非免疫鸡的气管组织、肺组织各４７份,检出率为９３．６％;人工感染ＳＰＦ鸡气管组织、肺组织各４０份,检出率１００％。与传染性支气管炎病毒（ＩＢＶ）、减蛋综合症病毒（ＥＤＳＶ）、传染性法氏囊病病毒（ＩＢＤＶ）无交叉反应。试验显示该方法简便、特异、快速、结果直观,便于生产应用 相似文献
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猪瘟和蓝耳病是影响我国养猪业的重大疫病,对其进行定期检测极为重要。为了解规模猪场的猪瘟和蓝耳病的免疫合格情况,2017年4—8月,采用两阶段随机抽样结合便利抽样方法,采集莱州市6个规模猪场的629份血清样品,通过ELISA方法进行猪瘟和蓝耳病免疫抗体水平检测。结果显示:6个猪场的猪瘟和蓝耳病抗体平均阳性率分别为82.19%和92.85%,均高于国家规定的70%的基本要求,但有1家猪场的猪瘟抗体合格率未达到国家规定的最低标准,保育猪群的猪瘟和蓝耳病抗体合格率整体偏低。检测结果表明:莱州市猪场猪瘟和蓝耳病的免疫效果较好,猪群基本能够得到有效保护,但对于抗体合格率偏低的猪场以及保育猪群应注意加强猪瘟和猪蓝耳病的免疫和抗体监测。 相似文献